The ROOT CAUSE Of Allergies, Why They GET WORSE & How To GET RID Of Them | Theresa MacPhail

Dr. Rangan Chatterjee 0:00 30 to 40% of the global population have some form of allergic disease.

Theresa MacPhail 0:07 Yeah, that's correct.

Dr. Rangan Chatterjee 0:08 What's going on?

Theresa MacPhail 0:09 Oh my God, what's going on? Um, so it's 30 to 40% now, but all the experts I spoke to said it's easily gonna be 50% in the next decade, so we're just gonna continue seeing a rise. And partially that's because it tends to track with socioeconomic status. So as countries move into the middle class and upper class, they tend to get more allergic dis- uh, disease. So it really is the richer you get, the more problems you have. So, as some countries are stabilizing, so the United States, the UK, there's constant rates, but in places like India and China, they're just playing catch-up, so their numbers are growing exponentially.

Dr. Rangan Chatterjee 0:52 Yeah. 50% of the-

Theresa MacPhail 0:53 Right

Dr. Rangan Chatterjee 0:53 ... world's population in the next decade are gonna have some form-

Theresa MacPhail 0:57 Yes

Dr. Rangan Chatterjee 0:57 ... allergic pro-

Theresa MacPhail 0:59 To something

Dr. Rangan Chatterjee 1:00 ... problem, right?

Theresa MacPhail 1:01 Right.

Dr. Rangan Chatterjee 1:01 And, and for me, like, when I think about allergies, when I think about this beautiful book that you've written, you've done a really deep dive into the history, what we know, what we don't know, but it strikes me as though the topic of allergies, the rising rates of allergies, really says something quite profound about us as humans, and us as humans and our ability to live in harmony or disharmony-

Theresa MacPhail 1:30 Right

Dr. Rangan Chatterjee 1:30 ... with our environment.

Theresa MacPhail 1:31 Yes, absolutely. I mean, one of the fascinating things is the immune system is so old. So evolutionarily speaking, it's one of the first biological systems to develop. So mast cells, which are one of the main components of the immune system, they're about 500 million years old. So organisms, mammals, developed n- an immune system to cope with their environment. So we've co-evolved with the things in our environment for literally millions of years, and within the past 200 years, we've changed things to the extent that that old system, so the, the system that we have to cope with our environment, hasn't kept up with the changes that we've made to our environment. So I like to say that it's almost as if we're running ni- Windows 95 in a 2023 world where we have to run all of these apps, and there's no possibility for an upgrade, because your immune system, it, it's fairly fast evolutionarily speaking, but it's not as fast as the changes that we're making.

Dr. Rangan Chatterjee 2:44 Yeah. Mast cells being 500 million years old, that is-

Theresa MacPhail 2:50 That's right

Dr. Rangan Chatterjee 2:50 ... that's quite something. I mean, I guess we should explain at this point what a mast cell is.

Theresa MacPhail 2:55 Right. [laughs]

Dr. Rangan Chatterjee 2:55 You've also mentioned the immune system in relation to the topic of allergies.

Dr. Rangan Chatterjee 3:00 So I wonder if we could maybe at this point just go back to basics-

Theresa MacPhail 3:03 Yes

Dr. Rangan Chatterjee 3:04 ... and go, what's the relationship between the immune system and allergies? And then maybe unpick the immune system a little bit and explain innate, adaptive-

Theresa MacPhail 3:13 Right. Yes

Dr. Rangan Chatterjee 3:13 ... what a mast cell is.

Theresa MacPhail 3:14 Yes.

Dr. Rangan Chatterjee 3:15 And, and because I think that'll be really useful right at the top.

Theresa MacPhail 3:17 Yeah. Yeah, absolutely. So there are basically, your immune system is two systems working side by side, and they overlap in their function, but your innate system is older. So that is mast cells and basophils, so white blood cells who are the first line of defense, basically. And like I said, the 500 mils, 500 million years we think for mast cells. So it developed first, and it's called innate because it's online from the time of your birth, and it's basically a system that responds pretty much similarly to everything. So it's there if something is entering us that is harmful or otherwise shouldn't be there, it clicks on and either sends out things like macrophages or something to, like, eat whatever is in us that shouldn't be there, to rip it apart, to get rid of it, to consume it, to, to eject it. And that is always online. The adaptive immune system is newer, so to speak, so it evolved later, and that is the system that remembers things. So that is, it's called adaptive because it adapts to whatever situation that it's dealing with. So those are the antibodies that will remember, say, the SARS coronavirus. So it remembers a part of that, takes a snapshot of it, and then creates cells specifically matched to that thing, and so when they come across it again, they remember it, so to speak, and can put into play a response much more quickly. So the more times that you see something, the more reactive those cells get.

Dr. Rangan Chatterjee 5:05 Yeah. So the innate immune system, or the innate part of the immune system, something we're born with-

Theresa MacPhail 5:12 Right

Dr. Rangan Chatterjee 5:12 ... it's very, very old. It's nonspecific.

Theresa MacPhail 5:16 Right.

Dr. Rangan Chatterjee 5:16 I think that's what we often say when we're talking to patients, is, you know, it, it, yeah, it, it has a few tools.

Theresa MacPhail 5:23 Right.

Dr. Rangan Chatterjee 5:23 It has a few ways of dealing with things, and as you say, it, it, it uses things like macrophages and mast cells, which of course are really important for allergies.

Theresa MacPhail 5:32 Right.

Dr. Rangan Chatterjee 5:33 Uh, I think natural killer cells also are part of the innate immune system.

Theresa MacPhail 5:37 Right.

Dr. Rangan Chatterjee 5:38 And these things, I think people, you know, I think it's useful for people to understand that you're born with it, so I guess as a kid, or as a, I don't know, let's say you're four weeks old and you're exposed to a bug.

Theresa MacPhail 5:50 Right.

Dr. Rangan Chatterjee 5:51 It's likely that your innate immune system is gonna be the one that kicks in.

Theresa MacPhail 5:55 Right.

Dr. Rangan Chatterjee 5:56 Whereas it's this adaptive one is, I guess, what gets tuned up through life as well, through our exposures, doesn't it? And, and in terms of the adaptive immune system and allergies- What's the relationship, because mast cells are behind a lot of the symptoms in allergies-

Theresa MacPhail 6:12 Correct

Dr. Rangan Chatterjee 6:12 ... but that's from your innate immune system.

Theresa MacPhail 6:14 Right.

Dr. Rangan Chatterjee 6:15 Yet often in the book, you're talking about the adaptive immune system in relation to allergies, so can you help tie that together for us?

Theresa MacPhail 6:22 Sure. I mean, I should say that the innate system is good for most things. So the innate system will still kick in in your adulthood when you're exposed to something like a virus. And so the adaptive system kicks in if whatever you've come into contact with has escaped the innate system. So if s- usually, like sitting here right now, our innate systems are just keeping us healthy and, and fine. So it's a, it's a situation where something's been able to evade the innate system, and then the adaptive system kicks in, so to speak. So it's kind of like the, the secondary mechanism that kicks in, and that is the one that is driving some of the allergic reactions via the antibodies. So there are five different antibodies that your body makes, and they all have different jobs, so to speak, and the one that we're most interested in with allergies is called IgE, and that is the one that's behind most allergic reactions, though not all.

Dr. Rangan Chatterjee 7:26 Mm-hmm.

Theresa MacPhail 7:26 It's, it's tricky because there are some, uh, allergies that are not mediated by IgE. So the definition of what an allergy is can get really tricky really fast, especially if you're tying it to that IgE. Like, my father died of a bee sting, but technically speaking, a allergy to bee venom is not IgE mediated. It's the innate system. So those mast cells are firing instead. So it gets really tricky really fast when you dive into it.

Dr. Rangan Chatterjee 7:56 Yeah, that's something you made, I think, really clear towards the start of the book, that a lot of these different esteemed allergy experts have kind of different [laughs] ways of looking at allergies, different definitions.

Theresa MacPhail 8:12 Right.

Dr. Rangan Chatterjee 8:13 And I think that's a theme that, that comes through the book very nicely, is that this is a complex issue. There's no easy fix. There's no easy answer here. There's a, there's a combination of different factors-

Theresa MacPhail 8:25 Right

Dr. Rangan Chatterjee 8:25 ... which I think's, I think's useful to keep in mind because we are living in a culture now where we want quick fixes and quick answers, and what's gonna get rid of my allergies?

Theresa MacPhail 8:35 Right.

Dr. Rangan Chatterjee 8:35 We're definitely gonna get to treatments later on in this conversation, but I think it's really important to understand what these allergies are. Now, we've mentioned how prevalent they are. You know, in the next 10 years, gonna be half, half of us are gonna have some form of allergy, right? Allergies exist on a continuum.

Theresa MacPhail 8:56 Right.

Dr. Rangan Chatterjee 8:56 Right? Some people, it's unpleasant at certain times of year, yet other people, like your father, end up dying from allergies.

Theresa MacPhail 9:08 Right.

Dr. Rangan Chatterjee 9:09 So I wonder if you could, if you, if you're open to it, explain what happened to your dad and also then relate that to this continuum, uh, and maybe to the innate and adaptive system i- i- if you feel it's appropriate.

Theresa MacPhail 9:23 Sure. So I guess what I'll start with is the basic mechanism. So I mentioned these IgE antibodies, and a lot of us have heard the metaphor that our immune cells, our antibodies, or our T cells specifically, are the policemen of the body. So T cells are just a, a class of white blood cells that circulate throughout the body looking for things that shouldn't be there, or suspicious activity, I guess you could say.

Dr. Rangan Chatterjee 9:53 Mm-hmm.

Theresa MacPhail 9:53 And so in that way, they are kind of like policemen patrolling a neighborhood, but what they do is they'll come across something like a virus or an oak pollen, and if they decide it shouldn't be there, what will happen is they'll take a snapshot or almost like a, a protein signature fingerprint of that thing. But then they take it to another class of cells called B cells, another type of white blood cell. You ... I like to think of them as the store managers or the nightclub managers on the street. And so it's basically, you know, "Hey, this, this neighborhood is under threat. Here's a picture of the perp. Please be on the lookout." And then the B cells are producing the antibodies. And so I like to think of IgE as a bouncer, that they're there at the door to these neighborhoods, these different stores, nightclubs, and their job is to decide who gets to come in and who has to stay out.

Dr. Rangan Chatterjee 10:49 Mm-hmm.

Theresa MacPhail 10:50 And but if you think of it this way, every bouncer or every security guard has only one picture, so they're looking for one thing. And so at any entrance, you're going to have maybe, depending on what you've been in contact with, that your body has remembered, that it needs to take care of, you'll have 50, 100 bouncers, and they're all looking for their one thing. But the problem is, like, say the description is, "Oh, this person is 5'7", dark hair, light eyes," a lot of things are gonna look like that, which is why often we'll get cross-reactivities. So you might be allergic to one tree nut, but you're actually going to probably be allergic to more than one because they're all in the same family.

Dr. Rangan Chatterjee 11:35 So it's kind of mistaken identity.

Theresa MacPhail 11:37 Yes. Yeah, and then they turn on the mechanism of let's get this out of here. So it turns into a bit of a rumble, and I guess the nightclub turns into a very unpleasant experience because then they're signaling to other cells, "Hey, we've got a problem."

Dr. Rangan Chatterjee 11:51 Mm.

Theresa MacPhail 11:52 And it starts that system in play, which is driven by histamine. So what happened with my father is partly driven by just his innate, uh, cells. So mast cells are basically the drivers, the conductors, if you will, of this whole orchestra of things that happen, and they emit histamines. It's just a chemical compound that your cells use to signal other cells when they are damaged or-... or stressed. And they are signaling to cells in their neighborhood that there's a potential threat, that something is happening. And so the cells that receive the histamine signal will send out s- histamine as well. So it's a bit like those nuclear reactions, the ping pong. We've all seen the video of someone throwing a ping pong into the mousetrap ping pong room, and before you know it, the whole room is just exploding. That's kind of what histamine does. So the histamine is the ping pong ball, and it just sets off everything around it. And so what histamine ends up doing in the body is it produces all of our symptoms fairly, uh, yeah, most of our symptoms. So histamine will drive your mucus production, which is why we get congested and runny nose and-

Dr. Rangan Chatterjee 13:06 Mm

Theresa MacPhail 13:06 ... eyes. It can swell tissues, so it causes swelling in areas. In my dad's case, he was stung in the neck, so it swelled his neck tissue, which was not great for breathing. But it also, histamine can constrict your muscles around your lungs, which is what happens during an asthma attack.

Dr. Rangan Chatterjee 13:26 Mm.

Theresa MacPhail 13:27 So when the muscles tighten, it gets harder to take a full breath of air. So that's happening. But then histamine is also dilating your blood vessels. And there's a good reason for that, because they m- it makes it more permeable, so all of those first responders of the immune system can get somewhere quickly. But the other effect of that is it crashes your blood pressure. So as your blood vessels dilate, it just makes it harder to get blood to your heart. So it can send people into a cardiac event, which is what happens a lot of the time during anaphylaxis, if you don't stop that histamine reaction.

Dr. Rangan Chatterjee 14:04 Yeah. And your dad, I believe, died within 30 minutes of that sting.

Theresa MacPhail 14:09 That's normal. So if you don't control a severe reaction and you're going into an anaphylactic reaction, you have about 30 minutes before someone dies.

Dr. Rangan Chatterjee 14:19 Okay. Now, let's just pause there, because I want this to be an empowering conversation. I don't want to overly scare people.

Theresa MacPhail 14:27 Right.

Dr. Rangan Chatterjee 14:27 So, um, you know, if we're saying that almost half, half of us are gonna be allergic to something, you have outlined, and thank you for sharing the case of your dad's, a very severe episode of allergy, right? But most people, I think, are not going to experience it to the same level.

Theresa MacPhail 14:50 Correct.

Dr. Rangan Chatterjee 14:51 So, you know, 'cause a lot of people will recognize some of those symptoms.

Theresa MacPhail 14:55 Right.

Dr. Rangan Chatterjee 14:55 Okay? Swelling, itchiness, maybe a bit of tightness. And there's other things with your dad's story that I think are really, really interesting and insightful when we think about the history of allergy and the history of treatment, in that, if I remember rightly from the book, his girlfriend at the time drove him to a pharmacist or a drug store, and an EpiPen was there, I believe, but it wasn't administered. Is that right?

Theresa MacPhail 15:22 They had adrenaline on hand, because of course, you know, they're a pharmacy. But the laws at the time, pharmacists weren't allowed to dole out the medicine on their own. Without a prescription, he couldn't do anything. His hands were tied, so he couldn't give the adrenaline. And that's possibly because, I mean, of course, like, say it looks similar to a heart attack at the end stages when you're going into the cardiac, uh, event. And if you give someone who's having a heart attack adrenaline, [laughs] that's the exact wrong thing to do, and you're gonna make it worse. And so he was just... He thought he knew what was happening. I mean, it was obvious that he had been stung, but just legally, he was afraid to give my dad the treatment. But also at the time, so this was 1996, and it's important to note that date because in the United States, the explosion of food allergies really only started in the 1990s.

Dr. Rangan Chatterjee 16:22 Mm-hmm.

Theresa MacPhail 16:22 So now I think a lot m- more people are prepared, and there have been laws put in place that, uh, people have to have access to adrenaline. So EpiPens are ubiquitous, and so you would be able to find one more quickly. But then there weren't any mandates. So if you were an ambulance company, you didn't necessarily have to have an EpiPen available in your cab.

Dr. Rangan Chatterjee 16:48 But so in 1996, ambulances in America would not necessarily have an EpiPen there.

Theresa MacPhail 16:55 Right. Right.

Dr. Rangan Chatterjee 16:56 I mean, that is... I guess that really speaks to this whole issue, which is how quickly allergies have exploded-

Theresa MacPhail 17:03 Right

Dr. Rangan Chatterjee 17:04 ... and how just, what's that? 30-ish years ago, under 30 years ago? [laughs]

Theresa MacPhail 17:10 Right.

Dr. Rangan Chatterjee 17:10 An ambulance maybe would not carry an EpiPen-

Theresa MacPhail 17:14 Right

Dr. Rangan Chatterjee 17:14 ... or adrenaline.

Theresa MacPhail 17:15 Right. Yeah, it would have... Uh, I mean, perhaps some people were definitely carrying it, so there were people with severe allergies that would have had a prescription for-

Dr. Rangan Chatterjee 17:26 Mm

Theresa MacPhail 17:26 ... something like an EpiPen, but it wouldn't have been to the extent. So prescriptions for EpiPen have just quadrupled, uh, over the span of 30 years. So you're seeing many more people. So I think the last statistic I saw was about five million Americans have a prescription for an EpiPen. It's interesting because that is not who fills them. So about 85% of people who are given a prescription fill it, and some people just never even fill the prescription.

Dr. Rangan Chatterjee 17:56 Yeah. Do you ever reflect and think, had that pharmacist given your dad an EpiPen, what might have happened?

Theresa MacPhail 18:05 It probably would have saved his life. Or if that ambulance company had had the access to the adrenaline, but they didn't, so all they could do was stabilize him. So they were trying to keep his heart stabilized. They were, y- giving him chest compression. Once he started into the cardiac event, they were trying to stabilize his vitals, but it... After that When you've reached that point, it's very hard to stabilize your system, especially outside of the hospital. So the survival rates, if you can get to a hospital within 30 minutes, are quite good.

Dr. Rangan Chatterjee 18:42 Mm-hmm.

Theresa MacPhail 18:42 But it's, it's that key time where you need to halt the, the reaction in time. EpiPens do that wonderfully, which is why we have mandated that they be in schools in the US, so every grade school and middle school and high school has to have a pen on hand. Um, and we have mandated... Although, the United States is interesting. Um, it's state by state, so some states have mandated that all ambulances have to have them, but there are still states where they leave it up to the discretion of who is- ever is running the service.

Dr. Rangan Chatterjee 19:16 Yeah, I mean, there's some wider cultural and ethical issues, I think, around allergies as a whole-

Theresa MacPhail 19:22 Mm-hmm

Dr. Rangan Chatterjee 19:22 ... which you, which you, which you do talk about in the book, and we'll hopefully talk about later on today. But, you know, that's... It's, it's really, really interesting. I mean, how... I know you start the book with that story about your dad.

Theresa MacPhail 19:34 Right.

Dr. Rangan Chatterjee 19:35 It's clearly a big driver for you to go and explore this topic. You seem very calm about it now. Was there frustration and anger for a while that an EpiPen was not given, it was not administered when it was actually there?

Theresa MacPhail 19:52 You know, it's strange because I was so young. I was only 24 at the time, and it was just such a shock that, to be honest, I didn't really think about those things-

Dr. Rangan Chatterjee 20:02 Right

Theresa MacPhail 20:02 ... until later. Until I started researching the book, I never really questioned why there wasn't something on hand. It, it was just such a shocking thing-

Dr. Rangan Chatterjee 20:13 Mm

Theresa MacPhail 20:13 ... to get that phone call that he had passed away. A- an otherwise underly- I mean, he had a few underlying health issues, which is obviously part of this story, so he had a little bit of heart issue anyway. So obviously, if you have underlying issues and then you go into anaphylaxis, it's, it's much harder. I mean, it... So I basically just thought about that, and I, I was terrified of bees [laughs]

Dr. Rangan Chatterjee 20:38 Mm

Theresa MacPhail 20:38 ... for the longest time. Still am not. I mean, I love that they're pollinators, and I, I support bees-

Dr. Rangan Chatterjee 20:45 [laughs]

Theresa MacPhail 20:45 ... but at the same time, I do not like to be in the vicinity of a bee. [laughs]

Dr. Rangan Chatterjee 20:50 Yeah, understandably. So let's just make it super practical then. For someone who's hearing this or watching and thinking, "Okay, well, I've had a bee sting before, and I had a bit of a reaction, but, you know, I was okay," and then they're hearing the story about your father dying within 30 minutes of a bee sting. Have you got anything to say that's gonna help them feel better?

Theresa MacPhail 21:14 [laughs]

Dr. Rangan Chatterjee 21:14 Because what I don't want is people on the back of this to be panicked about everything in life-

Theresa MacPhail 21:20 Right

Dr. Rangan Chatterjee 21:20 ... and go, "Wow, allergies are on the rise. I could die at any moment," right? And so I think we need to be just mindful of that.

Theresa MacPhail 21:27 Yeah.

Dr. Rangan Chatterjee 21:28 Most people are not gonna have that reaction-

Theresa MacPhail 21:30 Correct

Dr. Rangan Chatterjee 21:30 ... to a bee sting, uh, to, to a bee sting.

Theresa MacPhail 21:32 It's so rare. It's so rare. It is .000016 of the population will have that reaction.

Dr. Rangan Chatterjee 21:42 To?

Theresa MacPhail 21:43 To bee venom.

Dr. Rangan Chatterjee 21:43 Okay.

Theresa MacPhail 21:44 Specific. Or wasp venom. So if you're stung by a, a bee or a wasp, your chances of dying are so slim. I think in the last five years it was 60 people total, so...

Dr. Rangan Chatterjee 21:56 Globally or in America?

Theresa MacPhail 21:58 I, I think just in America.

Dr. Rangan Chatterjee 22:00 Yeah.

Theresa MacPhail 22:00 It's a little bit bigger in globally, simply because a lot of people don't have access to things like EpiPens everywhere. Um, they have to be stored at s- at a constant temperature. So, like, in the h- more humid and hot zones, there are a little bit more stings, and so there are a little bit more, um, deadly reactions. But still, on the grand scheme of things, it's nothing compared to something like food allergies, which is a much higher percentage of people are gonna have a potentially serious reaction.

Dr. Rangan Chatterjee 22:32 Yeah. And just to put those statistics in, um, context, I don't have the exact statistics to hand, but I imagine your risk of dying in a car crash is probably much higher.

Theresa MacPhail 22:44 Oh, miles, yeah. Miles higher. [laughs]

Dr. Rangan Chatterjee 22:45 You know, just to, just to really ha- bring some balance to this conversation, um-

Theresa MacPhail 22:51 To be fair, I think your odds of slipping and falling in the bathtub and-

Dr. Rangan Chatterjee 22:55 Are higher

Theresa MacPhail 22:56 ... dying are higher, yes. [laughs]

Dr. Rangan Chatterjee 22:58 Okay, so these are, these are rare things. Obviously, it did happen to your dad.

Theresa MacPhail 23:00 Right.

Dr. Rangan Chatterjee 23:01 Um,

Dr. Rangan Chatterjee 23:03 you mentioned food allergies rapidly increasing in the '90s.

Theresa MacPhail 23:06 Yes.

Dr. Rangan Chatterjee 23:07 And I think food allergies is something that many people are familiar with. I think if you talk to any school caterer these days-

Theresa MacPhail 23:14 Yes

Dr. Rangan Chatterjee 23:14 ... they will tell you, you know, 30, 40 years ago, we might have had one person with an allergy or an intolerance, and maybe at some point we actually talk about the difference between the two.

Theresa MacPhail 23:23 Yes, absolutely.

Dr. Rangan Chatterjee 23:24 But these days it's not uncommon for, uh, school catering companies, school chefs to have to make quite a lot of different meals for the same class.

Theresa MacPhail 23:35 Yes, that's right.

Dr. Rangan Chatterjee 23:36 Now, I know you're a medical anthropologist, so before we get into food allergies, the context here is that there are rapidly increasing rates of allergies, and that can be food allergies, it can be allergies to things that we inhale.

Theresa MacPhail 23:50 Right.

Dr. Rangan Chatterjee 23:51 Um, it can be things on our skin.

Theresa MacPhail 23:54 Correct.

Dr. Rangan Chatterjee 23:54 And of course, those are the three big sources. But what do we know about allergies in indigenous populations? So if we went to a hunter-gatherer tribe, let's say in Tanzania, right, would we find allergies there? Do we find anyone dying from a bee sting, or is there something about the way that they are living which means that's not happening?

Theresa MacPhail 24:17 That's such an interesting question. For the longest time, I think we thought that we wouldn't find as great of a rate of allergy, and that's held true. So if you go somewhere where they're still living ... closer to the land, so they're farming directly, like smaller farm villages or smaller hunter-gatherer tribes, then yeah, you're gonna have a lower level of allergic disease. But interestingly enough, we're finding new data out of places like, a great example is Uganda, where they expected to find lower rates of allergy out in the outside of the city center, so going out into the, the smaller villages. And what they found was that people are developing hay fever and asthma out in the rural regions of countries where we would've traditionally thought that they would've been fine. So something is happening globally, which is really interesting.

Dr. Rangan Chatterjee 25:22 Do we know, and I, I, I know it's probably hard to get this kind of information, that sounds like a modern Ugandan population living out-

Theresa MacPhail 25:31 Right

Dr. Rangan Chatterjee 25:32 ... um, you know, away from cities are now starting to develop allergies. Do we know if that was happening 3, 400 years ago?

Theresa MacPhail 25:41 No. We, I mean, we do know, and the answer is no.

Dr. Rangan Chatterjee 25:44 So traditional hunter-gatherer tribes, traditional indigenous tribes, traditional communities living away from industrialized cities-

Theresa MacPhail 25:51 Right

Dr. Rangan Chatterjee 25:52 ... it looks so they had minimal allergies.

Theresa MacPhail 25:54 Minimal. Always we had the capacity. So if you look back at the history and you look at historical records of, or just the way people were writing, we do know that bee stings w- and wasp stings were always capable of producing what happened to my father. So there's a famous Egyptian king that one of the inscriptions said that he was felled by a wasp.

Dr. Rangan Chatterjee 26:18 Wow.

Theresa MacPhail 26:18 And so we think, well, that sounds like anaphylaxis. So we know that we had that and, and we also know that that evolution there, w- why would we conserve, evolutionarily speaking, DNA that prones us to this kind of response, right? So anaphylaxis means backwards defense. So it's the immune system turning against you, basically.

Dr. Rangan Chatterjee 26:45 Mm-hmm.

Theresa MacPhail 26:45 But accidentally. It's, it's killing you while trying to keep you alive. And so why would we conserve it, that? And they think it is exactly because of things like venomous insects and other venomous snakes, that it might have given us an advantage back then. So the system was in place, but wasn't being triggered by something like bee pollen [laughs] or-

Dr. Rangan Chatterjee 27:10 Yeah

Theresa MacPhail 27:10 ... or not bee pollen, just pollen in general.

Dr. Rangan Chatterjee 27:13 Yeah, there was something I r- I read it in your book about pollen rates are going to, what is it? Is it double by 2040? It was something like that. It was, it was remarkable. It's gon- a- and it's gonna be more potent pollen.

Theresa MacPhail 27:26 Correct. And that's all climate change. I like to say that people who have allergies are the canaries in the coal mine of climate change effects on our biology. So a- I think a lot of us think of climate change as, oh, that's gonna affect us 10, 20, 30 years down the road, and I'm always here to say, no, it's happening right now. It's happening all around you. I, I was checking the pollen counts here, uh, and they're through the roof. They're through the roof everywhere.

Dr. Rangan Chatterjee 27:53 When you say here, you mean since you've been in the UK.

Theresa MacPhail 27:55 Yeah. Yeah. I just for fun, like that's a weird hobby of mine. Wherever I go, I check the pollen count. [laughs]

Dr. Rangan Chatterjee 28:01 Hey, well, you say it's a hobby of yours, but I imagine a sufferer and, you know, I definitely wanna cover the emotional distress that people with allergies often feel. I bet you someone who, who has a severe pollen, uh, allergy is also-

Theresa MacPhail 28:17 Oh, yes

Dr. Rangan Chatterjee 28:17 ... checking them regularly or looking at-

Theresa MacPhail 28:19 Mm-hmm

Dr. Rangan Chatterjee 28:19 ... where they can go on holiday. "Oh, I'm not gonna go there because of the pollen count." So it, it stands to reason that you would do this, but I think that also speaks to what you just said about the Ugandan population. If this is something that's happening to the entirety of our environment-

Theresa MacPhail 28:36 Right

Dr. Rangan Chatterjee 28:36 ... well, of course, no one's gonna be immune.

Theresa MacPhail 28:38 Right.

Dr. Rangan Chatterjee 28:38 Right? Even these communities where we hardly ever saw it, they're not gonna be immune.

Theresa MacPhail 28:43 Right.

Dr. Rangan Chatterjee 28:43 And I, I'm, I'm sort of drawn to this, uh, wonderful quotes [laughs] you put in the book from, is it H.W. Barber and G.H. Oriel, um, published in The Lancet in 1928. "Allergy is beyond question the most important biological and medical problem that exists or ever has existed, for it represents the pathology of the reaction of man and the lower animals to their environment, to the air they breathe, the physical agents such as light, heat, and cold to which they are exposed, the food they eat, and the various parasitic organisms which may invade them." And I love that quote because it, it, it kind of speaks to what you're saying about allergy sufferers being the canary in the coal mine. Something is going on globally, and if you are not a sufferer, you know, great.

Theresa MacPhail 29:36 Right.

Dr. Rangan Chatterjee 29:36 Number one, good for you. [laughs] That's amazing. But you may well go on in and about your life in oblivion.

Theresa MacPhail 29:44 Right.

Dr. Rangan Chatterjee 29:44 You may think, "What is all this allergy stuff that's going on?" You know? And that is, that is very common for people who don't suffer to kind of downplay it. Again, what is it that... You know, we see, we often see this-

Theresa MacPhail 29:54 Mm-hmm

Dr. Rangan Chatterjee 29:54 ... and I say this with, with real sympathy and compassion, but the older generation often will say, "What, what is this?"

Theresa MacPhail 30:00 Yes.

Dr. Rangan Chatterjee 30:01 Right? "When I'm, when we were kids, there were no allergies. Now everyone's allergic to everything."

Theresa MacPhail 30:05 Right.

Dr. Rangan Chatterjee 30:05 But as your book is showing, yeah, you're right. Now, now everyone is allergic to everything. Or, or it's certainly going that way, isn't it?

Theresa MacPhail 30:11 Yeah, and it should concern all of us because it's that delicate balance. So we are part of an ecosystem, and it's easy for us to ignore that, but allergy sufferers can never ignore that because they're in a constant conversation with the world around them. So- I, I have changed my thinking about m- what my body is doing. So right now as we're sitting here discussing things, our bodies are in a conversation with the things around us without our knowledge. So f- you're right, if things are functioning well and you're not getting a negative response, you're oblivious to those conversations. Like, i- think about how many things you came in contact with already today. Like, did you wash your face? Like, did you use a cleanser? Did you shampoo? And you, uh, m- did you use dish soap on your g- glass, like, so you're drinking from that glass. You know, your carpet's emanating particles. Like, it's just, it's constant, and our bodies are constantly having to make decisions about, well, are we gonna tolerate this or not? And in someone who is tolerating it quite well, they can think nothing's happening, but something is happening. And an allergic person is really aware of their surroundings and that conversation to a level that someone without allergies is, is not.

Dr. Rangan Chatterjee 31:41 I remember in my 20s, and again, you know, I was a practicing doctor at the time, so I was, uh, seeing many patients with allergies and, you know, we had a pretty limited armory of treatments to give them. You know, it was pretty frustrating, and I do remember one of my best mates from university at the time, he was an IT professional, and I think he once had to take two weeks off work because of severe hay fever.

Theresa MacPhail 32:08 Right.

Dr. Rangan Chatterjee 32:09 And that was one of the first times, you know, it's interesting, you know, as a doctor you can see it with patients, but when it's, like, one of your best mates who you're like, "Mate, what, you can't go to work for two weeks?" Yeah, he goes, "Mate, I'm floored. I'm exhausted."

Theresa MacPhail 32:24 Right.

Dr. Rangan Chatterjee 32:24 "I can't barely open my eyes. I can't sleep. I'm itchy everywhere." And interesting enough, he's, he's doing very well now, but it can be pretty profound, can't it? It's not just a bit of hay fever. For some people-

Theresa MacPhail 32:37 Right

Dr. Rangan Chatterjee 32:37 ... it's much more than that.

Theresa MacPhail 32:38 Yeah. It's, I think a lot of people think, "Oh, you're just sniffling a little. Like, what's the big deal?" But it is, it does affect your sleep quality. So all of that histamine production, uh, it's, you know, if you're a little bit stuffy, you're not breathing properly, you're tossing and turning all night. If you've got the itch, you, uh, you're just constantly scratching, if you've got ez- eczema. It is really an emotional toll after a while because you're just not feeling your best. So when I first started researching the book, I would wanna talk to regular people that had allergies. And one of the most profound things is that people would say to me, "Why?" [laughs] "You know, you, you wanna sit down and, and have me talk about my hay fever? Like, w- for what reason?" And I said, "Because obviously I wanna hear what it's like to live with that." And once they started, it was almost like being in a confessional booth because we've just become so used to, or it's become so normalized to downplay your own allergies. Like, you don't talk about it. But even if it's causing you to lose sleep or it's affecting your productivity or your focus, like children with allergies do worse in school because they have a harder time focusing because they don't sleep well.

Dr. Rangan Chatterjee 34:01 Yeah.

Theresa MacPhail 34:01 And so that it's just got these knock-on effects. But most of us have been trained like, "Well, don't bring that up. You know, it's not cancer. It's not heart disease."

Dr. Rangan Chatterjee 34:10 Mm-hmm.

Theresa MacPhail 34:10 Like, we could... "Well, it's not diabetes. Like, why are we discussing this?" But once you got someone talking about the effects on their life, it was, it was quite shocking. I mean, they're spending a ton of money on treatments, constant treatments, and trying new things. Um, they're, they're thinking about it, so they're thinking, "Oh, well, I can't go play soccer." Sorry, football. [laughs] "Because it's, the pollen's quite high today, and so I'm gonna avoid that, so I'm not gonna go out with my friends." Like, it's affecting everything in their lives, but they're just so used to internalizing it, and they never quite feel their best.

Dr. Rangan Chatterjee 34:48 Yeah.

Theresa MacPhail 34:49 And I think a lot of us just don't really understand what that's like to your set point if you have respiratory allergies year-round, which a lot of people do, or you had a, uh, you have low-level food allergies and you're constantly anxious about coming into contact with your trigger. It's just emotionally exhausting.

Dr. Rangan Chatterjee 35:07 Yeah. It narrows your experience of life.

Theresa MacPhail 35:11 It does. Yeah.

Dr. Rangan Chatterjee 35:13 Usually.

Theresa MacPhail 35:14 Yeah. I mean, think about your best, most energetic day and how that feels, and then imagine never feeling that way. Like, someone with a constant chronic allergy just kind of feels less good all the time, and they have almost given up hope for feeling the way a non-allergic person feels. So someone with severe eczema, which is one of the worst allergies in my opinion, 'cause it's the hardest to treat, they kind of have just accepted their lot, and they're thinking, "Well, I mean, I'd just like to be normal." Like, that's their goal. It's like they don't even wanna feel superior, like great. They just wanna feel normal. And I think people don't really recognize how that feels for, if you don't have it, it's very hard to imagine-

Dr. Rangan Chatterjee 36:06 Yeah

Theresa MacPhail 36:06 ... so to speak. I almost think, this is gonna sound insane. You know how when you're younger you had, uh, at least in my generation, you had to watch those terrible videos of car crashes so when you were young so that-

Dr. Rangan Chatterjee 36:21 Right

Theresa MacPhail 36:21 ... you would know not to drive drunk or you would know [laughs] not to speed? I almost feel like someone should be shown, like if you really think this isn't a big deal, you should have to watch a video of an anaphylactic response.

Dr. Rangan Chatterjee 36:36 Mm.

Theresa MacPhail 36:36 Because once you've seen it-

Dr. Rangan Chatterjee 36:38 Yeah

Theresa MacPhail 36:38 ... you understand how terrible it is. But if you've never seen it, you think, "Oh, God, this person's ruining my party. What do you mean I can't have peanut butter?"

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Theresa MacPhail 37:19 What do you mean? It, it just, it's, they don't really understand what someone is afraid of or what someone is dealing with.

Dr. Rangan Chatterjee 37:29 Yeah, I guess a lot of the time allergies are invisible, aren't they? I know eczema, I guess, depending on where it is on the body, it may be invisible or visible, but I guess the point I'm, I'm trying to get to is that it's not as obvious as a broken leg.

Theresa MacPhail 37:45 Right.

Dr. Rangan Chatterjee 37:45 Right? So the guy with the broken leg gets sympathy. "Can I help you?" You know, "What can I do to assist here?" You know, "Do you want to sit down?" Whatever it might be. But with the allergies, it's not quite the same. Um, and I, I agree with you. Eczema is, when you've seen patients or you've got it in your family, you, you experience the itching, the discomfort, the inability to sleep, the constant scratching, the bleeding.

Theresa MacPhail 38:12 Mm-hmm.

Dr. Rangan Chatterjee 38:13 And then I'm really struck to what, um ... Is it, who's the, who's the eczema expert in the book you quote quite a lot? Uh-

Theresa MacPhail 38:20 Oh, Dr. Peter Leo.

Dr. Rangan Chatterjee 38:22 Peter Leo.

Theresa MacPhail 38:23 Yeah.

Dr. Rangan Chatterjee 38:23 Yeah. And, you know, in the section on treatments, he says, "The definition of an effective treatment relies almost wholly on the patient's perspective." It's fascinating, isn't it? Because actually, how can we as clinicians determine if that is a successful treatment or not? Basically by what we can see. It's about-

Theresa MacPhail 38:45 Right

Dr. Rangan Chatterjee 38:45 ... how does that patient feel? Has that, you know, maybe you can still see eczema, but if they're not feeling the pain and the discomfort, well, they might regard that as a successful treatment, right?

Theresa MacPhail 38:57 Yeah, exactly. So they're, they might be feeling good enough that they're, they're happy with whatever it is. But it can go the opposite, too. Someone with the clinician's perspective will be like, "Well, your skin is clear," and yet they're still not feeling well. Like, so they're-

Dr. Rangan Chatterjee 39:14 Yeah

Theresa MacPhail 39:14 ... still getting a little bit of itch, or they're still having discomfort. And l- from just a strictly objective perspective, you would say, "Oh, well, it cleared the rash. The itch is lower. So what's this person's problem?" But it really depends on the subjective experience of the person living in that body, and that's a really hard thing. I mean, it's always, as you know, in medicine, it's incredibly difficult to measure things like pain or itch or anything like that because it's, it's fully subjective, and there's not many objective measures to that. So yeah, it can be quite difficult. Like, someone with milder hay fever might not even take an antihistamine 'cause they're just, "Oh, well, this is fine." But someone else might really be struggling with the same symptoms.

Dr. Rangan Chatterjee 40:01 Mm-hmm.

Theresa MacPhail 40:01 And it really depends. But to go back to the sympathy, I mean, I think even other invisible things, so say you've had a heart attack. There's something that there that people can latch onto. Like, it's life-threatening in a way that people understand, and so there's sympathy for that, even if you can't visibly see that someone's had a heart issue.

Dr. Rangan Chatterjee 40:24 Mm.

Theresa MacPhail 40:24 Uh, but there is very little sympathy for someone with allergy because I think there's something about this idea that it's not life-threatening-

Dr. Rangan Chatterjee 40:33 Mm

Theresa MacPhail 40:33 ... that really makes people less likely to be sympathetic.

Dr. Rangan Chatterjee 40:39 Yeah. I think you touched on a really important point, that allergy suffering is not just a mere inconvenience for the party organizer. I think, I think we should talk about these wider cultural issues, actually, because there is a sort of ethical question then, isn't there, as to whose responsibility is it?

Theresa MacPhail 41:05 Right.

Dr. Rangan Chatterjee 41:05 So some people will say, for example, "Why should we have to change what we're serving at this party, or on a plane, let's say-

Theresa MacPhail 41:14 Right

Dr. Rangan Chatterjee 41:15 ... because one person may be suffering?"

Theresa MacPhail 41:18 Yeah.

Dr. Rangan Chatterjee 41:18 Whereas that person may say, "Well, hold on a minute. You know, that could kill me potentially or cause me extreme discomfort." What, what, what, what are these kind of ethical issues do you think we have to navigate as a society?

Theresa MacPhail 41:31 It's really difficult. So I think there was a shift in the last century anyway to thinking about people's medical problems as individual problems. So, you know, it's something with your biology that is dysfunctional, and so therefore it's a you problem. [laughs] And so you take on the onus to, um, fix it. And with allergies, you can't do that because y- the perfect solution to an allergy is to avoid all the triggers, so you don't come into contact with the thing that you're allergic to, but good luck if it's grass. [laughs] What are you gonna do? I mean, that, that pollen is everywhere. Or in the case of food, like yes, it's the individual who's allergic to the nuts, but they can't be in charge of keeping themselves safe. That is a communal problem.

Dr. Rangan Chatterjee 42:29 Mm-hmm.

Theresa MacPhail 42:30 Because they're in the situation of being in the restaurant, say, they can't be fully in charge of keeping themselves safe. They've got to rely and trust that the people that they're interacting with take them seriously and take care in their food preparation. So it is a social problem, and it's not their fault that they have the allergy, it's our fault as a whole society. So we are m- making choices about how we're living in the world that is causing some of us to be more irritated. And so our immune systems aren't coping as well, but we're not causing the environmental problems-

Dr. Rangan Chatterjee 43:17 Yeah

Theresa MacPhail 43:17 ... that led to that individual problem.

Dr. Rangan Chatterjee 43:20 There's something going on that is causing us to be more irritated. That's not just skin irritation and gut irritation, that's, that's just a kind of holistic irritation in relation to our environment. We're, we're not in harmony with our environment anymore, we're being irritated by it, or certainly the interaction of us with the environment is causing irritation. And you could take this beyond allergies, actually. We can say allergies are a societal problem, right? But then let's take something like obesity or type II diabetes. You could argue the same case. You could argue that exposing people to this toxic, um, energy-laden food environment, when we are literally wired to seek out food and seek out calories and store them when it is available, that's our evolutionary hardwiring. Is it an individual's fault-

Theresa MacPhail 44:20 Right

Dr. Rangan Chatterjee 44:20 ... at that point when they're getting obesity or type II diabetes? I mean, we like to say it is, and it's a willpower and, and all this kind of stuff, but the more you really delve into this, and o- of course, we can empower ourselves to make changes, for sure, but we also have to recognize that it's a very problematic [laughs] food environment. And if you took your lean great-great-grandparents-

Theresa MacPhail 44:45 Right

Dr. Rangan Chatterjee 44:45 ... and put them into this environment, you would find a lot of them aren't remaining lean. A lot of them are succumbing, 'cause the environment is driving your behavior.

Theresa MacPhail 44:56 Right.

Dr. Rangan Chatterjee 44:56 So I think there is something, something quite uncomfortable for us all to think about. Because let's get into some of the causes of these allergies, right? Because I think that, that the next part then will become, um, really quite relevant. But I, I would... Well, in fact, before we do that, let's just talk about some of the things you have changed [laughs] -

Theresa MacPhail 45:18 [laughs] Yeah

Dr. Rangan Chatterjee 45:18 ... in the way you're living your life since you wrote this book.

Theresa MacPhail 45:24 I just think about my body in a different way. First of all, I, I understand that my cells are in conversation with all kinds of microbes that, uh, like microbiota that is inside me and on me and in the world. So I have tried to change my habits to kind of support the natural microbiota that's on my skin and in my gut. So I try to eat more fruit and veg. I am terrible, as most of us are. I, I read a statistic the other day that 90% of Americans don't get enough fiber. [laughs] 90%. What? That's most of us. And it's fruit and veg mostly. It's like cruciferous vegetables and, and eating skin on potatoes a- and we just are not doing it enough. So I, I try to make those choices. So I try to eat something green every day, or, and a lot more fruit and whole wheat, and I'm just trying to give my gut microbiome what it needs as well as what I need. So I think about them in that way. Uh, my skin, I think I have really become more aware of what I'm putting on it. So I tend to less is more, so I try to use more simple products with, uh, less ingredients and less often putting things on my skin. I shower every other day to try to give that microbiome a chance to do its thing.

Dr. Rangan Chatterjee 46:58 Mm.

Theresa MacPhail 46:59 I change my sheets less frequently, so every-

Dr. Rangan Chatterjee 47:01 Your bed sheets?

Theresa MacPhail 47:02 Yeah. Every other week.

Dr. Rangan Chatterjee 47:03 Yeah.

Theresa MacPhail 47:03 Because for the same reason. You're, you're tracking in normal bacteria, and you're sleeping in it, and that's kind of normalizing that bacteria on your skin. And of course, you don't want that to get out of control, like you can't go months without changing your sheets. But just giving it a little bit more of a foothold, just trying to think about not just what makes me happy, but what makes the things that make me up happy, because we're not fully human. [laughs] And I'm well aware of that in a way that I think most of us aren't.

Dr. Rangan Chatterjee 47:38 Yeah.

Theresa MacPhail 47:38 I'm, I'm constantly thinking about the organisms on me and in me that are helping me be me.

Dr. Rangan Chatterjee 47:46 Yeah. It, it's truly fascinating. You've spent years delving into the research on allergies, the history, the current treatments, where treatments are going, yet the practical things you've changed are things that we could all possibly start to do.

Theresa MacPhail 48:06 Right.

Dr. Rangan Chatterjee 48:06 You know? Um, we, we didn't really cover ultra-processed foods yet, but we can... I, I think we need to talk about the microbiome and the-

Theresa MacPhail 48:14 Yes

Dr. Rangan Chatterjee 48:14 ... all the various hypotheses that exist as to why allergies are on the rise, because I think that will then inform why you've made these decisions. But a lot of these things that I've become really aware of over the last five, 10 years since I started studying the microbiome-

Theresa MacPhail 48:30 Right

Dr. Rangan Chatterjee 48:30 ... and just realizing You know, everything you put on your skin is getting absorbed, and, you know, you, you, you see this marketing machine. I re- I remember as a kid, right, I remember as a kid, um, teenage boy, you know, Men's Health had just, I think, launched around that time, and you're seeing these male physiques on the cover, and you think, "Wow," you know, "I'm quite skinny. That looks pretty cool." I mean, you start buying it, and you start to read all this stuff about you need to moisturize, you need to exfoliate. You know, when they're trying to get men now into the beauty industry, and I remember maybe when I was 16 or 17, I'd buy this stuff. I'd go into Boots, and I'd buy this stuff, and think, "Yeah, I've gotta do this every day. You've gotta put cream on before you go to bed at night." And about 10 years ago, I thought, "Wait a minute."

Theresa MacPhail 49:18 [laughs]

Dr. Rangan Chatterjee 49:19 "Do I need to do any of this?" I stopped everything. I... Literally everything, and I think I've got pretty good skin.

Theresa MacPhail 49:24 Right.

Dr. Rangan Chatterjee 49:25 And I don't use any products, right? And again, you know, I do pay attention to my lifestyle, what I put in, you know, what I'm being exposed to, for sure, but a lot of the things we consider normal-

Theresa MacPhail 49:39 Right

Dr. Rangan Chatterjee 49:39 ... are just pure marketing. [laughs]

Theresa MacPhail 49:42 I mean, often... So I had more than one allergy expert say to me if he could do an experiment where he forced people to live the way they lived in 1600, minus of course the Plague and TB-

Dr. Rangan Chatterjee 49:58 Mm-hmm

Theresa MacPhail 49:58 ... you know, [laughs] like, not quite taking it that far, but just stripping away all of those modern things that we take for granted, that he would almost guarantee me that the rates of allergy would plummet.

Dr. Rangan Chatterjee 50:13 Mm.

Theresa MacPhail 50:13 That if we simply stopped slathering ourselves in, in things, using harsh detergents to strip our skin, so a lot of the things we use are just, you know, devastating that microbiome, and eating differently, and doing things outdoors more often [laughs]

Dr. Rangan Chatterjee 50:36 Yeah

Theresa MacPhail 50:36 ... not sitting on your dust mite-infested couch watching Netflix-

Dr. Rangan Chatterjee 50:40 Yeah

Theresa MacPhail 50:40 ... for hours at a time, that he- that we just wouldn't have the same problem that we currently have. I mean, most of us don't realize, one of the most shocking things for me was that, you know, the Environmental Protection Agency in the US has 85,000 different chemicals on its Toxic Control Substances Act list. I mean, just think about that, and those are all... I mean, our chemical industry really took off post-World War II, which is, also tracks with the start of the explosion in asthma and hay fever in the US. So there's obviously a connection between all of the stuff we're making and coming into contact with that our bodies have never seen before.

Dr. Rangan Chatterjee 51:25 Yeah.

Theresa MacPhail 51:25 Like, historically speaking, evolutionarily speaking, those 85,000 chemicals, I mean, some of them were natural and existed, but a lot of them are man-made.

Dr. Rangan Chatterjee 51:34 Yeah, and it's hard to avoid this exposure, because I've been reading a study on PubMed recently about commercial dishwasher detergent.

Theresa MacPhail 51:43 Right.

Dr. Rangan Chatterjee 51:44 Right? So that's probably going onto many restaurants and cafes, and actually, the residue that's left, then, on the plates and the cups.

Theresa MacPhail 51:51 Right.

Dr. Rangan Chatterjee 51:51 And then what are you [laughs] kind of-

Theresa MacPhail 51:54 [laughs]

Dr. Rangan Chatterjee 51:54 ... drinking from or eating from, and that can then negatively affect your microbiome. The problem with this whole area, though, is it gets very scary very, very quickly, because it is a barrage of exposure to chemicals, and maybe one or two of these chemicals that are toxic, we could maybe have the resilience to cope with that, but this constant peppering... So my philosophy is very much in my house, where I can control things, I try my best-

Theresa MacPhail 52:26 Right

Dr. Rangan Chatterjee 52:26 ... to limit the exposure. Now, the problem is, when you try and buy these, uh, better quality products that are cleaner and less toxic, they're more expensive.

Theresa MacPhail 52:35 Of course they are.

Dr. Rangan Chatterjee 52:36 Right?

Theresa MacPhail 52:36 Yes.

Dr. Rangan Chatterjee 52:36 So then you've got this whole cost issue, and we've not even started on air pollution yet, and people in lower socioeconomic classes living near more air pollution, near roads, their rates of asthma and allergy are higher than others. You've covered all of this in your book. So it is a societal issue, isn't it?

Theresa MacPhail 52:54 Yeah.

Dr. Rangan Chatterjee 52:54 It really is.

Theresa MacPhail 52:55 I mean, it really is. We can't... Because we're born into the world that we're born into. I mean, it, there's systems already at play, and so yeah, if you're happening to be born next to a bus depot, you don't really have a choice about the exposures you're getting.

Dr. Rangan Chatterjee 53:11 Well, what about, as you've outlined in your book, if you're born by cesarean versus vaginal delivery?

Theresa MacPhail 53:18 Right.

Dr. Rangan Chatterjee 53:18 Again, you don't make that choice.

Theresa MacPhail 53:20 Right.

Dr. Rangan Chatterjee 53:20 And of course, there are some very, very good reasons-

Theresa MacPhail 53:23 Yes

Dr. Rangan Chatterjee 53:23 ... to have a cesarean section.

Theresa MacPhail 53:24 Yes.

Dr. Rangan Chatterjee 53:24 I completely get that.

Theresa MacPhail 53:26 Yeah.

Dr. Rangan Chatterjee 53:26 But there is a consequence.

Theresa MacPhail 53:28 There is, because, uh, what they've found, what researchers have found is there... So our immune systems need to get trained, in essence, so that adapted immune system that we were talking about, those cells need to be trained to recognize what's acceptable and what they can tolerate and what they can't, and that starts at birth. So when you travel through the vaginal canal, you're picking up your mother's natural... Like, our genital tract has its own microbiome.

Dr. Rangan Chatterjee 53:57 Mm.

Theresa MacPhail 53:57 So they're getting exposed-

Dr. Rangan Chatterjee 53:59 Yeah

Theresa MacPhail 53:59 ... to that as they're passing through the vaginal canal. If you're being delivered via C-section, you don't get that exposure to those bacteria, and it turns out that the order of bacteria that you are exposed to, so first you get the vaginal canal, then you get bacteria in mother's milk, so when you're breastfeeding, you get different things, and you're also getting, interestingly enough, milk, uh, m- breast milk has components that also feed bacteria. So you're getting seeded with bacteria, but then you're getting a source of food for not just the baby, but for the bacteria that you've been seeded with, and it turns out that that order is necessary for a healthy gut microbiome.

Dr. Rangan Chatterjee 54:46 And then why would it not be necessary, right? If we think about this-

Theresa MacPhail 54:49 [laughs]

Dr. Rangan Chatterjee 54:49 ... on an evolutionary level-

Theresa MacPhail 54:50 Yes

Dr. Rangan Chatterjee 54:52 Tens of thousands, hundreds of thousands of years, there is a way in which we come out into the world

Theresa MacPhail 54:58 Right

Dr. Rangan Chatterjee 54:58 Uh, and I think I read in your book that it starts off lactobacillus is what gets seeded initially, I think. I, I, I can't remember if that's exactly correct, and then it changes when, what's coming through the breast milk. Now, always mindful of parental guilt when-

Theresa MacPhail 55:13 Right

Dr. Rangan Chatterjee 55:13 ... I'm having these, um, conversations, because clearly if that is your child and they've got allergies now, you can hear this and start to beat yourself up.

Theresa MacPhail 55:24 Of course.

Dr. Rangan Chatterjee 55:25 Right, so there's, we, we definitely don't want that.

Theresa MacPhail 55:27 Right.

Dr. Rangan Chatterjee 55:28 Um, in fact, what would you say to that?

Theresa MacPhail 55:31 I would say that you didn't cause your child's allergies. I, I mean, it's so complex, as we'll get into. I mean, that's just one part of the story.

Dr. Rangan Chatterjee 55:39 Mm-hmm.

Theresa MacPhail 55:40 So sure, uh, they didn't get the same microbiome start- starter pack, [laughs] if you will, that other children get, but that's, that's perfectly fine for a lot of children.

Dr. Rangan Chatterjee 55:52 Exactly.

Theresa MacPhail 55:52 Like, they're not going to get allergies. So it is such a combination of factors that it's almost a waste of time to try to figure out why your child has allergies. That's what I would tell people. Because they do become archeologists of their own lives.

Dr. Rangan Chatterjee 56:10 Mm-hmm.

Theresa MacPhail 56:10 Like, y- when someone has a child that develops a moderate to severe allergy, they spend a lot of time going, "What did I do? What did I do?" Nothing. Nothing to cause this anyway. I mean, it's just such a complex series of events that led to your child developing allergy, and we really don't even understand why certain cells make the decision to react poorly.

Dr. Rangan Chatterjee 56:35 Yeah. That's something that comes, comes through very clearly in your book, is that we've got a lot of theories, there's a lot of science supporting certain theories-

Theresa MacPhail 56:43 Right

Dr. Rangan Chatterjee 56:43 ... but no particular theory in isolation explains everything.

Theresa MacPhail 56:47 There's no smoking gun

Dr. Rangan Chatterjee 56:48 It's multi- it's multifactorial. I, the way I look at it is as, you know, that if the immune system is a sort of, um, I don't know, permeable barrier, I guess, then we've just overwhelmed it with a-

Theresa MacPhail 57:02 Yeah

Dr. Rangan Chatterjee 57:02 ... with a whole variety of different ways. Yes, one could be over-medicalizing some births. One could be the overuse of antibiotics.

Theresa MacPhail 57:11 Right.

Dr. Rangan Chatterjee 57:11 One could be the cleaning products that are used everywhere. In every cafe you go, and there's, they're just spraying this stuff on every table before you come, so you can actually breathe it in as you're going, you know? And actually w- w- [laughs] when you learn what that is doing to our microbiome, you're like, "What? Do- there's- there must be another way." But that particular cafe, and this is the whole individual versus societal conflict that I think there is, that individual cafe just wants a clean, non-greasy table for its customers. The quickest way to do that is to get a toxic spray, spray it there, and you, all the stuff that was spilled beforehand, all the grease on the, the last client's plate, that goes. So you've got a nice, clean table for your new client, okay? You keep it moving, you keep taking your money in.

Theresa MacPhail 58:00 Right.

Dr. Rangan Chatterjee 58:00 I get it.

Theresa MacPhail 58:01 [laughs]

Dr. Rangan Chatterjee 58:01 I'm not having a go at anyone, right? That's, that's clearly what's gonna happen. But if we expand that out over every cafe and every restaurant, and then you think, what is in those sprays? What are we ex- being exposed to? What are we picking up on our hands, the hands are then going into our mouth? If you are susceptible, and of course some of us, you know, as evidenced by the fact that maybe 60 to 70% currently of the world's population do not have-

Theresa MacPhail 58:27 Right

Dr. Rangan Chatterjee 58:27 ... allergies, right?

Theresa MacPhail 58:28 Correct.

Dr. Rangan Chatterjee 58:29 So that means that some of us, for whatever reason, [laughs] have the ability to not react as of-

Theresa MacPhail 58:35 We're coping

Dr. Rangan Chatterjee 58:36 ... yet anyway.

Theresa MacPhail 58:37 I f- yeah, exactly. We're coping better.

Dr. Rangan Chatterjee 58:39 Yeah.

Theresa MacPhail 58:39 So the people that don't have an allergy are just coping with that situation. But they're still in that situation, and I would say there's a tipping point. So what an allergic reaction really is, is so your individual T cells, like say they... So theoretically speaking, if you're a scientist and, and, or a scientifically minded person, you've got a perfect control experience. So you've got the genetics are the same. You've got the environment's the same, and you've got the exposures are the same. All our cells in our body are, should be exactly the same, which means we should be able to predict how they react. So for someone allergic to peanuts, when those cells come into contact with the peanut, all things being considered, you would think two T cells meet this protein in the bloodstream and, and will make exactly the same decision, and they don't. So one will see that protein and go, "That's fine. Tolerate. Move along." And one will s- come across the exact same protein and say, "Nope, I've gotta deal with you. This is terrible," and turn on the reaction. What an allergy is is just the tipping point of more of their cells making that decision that it's not okay to stay than not. So in a person reacting to pollen, some of their cells aren't reacting, and vice versa. So in a non-allergic person, some of your cells are still-

Dr. Rangan Chatterjee 1:00:07 Mm

Theresa MacPhail 1:00:07 ... saying, "This isn't okay," but it's a fraction of the cells, so you're not experiencing the symptom.

Dr. Rangan Chatterjee 1:00:14 Yeah. That's, that reminds me of a conversation I had about cancer, and how we all as adults have cancer cells within us.

Theresa MacPhail 1:00:25 Right.

Dr. Rangan Chatterjee 1:00:26 But, you know, the immune system's on top of it, and, you know, the balance is, is, is such that we don't have the diagnosis of cancer. It's when the balance starts to change. And it's maybe not quite the same thing, but it, it's quite a similar, I think, theme there, that things are going on in the body always, and just because we're not getting symptoms doesn't mean [laughs] there's no problem.

Theresa MacPhail 1:00:51 Right. In fact, there's an interesting overlap there. So people that have allergies tend to have lower rates of certain types of cancer, specifically certain forms of skin cancer and some gliomas. And one of the theories, we don't know why, I mean, it's c- could just be correlation and not causation, but one of the theories is perhaps someone who's allergic h- actually has a really strong immune system. I think there's this idea that people w- with allergies are weak or somehow maladaptive.

Dr. Rangan Chatterjee 1:01:23 Mm-hmm.

Theresa MacPhail 1:01:23 And actually, they have incredibly strong immune systems that are just responding to the wrong-

Dr. Rangan Chatterjee 1:01:29 Mm-hmm

Theresa MacPhail 1:01:29 ... stimulus. And so their bodies might be able to spot cancerous cells more quickly and more aggressively because they're already primed to respond, if that makes sense.

Dr. Rangan Chatterjee 1:01:43 Yeah. That's really interesting, isn't it? Allergy sufferers may have lower rates of certain cancers. And, and it makes me think, I mean, we're gonna talk now about the gut microbiome. I really wanna get your perspective on that in relation to allergies, and you, you, you, you referenced a lot of, uh, Dr. Catherine Nagler in the book-

Theresa MacPhail 1:02:02 Yes

Dr. Rangan Chatterjee 1:02:02 ... around this.

Theresa MacPhail 1:02:03 Yeah.

Dr. Rangan Chatterjee 1:02:05 But this idea that the gut microbiome is really important, and regular listeners to my show will be aware of the microbiome. We've covered it many times on the show in, specifically in relation to what foods and, and what lifestyle changes can help support a stronger and more resilient microbiome. But when I think of allergies and I think about this is a, a, an immune system that, I don't know if misfiring is the right word, is something's just out of balance with the immune system, I'm also drawn to autoimmune disease-

Theresa MacPhail 1:02:42 Right

Dr. Rangan Chatterjee 1:02:42 ... where in autoimmune disease, the immune system is reacting against itself-

Theresa MacPhail 1:02:51 Correct

Dr. Rangan Chatterjee 1:02:51 ... or the body's own cells. An analogy, the immune system is reacting to the outside world. And then I've read so many interesting studies on, I think it's in Indian villages, where, uh, people who have the presence of certain parasites, like Blastocystis hominis, have got lower rates of autoimmune disease.

Theresa MacPhail 1:03:14 Right.

Dr. Rangan Chatterjee 1:03:15 So as I've been reading your book over the last few days, I've really been thinking about this potential conundrum whereby is the cost of having a, in inverted commas, clean world where we don't get infections as much, is the cost of that an increase in allergies and an increase in autoimmune disease? Whereas in certain cultures where they have, uh, regular parasitic infections, and maybe they're getting symptoms of that, there, there does appear to be evidence suggesting that they have certainly lower rates of autoimmunity. I, I can't say I'm aware of the research for lower rates of allergies, but I suspect it may well be. So is it that we need almost that low-grade infection in our gut to tune up our microbiome and our immune system, which then is protective? Do you know what I mean? I've, I, I really think about this, so is it even possible?

Theresa MacPhail 1:04:17 Yeah. I, I mean, w- we're not... I wanna be really careful here because I'm, I'm sure you're aware that there's an underground movement where people are ingesting, they're, they're trading and ingesting, uh, worms, intestinal worms, to try to self-treat things like eczema, but s- often they cause themselves trouble. [laughs] So they'll ingest pinworms to try to tamp down the immune system, and it does seem to work some of the time. So one of the theories is that, so our immune system was built for a different world. So we were coming into contact with a lot more venomous things. We had a lot more parasites. And so th- the allergic part of the, so the different pathways that the immune system can take, that the allergic-

Dr. Rangan Chatterjee 1:05:08 Mm-hmm

Theresa MacPhail 1:05:08 ... part and the autoimmune part is basically was built for those things, so that it would protect you. And in fact, they've done studies in mice where if you knock out those IgE antibodies that I was talking about, and then you give the mice, uh, do- doses of a snake venom that was commonly found in Israel, that it, those mice die at a much higher rate. So their anaphylaxis just, you know, they go straight into toxicity and, and expire. But if they have the IgE, it actually does have a mildly protective effect, so they survive more often. So there's obviously something about this system that was built to protect us against certain things that just... I mean, I don't know about you, but I haven't been s- bitten by an asp any time recently. [laughs]

Dr. Rangan Chatterjee 1:06:06 Yeah.

Theresa MacPhail 1:06:06 I'm not regularly getting snake bites. And so the the- one of the theories is that that part of our immune system is rather like a bored toddler. So I don't know. I mean, I know you have children, so if you, if you leave them with nothing to do, they'll find something to do.

Dr. Rangan Chatterjee 1:06:22 Yeah.

Theresa MacPhail 1:06:22 And so [laughs] and it's not necessarily what you want them to be doing. And that, so that, those components of our immune system is like that. They're there, they're ready to work, but they're not being given the things-

Dr. Rangan Chatterjee 1:06:36 Yeah

Theresa MacPhail 1:06:36 ... that they normally would've been given, and so they're kind of looking about for things to do.

Dr. Rangan Chatterjee 1:06:42 Yeah. It's like the subtitle of your book, How Our Immune System Reacts to a Changing World. You know, that's kind of it in a nutshell, isn't it?

Theresa MacPhail 1:06:52 Yeah.

Dr. Rangan Chatterjee 1:06:53 In the book, you outline, you go through the, the sort of various theories of it that have come over time as to why we are so allergic.

Theresa MacPhail 1:07:01 Yeah.

Dr. Rangan Chatterjee 1:07:01 You mentioned the hygiene hypothesis, the barrier regulation hypothesis, and I think you've coined something called the we are doing it to ourselves hypothesis.

Theresa MacPhail 1:07:11 [laughs]

Dr. Rangan Chatterjee 1:07:12 So, which I really like. I think that could catch on. Um-

Dr. Rangan Chatterjee 1:07:16 Perhaps you could sort of walk us through some of these theories and what do we know-

Theresa MacPhail 1:07:21 Right

Dr. Rangan Chatterjee 1:07:21 ... as of 2023?

Theresa MacPhail 1:07:23 I'll start with the hygiene hypothesis, 'cause you- if anyone has heard anything, it's probably this one, that we're too clean. So the original theory was based on research, a meta study, so a researcher's looking at all the various studies looking at specifically asthma and respiratory allergy rates in, I think, Britain. And what he discovered was that younger children, so if you were in a multi-, um, sibling household and you had elder siblings, you seemed to be protected from allergic disease. So the oldest one might have allergies, but the youngest had much lower risk of developing allergic disease. And so this researcher posited that why would that be, and he thought, "Well, kids are germy. Like, you know, they go off to school, they bring things back, you're constantly getting sick. So that what will happen is that the younger children will get exposed to all of those things at a young age, and then somehow that was having a protective effect."

Dr. Rangan Chatterjee 1:08:24 Mm.

Theresa MacPhail 1:08:25 So that got turned into this idea that was supported by a couple of studies that were done in Germany and, um, Switzerland, that, uh, suggested that living closer to microbes, specifically those in barns, so it's called the farmhouse effect, and it's related to the hygiene effect. And basically, what they found is if you lived in a farming community, and as a child you were being carried in and out of a barn with ducks and cows and pigs and what have you, and the key thing was the livestock. They don't know why, but if the farm had livestock and the child was brought into the barn on a regular basis before the age of three, the rates of allergic disease were incredibly low-

Dr. Rangan Chatterjee 1:09:14 Right

Theresa MacPhail 1:09:14 ... when those children got older. And they really don't know what's so magical about farm dust. [laughs] Uh, they don't know, maybe it was the animal dander mixed with bacteria-

Dr. Rangan Chatterjee 1:09:25 Yeah

Theresa MacPhail 1:09:26 ... mixed with allergens. So you know, of course you have hay, and so you would have natural allergens also in that barn. And so they think maybe there's something about that mixture, that f- farm dust from a farm that has livestock was pr- protective. And so that lent itself to the hygiene hypothesis. But we now know, like, if you look at farming communities now, they have the exact same rates of disease, and we kind of have discredited that as the smoking gun. So it can't just be that we're too clean. And the other evidence is that we got clean a lot sooner than we got allergies. So if you think about the history of hygiene and all the sanitation efforts, we started to clean up our act, so to speak, a lot quicker than we got the bump of allergic disease, which really started blossoming after World War II.

Dr. Rangan Chatterjee 1:10:23 But could that also be, if we think about the innate and the adaptive system and how the adaptive system takes a bit more time, it's... And, you know, if we get time today, I wanna talk about how repeated exposures-

Theresa MacPhail 1:10:36 Right

Dr. Rangan Chatterjee 1:10:37 ... can often get worse. Or you have this scenario now where, uh, if that's a friend's friend yesterday when they knew I was speaking to, she said, "Hey, listen, can you ask Theresa about my, I think it's my mom, who never has had hay fever before, but after she cut the grass a few weeks ago, felt really bad. And when she stopped..." Like, so this, uh, this idea that, um, repeated exposure can start to... You know, people can suddenly get symptoms in their 60s when they've-

Theresa MacPhail 1:11:06 Right

Dr. Rangan Chatterjee 1:11:06 ... never had an allergy before, which I think is pretty common now, that people are getting it later on in life. So-

Theresa MacPhail 1:11:11 Yeah

Dr. Rangan Chatterjee 1:11:11 ... I wonder, 'cause, 'cause we know that, you know, that research has shown that kids who grew up in these farms had a lower rate. It doesn't mean you're never gonna get it. Doesn't-

Theresa MacPhail 1:11:21 Right

Dr. Rangan Chatterjee 1:11:21 ... but just a lower rate. So as you say, it's maybe not the smoking gun, but it could be part of the story, right?

Theresa MacPhail 1:11:29 Right. And the reason we think that is this dovetails into the microbiome or the barrier hypothesis nicely. So we've updated the hygiene hypothesis to something we call the old friends theory, which is that, sure, obviously, it's great that we don't have TB anymore, or, like, cholera is not a serious problem for a lot of us. But that there's really good f- bacteria that are helpful to us and bad bacteria, like cholera, that we obviously don't want, but the problem is, is that antibiotics, uh, sanitizers, they don't discriminate, so they're indiscriminately killing everything, and that they're killing our friends. And so if you look at the gut microbiome, so Kathy Nagler at the University of Chicago has looked at babies who have allergic disease, and when you look at the genetic makeup of their guts, they're strikingly different from babies that do not have allergic disease.

Dr. Rangan Chatterjee 1:12:32 Mm.

Theresa MacPhail 1:12:32 So there's a different composition of the types and numbers of bacteria in those guts. And so her hypothesis is that the gut microbiome has a key role in regulating the immune system, so that our immune system trains itself partially on the trillions of-

Dr. Rangan Chatterjee 1:12:54 Mm

Theresa MacPhail 1:12:54 ... m- organisms inside of us. And if those get off balance or if there are types that perh- perhaps weren't there in the past or, and they're absent some types that we would have evolutionarily, um, co-evolved with, that those changes are causing our immune system to have a tougher time regulating and a tougher time, um, training In-

Dr. Rangan Chatterjee 1:13:23 Yeah

Theresa MacPhail 1:13:23 ... in the early years, so from age zero to three, is when your immune system really changes a lot.

Dr. Rangan Chatterjee 1:13:31 Yeah. It reminds me of, I don't know w- if the book came out 10 years ago now, Missing Microbes by, I think it's Martin Blaser, from recollection, where he put forward the idea that, you know, him and many others, I think, put forward this idea that is the fact that our microbiomes are so deplete relative to what they were before-

Theresa MacPhail 1:13:55 Right

Dr. Rangan Chatterjee 1:13:55 ... or what they are in some hunter-gatherer tribes even to this day.

Theresa MacPhail 1:13:58 Yeah.

Dr. Rangan Chatterjee 1:13:58 The fact that we maybe have lost up to 50% of our diversity, some studies are showing, I think some maybe even more than that, is that these missing microbes that is ultimately underpinning our dramatically increasing rates of autoimmune disease, allergy, other chronic diseases. And it's, it's really interesting, and I guess that fits with this old friends hypothesis. And you mention, um, Katherine Neagler in the book quite a lot about food allergies, but you also mention, uh, when, when it comes to microbiomes, I think it's, you know, you mentioned the vaginal microbiome, but there's microbiomes everywhere.

Theresa MacPhail 1:14:32 Right.

Dr. Rangan Chatterjee 1:14:33 There's a microbiome on your skin, and you quoted a study I think where they put a strip, an adhesive strip, on someone's... They had a control group. I mean, do you know, maybe you could... Said the study, it was really interesting.

Theresa MacPhail 1:14:46 Yeah, it was actually mice. So what she did was she, uh, she stripped the microbiome using adhesive tape of mice, and then, uh, applied an allergen.

Dr. Rangan Chatterjee 1:14:58 Yeah.

Theresa MacPhail 1:14:58 And what she found is if you strip that microbiota, then the mice had a much... I mean, basically, the skin becomes leaky or more porous. The allergen gets into the skin and into the bloodstream immunologically intact, which means that it's not being broken down. So usually when things come into us, it's through our digestive tract, and we break things down.

Dr. Rangan Chatterjee 1:15:26 Mm.

Theresa MacPhail 1:15:26 And then, of course, they're absorbed into the bloodstream, but not in their intact form, and it's really when our bodies get it intact that it goes, "Hey, wait."

Dr. Rangan Chatterjee 1:15:37 "What is this?" [laughs]

Theresa MacPhail 1:15:38 "What is this?" And so one of the theories, especially about food allergy, is that, and of course eczema, is that when you strip that microbiome f- or change it on the skin, that you are priming your immune system to be like, "Hey, what, what's going on?" Like, "This shouldn't be here." Like, things are getting in in forms that they wouldn't normally get in. So it's possible, they think, that, say you make a peanut butter sandwich, and then you pick up your baby, and you have traces of peanut on your hands, and if your baby is unfortunately, you know, carrying a genetic predisposition and has, uh, more porous skin, that that peanut butter is seeping in, and then they, when they eat peanut butter, their bodies will have been pre-sensitized via the skin.

Dr. Rangan Chatterjee 1:16:29 Mm-hmm.

Theresa MacPhail 1:16:29 So it's not even their... It wouldn't be their first time coming across peanut is not via the normal route. It's through the skin.

Dr. Rangan Chatterjee 1:16:38 Yeah.

Dr. Rangan Chatterjee 1:16:42 You mentioned the early years and those first three years of life, and how the exposures a child has at that point, a baby has at that point, an infant, toddler, right, are really crucial at determining what's the signature of that microbiome going to be. And we know [laughs] don't we, that actually what happens then can hugely influence what happens later on in life. Now, again, I don't want anyone to feel guilty-

Theresa MacPhail 1:17:16 Right

Dr. Rangan Chatterjee 1:17:16 ... about that, right?

Theresa MacPhail 1:17:17 [laughs]

Dr. Rangan Chatterjee 1:17:17 Please, a- as I say it, I can just, I can just hear and feel the parental guilt. Uh, and just to be clear, right, if I knew everything I knew now when my kids were born, I would do some things very, very differently, for sure, right? I think, I'd like to think I've done a lot right, but, you know, we're all doing the best that we can.

Theresa MacPhail 1:17:36 Right.

Dr. Rangan Chatterjee 1:17:36 I wanna make that super, super clear at the top here. But the fact that those early years are important, I think there's, there's a really, there's a really important wider point here, I think. We're learning that... I spoke to Dr. Gabor Maté a few weeks ago-

Theresa MacPhail 1:17:51 Right

Dr. Rangan Chatterjee 1:17:51 ... um, o- on the show, for the fourth time, actually, and again, Gabor was talking about the early years, how we're parented, how we form attachments, are really important for the state of our nervous system and our risk of all kinds of problems later on in life, right? So from a mental health perspective, early year attachments are important. From an allergy perspective, right, and risk of autoimmune disease in the future, the inputs that go into a child and a baby from food and what's on their skin is also very, very important.

Theresa MacPhail 1:18:30 Yes.

Dr. Rangan Chatterjee 1:18:31 And then you've gotta ask the question, as societies, what are we doing to support those critical early years? Because if all healthcare systems are struggling, if allergy rates are going up, yet we can say we don't know everything yet, but we do know that the early years are important, surely it makes sense [laughs] to go, as societies, how can we support parents, communities, families in those early years? But it's... And you come from a country where, I would say, certainly from the UK, now I'm not saying we're perfect at all, especially when it comes to if you compare us to, let's say, certain Scandinavian countries.

Theresa MacPhail 1:19:08 Right.

Dr. Rangan Chatterjee 1:19:08 But, you know, in the US, uh, you know, maternity leave and... I- it's, it's crazy.

Theresa MacPhail 1:19:14 Yeah.

Dr. Rangan Chatterjee 1:19:15 You know, or I would... Uh, it certainly, it definitely feeds a capitalist system.

Theresa MacPhail 1:19:19 Yeah. [laughs]

Dr. Rangan Chatterjee 1:19:19 It serves that very, very well-

Theresa MacPhail 1:19:21 Yeah

Dr. Rangan Chatterjee 1:19:21 ... but does it serve the health of the children, and therefore- Healthcare systems, no

Theresa MacPhail 1:19:27 No, not at all. And you can see this play out in socioeconomic groups, and of course, in the US, that tracks often with racial groups. So you will find higher rates of asthma in underserved communities, higher rates of, uh, food allergy, except that it's not as diagnosed, and there are various reasons for that. But, uh, you know, they're growing up, to go back to the air pollution, uh, connection, you know, like, that's something you can't control. So they've shown that, you know, if... So they did this research at Cincinnati Children's Hospital, where they took children that were born, just random as- assigning groups where you were either really close to a roadway, where you had a lot of diesel engines and trucks going by, or you lived further away. And what they found was that the closer you are to exhaust, the higher your chances of developing asthma. And with, if the child moved, if it was after the first three years of life, that risk te- continued. So it's obviously in the early years that are critical, and it matters where someone lives, and the air that they are breathing, and the food quality that they are having. So like, you know, in the US, we do have food stamps or, you know, af- assistant programs. But they're patchy, and it's hard to get approved in some states. And so what's the quality of the food that the parents are giving these young children? And again, it's not their fault.

Dr. Rangan Chatterjee 1:21:06 Yeah, it's not the kid's fault. It's not the family's fault.

Theresa MacPhail 1:21:09 Right.

Dr. Rangan Chatterjee 1:21:09 And then there's also researches there that you share that if up to the age of three, if you grow up with a pet-

Theresa MacPhail 1:21:16 Right

Dr. Rangan Chatterjee 1:21:16 ... like a dog, you also have lower rates-

Theresa MacPhail 1:21:19 Yeah

Dr. Rangan Chatterjee 1:21:20 ... of allergy.

Theresa MacPhail 1:21:21 And they think that's, again, bacteria. So the dog is out in the world, snuffling around [laughs]

Dr. Rangan Chatterjee 1:21:27 Yeah

Theresa MacPhail 1:21:27 ... and then coming in and licking your kid's cheek. [laughs] And that that low-level, uh, bacterial introduction is actually somehow protective again.

Dr. Rangan Chatterjee 1:21:36 But again, it's, it's this whole wider point where we have been trained to go, "All bugs are bad."

Theresa MacPhail 1:21:41 Right.

Dr. Rangan Chatterjee 1:21:42 "We need to kill bugs." And listen, of course, antibiotics have been-

Theresa MacPhail 1:21:45 Yes

Dr. Rangan Chatterjee 1:21:46 ... lifesaving, right?

Theresa MacPhail 1:21:47 Yeah.

Dr. Rangan Chatterjee 1:21:47 I, I completely get that.

Theresa MacPhail 1:21:49 [laughs]

Dr. Rangan Chatterjee 1:21:50 But like with most things in life, there's upsides and there's downsides, and there has been a huge downside not only with antibiotics for the over-prescription of antibiotics in humans, but also all the antibiotics being used-

Theresa MacPhail 1:22:04 I know

Dr. Rangan Chatterjee 1:22:04 ... in cattle. I mean, how does that play in here?

Theresa MacPhail 1:22:06 It, it plays in a great deal. I mean, uh, you know, most of the researchers I spoke to just lament that because it is killing off commensal bacteria that drive our immune systems. So you're... And they have found that, unfortunately, again, like I don't want... I also am worried about people feeling guilty, but if children have a lot of antibiotics prior to the age of two, so say you, you had four bad ear infections, so you got four massive doses of antibiotics when you were younger, it does lead to a higher instance of allergic disease when they're older. And the theory is that it is dramatically changing the microbiome because of, again, a, an antibiotic is, uh, like a sledgehammer. It's just knocking out every bacteria. It's not distinguishing.

Dr. Rangan Chatterjee 1:22:56 Yeah, and we, and we know from the research that some microbiomes bounce back quickly.

Theresa MacPhail 1:23:02 Right.

Dr. Rangan Chatterjee 1:23:03 Others-

Theresa MacPhail 1:23:04 Not so much

Dr. Rangan Chatterjee 1:23:04 ... two years later, they're still not the same, right? And again, so there's an individual change here. One thing I noticed, um, and this, well, you know, my son's 13 now, so when he was six months old and he was in a hospital in France, I really noticed then, back then at least, a big difference with how French doctors compared to the British doctors I was exposed to were dealing with things. And I, I, I, I really sensed, and I spoke to one of my, my buddies out there who's a d- who's a doctor in France, that in, in France, at least then, and this is just my... This is not a scientific paper. This is just my perception of what I saw. There was a real reluctance to give antibiotics without real hardcore proof that it was a bacterial infection, whereas my perception at that time was in the UK, it was a much more, um, freer-

Theresa MacPhail 1:24:04 Right

Dr. Rangan Chatterjee 1:24:04 ... the prescription. Let's put it like that, okay? And this was back in 2010.

Theresa MacPhail 1:24:08 Yeah.

Dr. Rangan Chatterjee 1:24:09 So culturally, I think there's a, um, culturally different doctors and, and healthcare professionals will practice differently, and they'll have more willingness or less willingness. And a question I always want patients to ask their doctors, which I don't think doctors encourage enough, and I don't think patients ask enough, and, and I, again, you know, I, I'm not having a go at patients.

Theresa MacPhail 1:24:32 Right.

Dr. Rangan Chatterjee 1:24:32 I wanna help them say, "Well, what happens if I do nothing here?"

Theresa MacPhail 1:24:35 Right.

Dr. Rangan Chatterjee 1:24:35 I think such an important question before you take anything, "What, what happens if I do nothing?" Because often, a doctor will give... And I get it. I've been in this position many times. You've got a busy clinic. You got four people waiting outside.

Theresa MacPhail 1:24:47 Exactly.

Dr. Rangan Chatterjee 1:24:47 There's a young child who's got evidence of an ear infection, right? They've got a fever. They've got a worried parent. And often societal pressure is that parent wants to get back to work as well bec- uh, and so you, you've got all these factors playing into that interaction. The easiest thing in the world is to do a prescription for an antibiotic.

Theresa MacPhail 1:25:07 Yeah. And they expect it, too, don't they?

Dr. Rangan Chatterjee 1:25:09 And they expect it.

Theresa MacPhail 1:25:10 Yeah.

Dr. Rangan Chatterjee 1:25:10 Yeah. But again, I don't want this to be about blame. It's, I think people expect it because that's been the conditioning-

Theresa MacPhail 1:25:16 That's right

Dr. Rangan Chatterjee 1:25:16 ... that bugs are bad. But a lot of these infections, and again, some are serious, they need to be treated.

Theresa MacPhail 1:25:23 Right.

Dr. Rangan Chatterjee 1:25:23 If they don't, they can be, you know, have long-term consequences for sure.

Theresa MacPhail 1:25:26 Right.

Dr. Rangan Chatterjee 1:25:26 But a lot of the time we're treating things where we could hold off a bit longer and go, "If this..." ... isn't better by this time, or if your fever goes above this, or if this symptom's happening, then think about it. But until then-

Theresa MacPhail 1:25:39 Right

Dr. Rangan Chatterjee 1:25:39 ... just try and manage it if you can. Because then if you think about adaptive and, um, immunity, you're the- you're also, your immune system's being trained and learning, isn't it?

Theresa MacPhail 1:25:49 Yeah, exactly. And I mean, they've started to try to do cultures also. So before prescriptions, they'll culture-

Dr. Rangan Chatterjee 1:25:57 Yeah

Theresa MacPhail 1:25:57 ... and see what bacteria is causing it, and if they're susceptible to... Because that's the other problem is, uh, of course, I'm sure you've discussed it on the show before, microbial resistance. So like antibiotic resistance is a big problem and a growing-

Dr. Rangan Chatterjee 1:26:13 Yeah

Theresa MacPhail 1:26:13 ... problem. And so that's, that's also part of this story, is that not only have we relied too much on antibiotics probably throughout the years, but so we've created a, a double-pronged problem. Like, we've got resistance, but then we've also got the situation where it's altering our gut microbiome-

Dr. Rangan Chatterjee 1:26:32 Yeah

Theresa MacPhail 1:26:32 ... considerably. And that barrier hypothesis. So the barrier hypothesis simply says that un- under normal circumstances, our barriers, so our skin, our intestinal tract, our nasal cavity, they are replete. They have their own ecosystems. They're finely balanced. And all things being the same, that our immune cells have a relationship with the things on them that actually is beneficial and provides a barrier. And if something happens to those barriers to make them more porous, so in the case of food allergy, you get food proteins, um, absorbed again in an intact form that your body's not used to. So, and one of... Like, for instance, something as simple as taking an antacid. So how many people are on-

Dr. Rangan Chatterjee 1:27:25 Mm

Theresa MacPhail 1:27:25 ... something for indigestion or, you know, taking a TUMS or something like that? And they've shown that if you're taking a prescription antacid, it's changing your gut microbiome, and it actually is, you know, you're decreasing the acid, which means your food isn't breaking up, which means it's getting-

Dr. Rangan Chatterjee 1:27:44 Yeah

Theresa MacPhail 1:27:44 ... absorbed in a more intact form that your immune system is freaking out about. So you're solving one problem and creating another. And so what do you do? Do you want the heartburn or do you want... [laughs]

Dr. Rangan Chatterjee 1:27:56 Yeah. Or, or there's a, there's a wider conversation here, which is, or do we need to think about these symptoms in a less reductive manner? Because, you know, I can tell you that the vast majority of cases with heartburn, if you know what to look for and if you have enough time to do this, you can find what's causing it.

Theresa MacPhail 1:28:16 Right.

Dr. Rangan Chatterjee 1:28:17 But because of the way the systems are in the medical system and, and the way we practice, it's easier to give an antacid or p- a PPI, a proton pump inhibitor-

Theresa MacPhail 1:28:26 Right

Dr. Rangan Chatterjee 1:28:26 ... which may initially help the symptoms.

Theresa MacPhail 1:28:30 Right.

Dr. Rangan Chatterjee 1:28:30 And then the problem is, and it, this I think all plays into allergies and autoimmune disease, is that, as you say, on one hand, you fix something, or you think you're fixing something.

Theresa MacPhail 1:28:39 Right.

Dr. Rangan Chatterjee 1:28:40 At least the patient has gone away. They're feeling better that they've got something, and symptoms are at least a little bit better.

Theresa MacPhail 1:28:46 Right.

Dr. Rangan Chatterjee 1:28:47 But all the initial studies on PPIs I think were four weeks maximum. You go into any GP practice in the country and see how many repeat prescriptions-

Theresa MacPhail 1:28:55 Right

Dr. Rangan Chatterjee 1:28:55 ... continuously for PPIs there are.

Theresa MacPhail 1:28:57 Yeah.

Dr. Rangan Chatterjee 1:28:58 It is staggeringly scary.

Theresa MacPhail 1:29:00 I've had a friend on them for about five years.

Dr. Rangan Chatterjee 1:29:02 Yeah.

Theresa MacPhail 1:29:02 Yeah.

Dr. Rangan Chatterjee 1:29:03 And the problem also is, is that then people think when they stop it and they get symptoms, they think, um, "Oh, no, I need the P- I still need the PPI." But the problem is you get rebound symptoms.

Theresa MacPhail 1:29:15 Right.

Dr. Rangan Chatterjee 1:29:16 So it's like an alcohol... It- it's not the same thing, but let me just draw the analogy. [laughs] If you're an alcoholic and you stop drinking, suddenly you're gonna get symptoms. You're gonna get shakes. You're-

Theresa MacPhail 1:29:27 Right

Dr. Rangan Chatterjee 1:29:27 ... Right? It doesn't mean that you needed the alcohol. It's a withdrawal symptom, [laughs] right?

Theresa MacPhail 1:29:34 Right.

Dr. Rangan Chatterjee 1:29:34 And you see this with PPIs. So people then stay on them longer, and it's not just allergies-

Theresa MacPhail 1:29:38 Right

Dr. Rangan Chatterjee 1:29:38 ... and absorption. You know, w- we know long-term PPI use is associated with vitamin B12 deficiency-

Theresa MacPhail 1:29:44 Right, right

Dr. Rangan Chatterjee 1:29:44 ... because you need acid to absorb B12. So I, I think this all plays into the topic we're talking about. The, the health of the gut microbiome is really, really important. So as we learn more, we need to do better as doctors, as society. I wonder if we just tackle this in two different ways though, Theresa, because I wanna make sure we, we at least come up with... You know, we, we can't go through everything in the book-

Theresa MacPhail 1:30:08 No

Dr. Rangan Chatterjee 1:30:08 ... frankly. It is so thorough.

Theresa MacPhail 1:30:10 [laughs]

Dr. Rangan Chatterjee 1:30:10 But, um-

Theresa MacPhail 1:30:12 Can I just actually-

Dr. Rangan Chatterjee 1:30:13 Please, yeah

Theresa MacPhail 1:30:13 ...

Theresa MacPhail 1:30:13 can I, I just talk about stress?

Dr. Rangan Chatterjee 1:30:17 Yeah.

Theresa MacPhail 1:30:17 [laughs]

Dr. Rangan Chatterjee 1:30:18 Well, I, I wanna... Yeah. Well, let's go into stress.

Theresa MacPhail 1:30:21 Yeah. Uh, bec- because we're talking about proton pump inhibitors, and can we just talk about the relationship between acidity in the stomach and stress? And, you know, like, stress has certain effects on our bodies. And, a- and one of the experts I talked to, Dr. Peter Lio, said, "You can absolutely..." He's an eczema specialist. And he said, "You can absolutely track when someone is experiencing greater levels of stress in their daily life, their skin changes."

Dr. Rangan Chatterjee 1:30:50 Mm-hmm.

Theresa MacPhail 1:30:51 I mean, you... It's a one-to-one. You can see the microbiome and the skin porosity change, and obviously, it has an effect on the gut microbiome as well. And so we're living quite stressful lives, right? I mean, most of us are worried about making ends meet or childcare or-

Dr. Rangan Chatterjee 1:31:09 Yeah

Theresa MacPhail 1:31:09 ... you know, taking care of elderly patients. Like, what, what, what... Elderly patients. Elderly parents.

Dr. Rangan Chatterjee 1:31:14 And elderly patients. [laughs]

Theresa MacPhail 1:31:15 And elderly patients, which there are more and more of every day. So those stressors affect your immune system.

Dr. Rangan Chatterjee 1:31:23 Yeah.

Theresa MacPhail 1:31:23 So it's not just the outside world, as in pollen or dust mites or food proteins. It's also The outside world in terms of the social pressures and economic stressors that are changing our biology as well, because-

Dr. Rangan Chatterjee 1:31:40 Mm

Theresa MacPhail 1:31:40 ... you know, it's changing, uh, the way we respond. And, and so the immune system is so finely tuned that hormonal changes, stress, any sleep, nutrition, I mean, anything can change it.

Dr. Rangan Chatterjee 1:31:56 We'll be back to the conversation in just a moment. Now, many of us struggle to find time to eat all of these incredible whole foods. That's why I'm a big fan of good quality whole food supplements like this one that's been in my own life for over three years now. It contains over 75 whole food source ingredients, vitamins, minerals, pre and probiotics, and can help us support our energy, focus, digestion, and our immune system. Athletic Greens are giving my audience a fantastic offer, one year's free supply of vitamin D and five free travel packs with your first order. You can see all the details at athleticgreens.com/livemore, or simply click on the link below. Now, back to the conversation.

Theresa MacPhail 1:32:43 And so you'll often have people say, "Well, last year or last month, my symptoms weren't as bad." Well, maybe your stress level changed, or, you know, women experiencing pregnancy or menopause will have sudden new allergies that they didn't have before because there's a huge effect-

Dr. Rangan Chatterjee 1:33:00 Mm

Theresa MacPhail 1:33:00 ... of hormones on these systems. So it's just, it's such an intricate web, and I, I think to go back to that point of this is really a social problem. That's obviously a social problem.

Dr. Rangan Chatterjee 1:33:11 Mm-hmm.

Theresa MacPhail 1:33:11 Like, the way you respond to stress, sure, it's an individual biological concern, but how can we escape stress? Like, where are we gonna go? Are we gonna-

Dr. Rangan Chatterjee 1:33:21 Yeah

Theresa MacPhail 1:33:21 ... live on a mountaintop, cut off from everything? [laughs]

Dr. Rangan Chatterjee 1:33:26 Yeah, and, and this is where it becomes a vicious cycle, doesn't it? Because the allergy sufferer who's not taken seriously feels frustrated that the world around them doesn't get how bad it is for them.

Theresa MacPhail 1:33:39 Right.

Dr. Rangan Chatterjee 1:33:40 They're tired, they're irritable. They don't sleep as well because they're itchy, which makes them more tired, more irritable, less empathetic, because we know a lack of sleep decreases your empathy.

Theresa MacPhail 1:33:52 Right.

Dr. Rangan Chatterjee 1:33:55 And then we know that a lack of sleep is a stressor on the body.

Theresa MacPhail 1:33:59 Right.

Dr. Rangan Chatterjee 1:34:00 Right? It's a stressor on the immune system.

Theresa MacPhail 1:34:02 Yeah.

Dr. Rangan Chatterjee 1:34:02 So it really is quite a toxic, vicious cycle when someone has got unmanaged allergies, an inability to get on top of it. It can affect their relationships, it can affect their health, it can affect their happiness. In fact, you outline some of the research in the book whereby I think the relationship between increase in allergies and an increase in mental health problems, but also the other way around.

Theresa MacPhail 1:34:28 Right.

Dr. Rangan Chatterjee 1:34:28 So an increase in mental health problems like anxiety and depression can also increase allergies, which is really, really interesting.

Theresa MacPhail 1:34:34 Yeah, and there seems to be, if you do studies in people who have even mild allergies, it tends to track with greater levels of anxiety and depression. But again, it's, yeah, it's constantly losing sleep, it's constantly not feeling your best, your immune system is constantly on, and that eventually will take an emotional toll, a mental toll. And so it's a bit the chicken and the egg, like what's causing what. It's hard to tear that apart and look at it.

Dr. Rangan Chatterjee 1:35:03 The problem often with stress is, and I think we as a profession have to take a bit of responsibility for this, sometimes the way we've communicated it to our patients makes them think that we're not taking them seriously.

Theresa MacPhail 1:35:17 Right.

Dr. Rangan Chatterjee 1:35:17 Makes them think that, oh, they're just trying to fob me off, and put it down to stress. But stress is real. Stress has real biological and physical effects on the body, right? And you show in the section, Stress, in the book, stress impacts allergies via the histamine released from mast cells.

Theresa MacPhail 1:35:36 Right. So your mast cells are really sensitive.

Dr. Rangan Chatterjee 1:35:39 Yeah.

Theresa MacPhail 1:35:39 And they will respond to higher stress hormones or chemicals in your system and release histamine, which is a stress response. I mean, like I said, mast cells only res- release histamine when they feel stressed. [laughs] So when they are feeling dam- when, either when they get damaged or when-

Dr. Rangan Chatterjee 1:36:03 Yeah

Theresa MacPhail 1:36:03 ... they are feeling under threat, they will release histamine. So y- your body thinks it's... Histamine is, is like a red flag for your body.

Dr. Rangan Chatterjee 1:36:14 Yeah.

Theresa MacPhail 1:36:14 So it is not a, a nice experience. It doesn't turn on good things.

Dr. Rangan Chatterjee 1:36:20 And there's some now studies, I think, showing that mindfulness and meditation can help reduce severity of eczema symptoms-

Theresa MacPhail 1:36:27 Yeah

Dr. Rangan Chatterjee 1:36:27 ... and, and how many flares. And once you understand the biology of the immune system and stress' impact on it, it's like, yeah, of course, that makes sense.

Theresa MacPhail 1:36:35 Right. [laughs]

Dr. Rangan Chatterjee 1:36:35 Right? It's not just-

Theresa MacPhail 1:36:36 Right

Dr. Rangan Chatterjee 1:36:36 ... this fob off, it's actually, no, this is, this is real. It may not be the whole picture, but it may be part of the picture.

Theresa MacPhail 1:36:43 It's definitely part of the picture, and in fact, in India, um, a researcher I talked to there who specializes in asthma often prescribes yoga for her patients, and the reason she does so is, uh, it calms the immune system, and also it trains them how to breathe. And so when they go into an asthma attack-

Dr. Rangan Chatterjee 1:37:06 Mm

Theresa MacPhail 1:37:06 ... they kind of naturally understand how to control their breath. And so she finds that the de-stressing helps, but also the breathing techniques help. So she will-

Dr. Rangan Chatterjee 1:37:18 Yeah

Theresa MacPhail 1:37:18 ... assign that in, in conjunction with giving them an inhaler. So she kind of tries to tackle the problem holistically rather than just treating the biological symptoms.

Dr. Rangan Chatterjee 1:37:31 And I think the only way we're really [laughs] going to get on top of people's allergies, or at least help them be manageable and improve their quality of life- ... is by taking this rounded, holistic approach. So, if we think about things that we can do for just a moment. So, you've sort of walked us through the hygiene hypothesis, the barrier regulation hypothesis, I think that Catherine Nagler talks about-

Theresa MacPhail 1:37:56 Right

Dr. Rangan Chatterjee 1:37:57 ... the we are doing it to ourselves hypothesis-

Theresa MacPhail 1:37:59 [laughs]

Dr. Rangan Chatterjee 1:37:59 ... that we are literally covering throughout this entire conversation, this idea that fundamentally though, what's the interface between us and our outside world? It's through our microbiome largely, isn't it? It's a huge part of it, at least, so-

Theresa MacPhail 1:38:14 It's our cells, our immune cells, plus the microbiome.

Dr. Rangan Chatterjee 1:38:18 Yeah.

Theresa MacPhail 1:38:18 So, and we don't really understand the conversations that they're having-

Dr. Rangan Chatterjee 1:38:22 Yeah

Theresa MacPhail 1:38:22 ... if that makes sense. We don't really understand their interconnection and what components are crucial to that conversation going well. And then you have the external things coming into contact with... I mean, it's interesting because I consider, like, one of the changes for me writing this book is I consider those microbes me, if that makes sense.

Dr. Rangan Chatterjee 1:38:46 Mm-hmm.

Theresa MacPhail 1:38:46 Like, they're me. [laughs] I- without them, I would literally be unable to survive. And so I've just changed my thinking. So the external things, so I'm touching this table, the microbes on my hands are still me, so they're, both my cells and them are coming into contact with the cells of this table-

Dr. Rangan Chatterjee 1:39:09 Yeah

Theresa MacPhail 1:39:09 ... whatever is on there. And it's trying to understand that connection-

Dr. Rangan Chatterjee 1:39:14 Yeah

Theresa MacPhail 1:39:14 ... about like how they are working together to switch things on and off in relationship to the things we are encountering.

Dr. Rangan Chatterjee 1:39:22 Yeah. It, it's, it's just fascinating, this idea that we have more microbial cells in our body than human cells. I think that's been one of the big aha-

Theresa MacPhail 1:39:32 [laughs] Right

Dr. Rangan Chatterjee 1:39:33 ... kind of realizations over the last five, 10 years of microbiome research.

Theresa MacPhail 1:39:36 Yeah.

Dr. Rangan Chatterjee 1:39:37 Um-

Theresa MacPhail 1:39:37 I heard someone that studies the microbiome, uh, just the other day say that it's like there was an organ we didn't know-

Dr. Rangan Chatterjee 1:39:43 Yeah

Theresa MacPhail 1:39:43 ... existed [laughs] until 10 years ago. [laughs]

Dr. Rangan Chatterjee 1:39:46 Yeah. A whole organ.

Theresa MacPhail 1:39:47 Yeah. Yeah.

Dr. Rangan Chatterjee 1:39:47 And it weighs, I think, maybe as much as the brain-

Theresa MacPhail 1:39:49 Right. [laughs]

Dr. Rangan Chatterjee 1:39:50 ... I think. It's, it's pretty profound.

Theresa MacPhail 1:39:52 Yeah.

Dr. Rangan Chatterjee 1:39:52 And I, I think it's also r- really interesting if we think about our relationship with our surroundings, most mast cells that we've been talking about throughout this conversation, the mast cells, of course, are what release histamine, that give us a lot of the symptoms we associate with allergy, itching, redness, you know, stuffiness, whatever it might be. The highest concentration are at the, the three areas where we interact with the outside world-

Theresa MacPhail 1:40:16 Right

Dr. Rangan Chatterjee 1:40:16 ... right? In our guts-

Theresa MacPhail 1:40:18 Yes

Dr. Rangan Chatterjee 1:40:18 ... 'cause that interacts with food from the outside world. In our respiratory tract-

Theresa MacPhail 1:40:22 Yes

Dr. Rangan Chatterjee 1:40:22 ... lungs, nasal cavity, where that interacts with things that we inhale from the outside world, and then also under our skin, 'cause that's obviously interacting with the outside world the entire time.

Theresa MacPhail 1:40:32 Right.

Dr. Rangan Chatterjee 1:40:32 So then if we say that the barriers are important, what are the things that we can do then to support those barriers?

Theresa MacPhail 1:40:44 I think it's trying to re-engineer our brains to stop associating automatically microbes with negative, bad things. So germ theory did a lot for us, but unfortunately, it made all germs into enemies. [laughs]

Dr. Rangan Chatterjee 1:41:05 Mm-hmm.

Theresa MacPhail 1:41:05 And I think I try to make decisions for everyone now. [laughs] So I think of myself as a, a confederation, if you like. And so I think about, all right, do I really need that hand sanitizer? Or even simple things like, you know, nobody ever thinks about this, but if you use a dishwasher, like, I get it, it's easier, um, it's, you know, water efficient. But those, the detergents we're using in them and the heat destroy all the leftover bacteria that you have on dishes from food and just from you eating that are actually beneficial. It's like, uh, well, if you wash, hand wash a dish, enough bacteria stays on there, and you get most of it off, but like a little bit stays on, and it turns out a little bit is good. So I try to make those decisions. So I'll hand wash my dishes versus throwing them in the dishwasher. Or, so I'm just constantly thinking not just about what's easiest for me and what do I want, but what do the things in me and on me want, and it's not to be constantly stripped away. Like-

Dr. Rangan Chatterjee 1:42:22 Yeah

Theresa MacPhail 1:42:22 ... if you think especially about our skin, like the amount of stripping that we do, like in the shower, scrubbing, scrubbing, scrubbing with-

Dr. Rangan Chatterjee 1:42:31 Yeah

Theresa MacPhail 1:42:31 ... the harsh soaps, and, uh, you know, you're destroying whole communities. I, I sound like I'm talking about the Whos from Whoville, but it is a little bit like that-

Dr. Rangan Chatterjee 1:42:40 Yeah

Theresa MacPhail 1:42:40 ... that whole worlds exist on us that we are impacting without even thinking about it. So I just think we all need to, A, do more research on, we really don't understand this world at all. Like, we do not understand... I mean, we're not even sure exactly what is in our guts.

Dr. Rangan Chatterjee 1:42:59 Yeah.

Theresa MacPhail 1:42:59 It, like, we, I mean [laughs] I- so they'll do, like, genetic typing of things in our guts, and we'll see gene sequences that are not recognizable. Like, and so we don't even know what's there.

Dr. Rangan Chatterjee 1:43:10 But, but, but we do know what's, we know a lot about what's damaging them, don't we?

Theresa MacPhail 1:43:14 Yes. Right, right.

Dr. Rangan Chatterjee 1:43:15 So I think that's the empowering piece, is there's a lot we can't change-

Theresa MacPhail 1:43:19 Right

Dr. Rangan Chatterjee 1:43:19 ... about society, for sure. But, you know, I don't know how many people are gonna use their dishwasher less on the back [laughs] of what we're saying about how stressful life is and how busy people are, right?

Theresa MacPhail 1:43:29 I know, yeah. Impossible.

Dr. Rangan Chatterjee 1:43:30 Because, because-

Theresa MacPhail 1:43:30 Yeah. [laughs]

Dr. Rangan Chatterjee 1:43:31 ... you might be increasing your stress levels somewhat.

Theresa MacPhail 1:43:33 Yeah.

Dr. Rangan Chatterjee 1:43:33 But just to start, I think what's empowering is just to start thinking about these things and going, "Okay, well, what products am I buying?"

Theresa MacPhail 1:43:42 Right.

Dr. Rangan Chatterjee 1:43:42 Right? What's in them? Are, is it full of... You can get more natural, kinda less toxic- ... products to use, right?

Theresa MacPhail 1:43:51 Yes, you can. But again, they're expensive

Dr. Rangan Chatterjee 1:43:53 E- exactly. So for people who can afford it, right, and have the resource to do that, that is one thing you can do immediately.

Theresa MacPhail 1:44:01 Yes. Eat the skin on fruits-

Dr. Rangan Chatterjee 1:44:03 Yeah

Theresa MacPhail 1:44:03 ... and eat the potato skin. Like, try to think, "Okay, am I g- am I giving the microbes in my gut what they want to eat, which is maybe not what I want to eat?" So [laughs] you know, I, forcing myself to have more broccoli, you know? Like, but really and truthfully, that is important to think about feeding them, because they're feeding you.

Dr. Rangan Chatterjee 1:44:24 What about the pesticides that are used-

Theresa MacPhail 1:44:28 Oh

Dr. Rangan Chatterjee 1:44:28 ... on fruits and vegetables these days?

Theresa MacPhail 1:44:31 Right. I mean, that is another whole kit and caboodle, because not onl- you're introducing more chemicals.

Dr. Rangan Chatterjee 1:44:37 I just love that phrase. That's a whole [laughs]

Theresa MacPhail 1:44:39 Kit and caboodle. [laughs]

Dr. Rangan Chatterjee 1:44:40 Kit and caboo- I love that. I don't know that one.

Theresa MacPhail 1:44:43 Yeah. [laughs]

Dr. Rangan Chatterjee 1:44:43 But I can infer the meaning from the way you said it. [laughs]

Theresa MacPhail 1:44:47 Yeah, it's just a whole mess that, you know, you're introducing all these, again, some of those chemicals your body would never have seen, and yet, you know, s- the way we produce food is very different. Like, the way we grow food is different, and that's all having, I'm sure, ancillary run-on effects. For sure we know we're getting too much sugar, too much fat. I'm sure you've talked about that 1,000 times on this podcast, and that's feeding the bad bacteria, so to speak, or it's imbalancing anyway. Like, it's, it's, it's basically creating a situation in your gut where you have some microbes that are flourishing with all the extra fat and sugar, but you're starving the ones that need-

Dr. Rangan Chatterjee 1:45:29 Mm-hmm

Theresa MacPhail 1:45:29 ... the skin on the apple, that need more kale. Like [laughs]

Dr. Rangan Chatterjee 1:45:33 Yeah.

Theresa MacPhail 1:45:34 And so I try to make... We can all do better in that way, and think about less processed foods, like trying to get food delivery to people in more whole forms. And-

Dr. Rangan Chatterjee 1:45:45 Ho- have, have you found from talking to these, uh, allergy experts around the world that this stuff, when we do, can make a difference to people's-

Theresa MacPhail 1:45:53 Yeah

Dr. Rangan Chatterjee 1:45:53 ... allergy symptoms?

Theresa MacPhail 1:45:54 Especially in the early, like, again, in that early crucial period when you're, you're dealing with children, like, trying to give their immune systems-

Dr. Rangan Chatterjee 1:46:02 Yeah

Theresa MacPhail 1:46:02 ... the best help that you can. So-

Dr. Rangan Chatterjee 1:46:05 So I definitely get that, the, you know, for people who are, let's say, let's say there's a pregnant, uh, lady listening to this right now, this is great information for her-

Theresa MacPhail 1:46:14 Right

Dr. Rangan Chatterjee 1:46:14 ... to know going into, uh, the first two or three years, okay, these are really important.

Theresa MacPhail 1:46:19 Right.

Dr. Rangan Chatterjee 1:46:20 What can I do here? Okay, but there's many of us who, uh, f- through no fault of our own, didn't have that, or maybe-

Theresa MacPhail 1:46:27 Right

Dr. Rangan Chatterjee 1:46:27 ... had a load of antibiotics for ear infections when we were-

Theresa MacPhail 1:46:29 Yeah

Dr. Rangan Chatterjee 1:46:29 ... little, or whatever it might be, or had a cesarean, for very good reasons. So maybe didn't get the best start.

Theresa MacPhail 1:46:36 Right.

Dr. Rangan Chatterjee 1:46:37 I'll tell you my own experience, 'cause I've seen a lot of allergy patients, uh, in one of my clinics over the last few years, and I have found that when you take a multifactorial approach, you're not looking for one smoking gun. When you try and reduce the toxic load on these barriers, right? So, you know, helping people to clean up their diets compared to what it is.

Theresa MacPhail 1:46:58 Right.

Dr. Rangan Chatterjee 1:46:58 You know, reducing their exposure to various toxic inputs. Um, you know, helping them have less stress in their life, right? Which can be hard, but there are also things that can be done.

Theresa MacPhail 1:47:11 Yeah, of course.

Dr. Rangan Chatterjee 1:47:12 And maybe supporting their gut microbiome, potentially, with dietary changes or whatever. You, you can see a marked decrease, not in everyone, but with many you can.

Theresa MacPhail 1:47:23 Yes.

Dr. Rangan Chatterjee 1:47:24 But it's very rarely, in my experience, just one thing.

Theresa MacPhail 1:47:27 Right, exactly. Because, I mean, all of those theories... W- so I would ask people, so I interviewed, you know, just dozens and dozens of the top experts on these issues, and top researchers, and I would ask them, "If I forced you to choose what is causing allergies, what would you say?" 'Cause I just wanted to get a lay of the land, and all of them refused to answer that question, and said the following: "It's everything. It's everything we're doing." They wouldn't come down on a side, because it is, our bodies are getting bombarded from all angles, so our immune systems are just getting overwhelmed at every point of entry. And so it is all of the things we're doing. It is the dishwashers, it is the detergents, it is the, you know, using, um, non-cloth diapers. It's, you know, i- increasing levels of CO2 in the air that is producing multitudes of pollen, pumping out more, um, particulate matter, so that's irritating our lungs. Uh, it's all of it. And so if you try to tackle this from just... So people are... I often feel bad, because when you read this book, um, one of the things I thought about was, like, w- well, God, it's kind of... It's not depressing, but there's no easy solution. Like, if you pick up my book and you think at the end, it's gonna be like, "Here's how you're gonna get rid of your allergies," you're gonna be so disappointed [laughs] because it requires a big societal shift in how we're doing things.

Dr. Rangan Chatterjee 1:48:56 Yeah, I'm... Look, I don't think they're gonna be disappointed, because if you're looking for a quick fix, you know, "What's the thing I haven't heard about yet that if I start taking is gonna get rid of these?" then I think you're gonna be disappointed.

Theresa MacPhail 1:49:07 Right.

Dr. Rangan Chatterjee 1:49:07 If you're looking to understand it better and to figure out, "Ooh, uh, god, that could apply to me. Can I reduce that exposure? That, oh, th- you know, that's probably not relevant for me, but that bit is," I think it's quite empowering to help people build up a picture around certain things that they can potentially change. I mean, one thing we've not mentioned yet, really, is diesel-

Theresa MacPhail 1:49:30 Yes

Dr. Rangan Chatterjee 1:49:31 ... and, uh, particulate matter, and even this idea that, um, particulate matter, so diesel fumes, can make allergies worse. So it's not necessarily that we're allergic to the diesel fume or-

Theresa MacPhail 1:49:43 No, not at all

Dr. Rangan Chatterjee 1:49:44 ... but it's a, it's doing something to the allergens. Could you maybe just touch on that?

Theresa MacPhail 1:49:48 Well, it's irritating to our lungs. Like, you know, those particles are not- I mean, they're foreign, and our immune systems are not excited about them being there

Dr. Rangan Chatterjee 1:49:56 Diesel more than petrol?

Theresa MacPhail 1:49:58 Uh, yeah, so d- diesel exhaust... So, like, what we're talking about here is ultra-fine particulate matter. So most places only measure, it's 2.5 microns to 10 microns. And just to give people a sense of what we're talking about, a red blood cell is five microns in diameter. So we're talking about particles that can be as small as one micron. And so their ability to get deeply into our lungs, so when you think about that small of a particle and you're inhaling, it's able to just go much deeper into the lung cavity. And what they've found is that pollen will attach themselves to these particulate matters, so they get kind of glommed up. And so when you're breathing in, the pollen is actually going a little bit deeper and causing more of a problem. And the same thing happened, they think, one of the theories is that if you look at COVID rates during the pandemic, they could fluctuate, but about 40% of the fluctuations w- could be correlated to the amount of pollen in the air. Because the, uh, also the virus is able to attach to particulates and pollen, and so you're just, you're inhaling these particles and depositing. It's almost like the pollen is getting an Uber lift or a cab lift deeper into your lungs.

Dr. Rangan Chatterjee 1:51:26 Do we know in the early COVID lockdowns, when in many countries or many urban environments travel stopped massively or, or, or was greatly reduced, for some people. Clearly many workers, it wasn't reduced for them

Theresa MacPhail 1:51:44 Right

Dr. Rangan Chatterjee 1:51:44 ... um, but we know that levels of pollution came down significantly. Now, on one hand, levels of pollution are coming down, which is a good thing. On the other hand, stress and fear is going up.

Theresa MacPhail 1:52:00 Correct.

Dr. Rangan Chatterjee 1:52:00 Uh, sprays and, um, hand cleaning and toxic substances is going, you know, is going up, right?

Theresa MacPhail 1:52:07 Yes.

Dr. Rangan Chatterjee 1:52:07 So do we know when we look back now, were people complaining less of allergic symptoms-

Theresa MacPhail 1:52:15 Yes

Dr. Rangan Chatterjee 1:52:15 ... at that time?

Theresa MacPhail 1:52:16 Well, the interesting thing is is so all I have is anecdotal data.

Dr. Rangan Chatterjee 1:52:20 Okay.

Theresa MacPhail 1:52:20 So nobody was really... I mean, we were all so stressed out and just trying to cope with the pandemic that not many people were like, "Aha, let me do a study on allergies during this event." But [laughs]

Dr. Rangan Chatterjee 1:52:29 And who's going to their doctor to report allergies-

Theresa MacPhail 1:52:31 Right [laughs]

Dr. Rangan Chatterjee 1:52:31 ... at that time as well, right?

Theresa MacPhail 1:52:33 Yeah, exactly. Exactly. But I have heard from researchers and clinicians who, especially with asthma patients, they had less episodes. So they were using their inhaler less frequently, and they, in general, felt better throughout that period. And because people were masking, remember for that brief time they, people were masking also outside, and so the masks were, the theory is that perhaps also they were obviously filtering out pollen. So people were just reporting a lot less respiratory symptoms throughout that period. But I have to do a little comma, but if you were allergic to dust mites or an internal allergen, it went up. So-

Dr. Rangan Chatterjee 1:53:19 When you say internal, do you mean inside the house?

Theresa MacPhail 1:53:21 Inside the house.

Dr. Rangan Chatterjee 1:53:22 Because that's another thing. When we think about pollution, we're thinking about-

Theresa MacPhail 1:53:25 Outside

Dr. Rangan Chatterjee 1:53:25 ... outside, bus fumes, diesel fumes, car fumes, airplanes-

Theresa MacPhail 1:53:29 Right

Dr. Rangan Chatterjee 1:53:29 ... right? But actually, sometimes indoor air can be worse than outdoor air.

Theresa MacPhail 1:53:33 Absolutely. Right. And so that's what they found, that if you suffered from, like, a pollen allergy or a pollen, uh, trigger for your asthma, or you, a- and you were just getting cleaner air, that your asthma events went down, probably because a combination of mask use and less particulate matter. But if you had an allergy to dust mites or dust or anything that w- could be found indoors circulating, then you had no protective effect, and f- and in fact might have gotten a bit worse because you're spending more time inside with your dust mites. [laughs]

Dr. Rangan Chatterjee 1:54:09 What's really interesting for me is when you were supporting your we are doing it to ourselves hypothesis, you, you brought up the case that pets that we... You brought up that animals that we've domesticated, so pets, dogs, cats, I think you said some horses-

Theresa MacPhail 1:54:25 Yes, horses

Dr. Rangan Chatterjee 1:54:26 ... are also now displaying an increase in allergies, whereas the animals who are still in the wild maybe are not so. Again, supporting this idea that there's something about our human environments that is causing this, which I found really, really interesting.

Theresa MacPhail 1:54:43 I mean, it's really fascinating. So I went to speak to some, uh, veterinarians at Cornell Veterinary School, which is one of the best veterinary schools probably in the world, and they said that they've absolutely seen an explosion of allergies in pets. And it's under-diagnosed and-

Dr. Rangan Chatterjee 1:55:03 Mm

Theresa MacPhail 1:55:03 ... bec- and under-surveyed. So they really don't have great numbers for me. Like, I said, "What, what's the picture look like?" And they said, "We can't really tell you, but we can tell you just based on our own practice and what we're hearing around the country." And the symptoms are very similar to us. So in dogs, it's itch, so they're scratching a lot, like obsessively, and, and having open sores. In cats, it's asthma [laughs] actually a lot, so they're sneezing and coughing. Also, a little bit of itch. In birds, our pet birds-

Dr. Rangan Chatterjee 1:55:33 Mm

Theresa MacPhail 1:55:33 ... it's itch and coughing. And in horses, it's itch and coughing. There is some evidence that pigs and, and cows are also developing allergies, and there's no evidence that a deer or a fox or, or anything out there living its own life away from us have them. So obviously- The things that are happening to our immune system are also happening to the immune systems-

Dr. Rangan Chatterjee 1:56:01 Yeah

Theresa MacPhail 1:56:01 ... of the things that live our exact same lifestyles. One of the most compelling points for me is that often if they can find the trigger, which sometimes they can't, a lot of the times it's their food. So w- if you think about it, we have changed our pets' diets also [laughs] . Right? I mean, we, we-

Dr. Rangan Chatterjee 1:56:24 We're not content to just screw it up for ourselves.

Theresa MacPhail 1:56:26 [laughs] Right. Yeah. So we're opening a can of manufactured food, and we're feeding them.

Dr. Rangan Chatterjee 1:56:33 Yeah.

Theresa MacPhail 1:56:33 And so we could be disrupting their microbiomes because all animals have i, I mean, similar immune systems. And so obviously, whatever is happening to them is a reflection of what's happening to us, and that to me is some of the biggest evidence that we are definitely doing this.

Dr. Rangan Chatterjee 1:56:51 Yeah. And, and there's stuff, you know, we, we haven't gone deep into these, these chemicals, but it's in carpets, in paint, in, um, in our sofas.

Theresa MacPhail 1:57:00 Yes.

Dr. Rangan Chatterjee 1:57:00 Like, it's, there's so much now, like the stuff that's put in for, to make things fire repellent.

Theresa MacPhail 1:57:05 Right.

Dr. Rangan Chatterjee 1:57:06 Right? On one, on one hand, great, right?

Theresa MacPhail 1:57:08 Right.

Dr. Rangan Chatterjee 1:57:08 There's a benefit. On the other hand, potential negative effects on people who are susceptible, and it's, it really is quite baffling and bamboozling when you start trying to get into this, 'cause of course, as we mentioned, there is a cost element. But-

Theresa MacPhail 1:57:23 Right

Dr. Rangan Chatterjee 1:57:24 ... I think just as we're coming towards the end of this conversation, I have usually seven or eight different factors that I'm looking at with patients with chronic health issues that I think, uh, cause them, uh, and can also potentially be manipulated and changed, right? So if I think about them through the lens of what you've written about in your book and what we're talking about with respect to allergies, okay, let's start off with what I call these four pillars of health, okay? Food, movement, sleep, and stress. And let's look at them through the lens of allergies and the fact that we're trying to support our microbiomes and our immune system and our barriers wherever we can. Okay, so what can we do with foods? Well, it's advice people have heard before, but it's, it's, it's worth reiterating, right?

Theresa MacPhail 1:58:12 Right.

Dr. Rangan Chatterjee 1:58:13 F- as much as you can, whole foods, fresh foods if you can, you know, diversity-

Theresa MacPhail 1:58:18 Yes

Dr. Rangan Chatterjee 1:58:18 ... if you tolerate that. Try and reduce your intake of modern food-like products, ultra-processed foods. Basically, try and eat in a way that supports your gut microbiome. Would you agree with that?

Theresa MacPhail 1:58:30 Yes, absolutely, and it's closer to the way we would've eaten in the past.

Dr. Rangan Chatterjee 1:58:34 Yeah, so that, the, the- these old sort of maxims like eat like your great-grandparents sort of eat-

Theresa MacPhail 1:58:39 Right

Dr. Rangan Chatterjee 1:58:39 ... and that sort of thing. Okay, so that's something practical we can do around foods. Okay, then let's go to exercise. Okay, we've not really discussed physical activity in relation to this. Um, I guess if I think about air pollution, and I think about-

Theresa MacPhail 1:58:53 [laughs]

Dr. Rangan Chatterjee 1:58:53 Okay, try and be careful when you're going, you know, for your walks, you know, if you've got a park or a forest to get to, that's probably gonna be better, but-

Theresa MacPhail 1:59:03 Right

Dr. Rangan Chatterjee 1:59:03 ... you know, still move your body as much as you can. And I know actually in India, I believe that there's certain advice in, in certain countries to, to walk, go for your walk at, at times when pollution, air pollution is lower-

Theresa MacPhail 1:59:17 Right. Yes

Dr. Rangan Chatterjee 1:59:18 ... which I find really interesting.

Theresa MacPhail 1:59:19 Yes. That makes complete sense. And, and try to stay away from busy roadways.

Dr. Rangan Chatterjee 1:59:24 Yeah. So again, that's something practical that that's gonna lower the load on the immune system. Okay, stress. We've mentioned already in this conversation how, uh, negative stress can be for our immune system and for allergies, so you know, there's all kinds of things people can do. Uh, I've done many podcasts so far on stress, and whether it's meditation or breathing exercises or journaling, whatever it might be, that is also potentially going to, to help, right?

Theresa MacPhail 1:59:51 Absolutely. I mean, if you can even decrease the stress a little bit, and I, if, I forgot to mention it, but you know, it's also helpful for the parents of allergic children to decrease their stress. I mean, I don't know if people know this, but the parents of someone with a severe allergy have the stress levels of someone who just had a recent heart attack.

Dr. Rangan Chatterjee 2:00:14 Wow.

Theresa MacPhail 2:00:14 Like, it is a massive stress on not just the child or whoever is, um, experiencing the allergy, but for the entire family.

Dr. Rangan Chatterjee 2:00:24 Yeah. That is, that's so enlightening, and I can already think of people in personal life and professional life where, where you can totally see that.

Theresa MacPhail 2:00:34 Mm-hmm.

Dr. Rangan Chatterjee 2:00:35 Um, so reduce stress as much as we can. Uh, that fourth pillar, sleep, of course, if you're itchy and allergic, it is hard. But you know, even just that idea that prioritizing my sleep as much as possible is going to have a meaningful effect on my allergies and how much I get bothered by them, how irritated I am, potentially how itchy, how s- how many symptoms I get. So that's, th- I think that's helpful around those four pillars. And then some of the other things which I think are worth talking about, I always think about sunlight and vitamin D.

Theresa MacPhail 2:01:07 Yes.

Dr. Rangan Chatterjee 2:01:07 Right? I know you do cover that in the book. I know we don't have long, so, um, quick overview on, on vitamin D and outdoor living and its relevance for allergies.

Theresa MacPhail 2:01:18 They think there's a connection. It, it's not quite clear, but there does seem to be a correlation between lower levels of vitamin D and immune function. I mean, we know that th- that's there, but it clearly must have an effect on allergies as well. So just making sure that you're outdoors in the sunlight more and, and getting more vitamin D to support the basic immune health-

Dr. Rangan Chatterjee 2:01:41 Yeah

Theresa MacPhail 2:01:41 ... is gonna obviously have a knock-on effect for allergies.

Dr. Rangan Chatterjee 2:01:45 Exactly, and my approach with patients is I always will try and optimize their vitamin D levels, even if there's no trial to say, do this on an allergic patient. I think there are some supported data anyway on that, but it's again, this whole idea that there are multiple inputs going on. Let me try and optimize what I can. I can't optimize everything, but what I can. Okay, the next one for me is always pharmaceutical drugs. Could there be any drugs that we're using and taking that could be negatively impacting our microbiome? And so of course, we mentioned PPIs, proton pump inhibitors and antacids. Again, maybe people can have a conversation with their doctor or healthcare professional if it's something they wanna try and get off potentially. We mentioned just to be cautious with antibiotics.

Theresa MacPhail 2:02:29 Right

Dr. Rangan Chatterjee 2:02:29 Um-

Theresa MacPhail 2:02:30 As much as you can-

Dr. Rangan Chatterjee 2:02:31 As much as you can

Theresa MacPhail 2:02:31 ... tolerate, I mean, the, the g- golden advice is, you know, if something extends past a week, that's a problem. People are just, they wanna feel good as quickly as possible, so they go to their doctor on day three of being ill. And a virus takes about seven days to clear.

Dr. Rangan Chatterjee 2:02:49 Yeah.

Theresa MacPhail 2:02:49 So if you can just be a little bit more patient and go to the doctor later, you're kind of taking away some of the chances that you're gonna get an antibiotic that you don't need.

Dr. Rangan Chatterjee 2:02:59 Yeah. And ask, "What happens if I do nothing?"

Theresa MacPhail 2:03:02 Right.

Dr. Rangan Chatterjee 2:03:03 You know? And we have something in the UK called delayed prescriptions-

Theresa MacPhail 2:03:06 Right

Dr. Rangan Chatterjee 2:03:06 ... where we often, um, I'm sure many countries do, where we'll give them and say, "Look, you don't need to sort of cash this prescription in, but if these three things happen-

Theresa MacPhail 2:03:16 Yes

Dr. Rangan Chatterjee 2:03:16 ... or one of them, then it's time to start thinking about it."

Theresa MacPhail 2:03:19 Yeah.

Dr. Rangan Chatterjee 2:03:20 And again, the, the other problem is that we, we live in such a litigation-type culture that then there's a pressure on doctors and healthcare professionals to practice what we call defensive medicine.

Theresa MacPhail 2:03:32 Right.

Dr. Rangan Chatterjee 2:03:32 So they know if they've prescribed it and given that antibiotic, they can't then be sued for negligence. Do you know?

Theresa MacPhail 2:03:41 Yes.

Dr. Rangan Chatterjee 2:03:41 And that's another, that's, we have to, we're, if we're calling this a societal and cultural issue, we have to acknowledge that.

Theresa MacPhail 2:03:46 Absolutely.

Dr. Rangan Chatterjee 2:03:47 So there's a bit on pharmaceuticals. Then I always think about environment, and again, we've covered this, haven't we? Where can you... [smacks lips] I guess I've always had a bias to more natural things, more natural fibers, but we're now seeing [laughs] that more and more, aren't we?

Theresa MacPhail 2:04:02 Yeah.

Dr. Rangan Chatterjee 2:04:02 Like, the more natural your, um, clothes, you know, uh, uh, eczema sufferers will know this, you know?

Theresa MacPhail 2:04:10 Absolutely.

Dr. Rangan Chatterjee 2:04:10 Certain, uh, synthetic, uh, clothes make it much worse and, and inflame their skin, don't they?

Theresa MacPhail 2:04:15 Yeah.

Dr. Rangan Chatterjee 2:04:15 So is there anything you can speak to about, I guess we've talked about chemicals and dishwasher stuff [laughs] and sprays, but I guess you'd just say reduce them as much as we can.

Theresa MacPhail 2:04:24 As much as you can. I mean, of course, you, you can't n- not use them. I mean, we do have to keep things in check. Like, you can't let dust mites run amok or you're gonna develop a dust mite allergy. But maybe just cleaning with less vigor. [laughs] Take it easy on the cleaning, you know? Not-

Dr. Rangan Chatterjee 2:04:44 Just with water sometimes.

Theresa MacPhail 2:04:45 Yes, just with water.

Dr. Rangan Chatterjee 2:04:46 Right?

Theresa MacPhail 2:04:47 Like, you know, look at your... There's no need, I mean, you'll hear this over and over again, there's no need for antimicrobial soap. Just soap denatures most bacteria.

Dr. Rangan Chatterjee 2:04:57 Yeah.

Theresa MacPhail 2:04:57 So you don't need the extra oomph. You don't need to nuke them.

Dr. Rangan Chatterjee 2:05:01 Yeah.

Theresa MacPhail 2:05:01 You know? It's okay to use a lesser level of-

Dr. Rangan Chatterjee 2:05:04 Yeah. A bit, a bit more balance-

Theresa MacPhail 2:05:05 [laughs] Yeah

Dr. Rangan Chatterjee 2:05:05 ... with our environment, right?

Theresa MacPhail 2:05:07 Yeah. And advocate for clean air in your communities. Think about the types of things you're planting. That's another thing I like to tell people. So if you're gardening, like, you know, spend a moment thinking about, "Is this, uh, something that's part of the natural landscape? Am I bringing in, um, a tree that's not usually here?" Because that could cause problems also.

Dr. Rangan Chatterjee 2:05:29 Yeah.

Theresa MacPhail 2:05:29 So just thinking about your little actions that you, or advocating for your community. I know in the US they're trying to, for years they only planted male trees, because female trees are the ones that drop seeds.

Dr. Rangan Chatterjee 2:05:43 Right.

Theresa MacPhail 2:05:43 So they're quite messy in communities, and so we overpopulated cities with male trees that are just pumping out pollen. So now they're trying to think about that.

Dr. Rangan Chatterjee 2:05:53 Yeah.

Theresa MacPhail 2:05:53 And in relationship to this new problem we have.

Dr. Rangan Chatterjee 2:05:56 It's, it's so interesting, all these things that, and again, there's no malice here, I'm sure.

Theresa MacPhail 2:06:00 Right.

Dr. Rangan Chatterjee 2:06:00 It was just a case of-

Theresa MacPhail 2:06:01 I mean, it makes sense, you don't want the mess

Dr. Rangan Chatterjee 2:06:03 ... yeah, exactly, so we can live our nice, humanly and clean lives, right?

Theresa MacPhail 2:06:06 [laughs] Exactly, yes. Yeah.

Dr. Rangan Chatterjee 2:06:07 We don't, we don't want the mess. Yet now we're seeing there's a consequence, and it kinda makes sense these, are we bringing in non-native plants? Um, I think you, you mention in the book about, um, people who work with plants, botanists, and how often they are getting more and more allergies because of the repeated and concentrated exposure. I wonder, is there any research on, um, people who work as cleaners, you know?

Theresa MacPhail 2:06:32 Yes, yeah.

Dr. Rangan Chatterjee 2:06:33 Are they getting more and more allergies? 'Cause they're presumably surrounded by antimicrobials all day, every day.

Theresa MacPhail 2:06:38 Uh, right. Them, um, people at, like hairdressers, because they're constantly around the dyes and the chemicals we use in our hair, nail techs, like, a- anyone who's exposed to substances. Of course, you work in the medical field, people develop latex allergies-

Dr. Rangan Chatterjee 2:06:54 Yeah

Theresa MacPhail 2:06:54 ... because they're constantly putting on latex gloves. So any time we're getting repeated exposures in great dosages.

Dr. Rangan Chatterjee 2:07:02 Yeah.

Theresa MacPhail 2:07:02 So it's, and more and more people, especially this year, are developing respiratory allergies that never had a problem simply because the pollen loads are so great, and the pollen seasons are, most places are extended because of climate change, so it's warmer for longer, and so plants are producing pollen for longer. So a lot of us are starting to get more allergic over time.

Dr. Rangan Chatterjee 2:07:26 You also mention about our modern desire for lush, green, grassy gardens-

Theresa MacPhail 2:07:33 Right

Dr. Rangan Chatterjee 2:07:33 ... and how that may be contributing as well.

Theresa MacPhail 2:07:36 Yeah, I mean, and, and it's, I mean, we haven't talked about meat allergy, the new kid on the block. I don't think it's here yet. You don't have the right tick. But in the US, we have a situation where we have a new allergy called alpha-gal, and it's actually a sugar molecule that's found in red meat. So anything that, uh, you know, deer, um, cow, pig, they all have alpha-gal. And what has been happening is that a tick will feed on a deer, get a little bit of alpha-gal, and then introduce it via a tick bite. You're out hiking, just enjoying your afternoon, a little tick, lone star tick specifically, bites you, and what's interesting about lone star ticks is their saliva produces an allergic reaction. So you'll get itchy with them.

Dr. Rangan Chatterjee 2:08:19 Mm.

Theresa MacPhail 2:08:20 Like, it's almost like a mosquito bite. And they'll deposit a little trace of their last meal. So if they just ate a deer meal and then they attach to you, they deliver just a little bit of that alpha-gal plus the saliva, and it's creating an allergy to alpha-gal. So the next time you have a hamburger ... or a pork chop, you break out in all-over body hives or get m- massively ill.

Dr. Rangan Chatterjee 2:08:44 So we're getting new allergies now-

Theresa MacPhail 2:08:46 Yes

Dr. Rangan Chatterjee 2:08:47 ... developing that we've possibly never had before.

Theresa MacPhail 2:08:49 Yeah, and the connection to the nice lawns is that you know who loves a good lawn? Deer. [laughs]

Dr. Rangan Chatterjee 2:08:55 [laughs]

Theresa MacPhail 2:08:56 They're like salad bars for deer. [laughs]

Dr. Rangan Chatterjee 2:08:59 What, even in, like, suburbia in America?

Theresa MacPhail 2:09:01 Yes, yes.

Dr. Rangan Chatterjee 2:09:02 Deer are coming in.

Theresa MacPhail 2:09:03 Absolutely, yes. They just love a good lawn. [laughs] And unfortunately, what they're tracking in with them are these ticks. And so there's, it's this-

Dr. Rangan Chatterjee 2:09:13 And then they tell their buddies, "Hey, hey, hey

Theresa MacPhail 2:09:14 Right. [laughs]

Dr. Rangan Chatterjee 2:09:14 ... look, there's a great salad bar down this road."

Theresa MacPhail 2:09:17 Yeah. So you're getting this weird situation where there's a tick that is in the neighborhood, plus the deer, and deer are p- proliferating 'cause we don't like to kill them anymore, so they're everywhere. You have this lovely lawn that they absolutely adore, and, and so then you're getting more exposure. Potentially you're just in your backyard sipping on a lemonade, and there are ticks now in your yard because of the deer.

Dr. Rangan Chatterjee 2:09:43 Oh, my. [laughs]

Theresa MacPhail 2:09:43 And so it's, isn't this just the perfect storm of things we're doing?

Dr. Rangan Chatterjee 2:09:49 Is that happening on golf courses as well?

Theresa MacPhail 2:09:51 Yes.

Dr. Rangan Chatterjee 2:09:51 Because golf courses are clearly hyper-artificial environments, lots of them anyway, I think all of them probably, you know, in terms of what is required. Maybe the Scottish links courses are a bit more natural.

Theresa MacPhail 2:10:02 Right, right.

Dr. Rangan Chatterjee 2:10:02 But I don't know, 'cause you presumably need a ton of pesticide and fertilizer to have them the way that they need to be for the game to be played. But I wonder, are we, are we getting reports of deers now-

Theresa MacPhail 2:10:16 [laughs]

Dr. Rangan Chatterjee 2:10:16 ... going to this big 18-hole salad bar-

Theresa MacPhail 2:10:19 Right. [laughs]

Dr. Rangan Chatterjee 2:10:19 ... i, i, in America? Like, d- do you know at all?

Theresa MacPhail 2:10:22 It depends on what type of grass you're planting-

Dr. Rangan Chatterjee 2:10:24 Right

Theresa MacPhail 2:10:24 ... and what bushes you have in your yard, but some of those things are just delectable to deer-

Dr. Rangan Chatterjee 2:10:30 Yeah

Theresa MacPhail 2:10:30 ... and to other mammals. Like, so you know, ticks can attach themselves to small mammals of all kinds, like raccoons. Like, it, they're not picky particularly.

Dr. Rangan Chatterjee 2:10:40 Yeah.

Theresa MacPhail 2:10:40 So any, if you're creating an environment that, um, animals love, then you're accidentally tracking the ticks in, and that's something we never could have predicted though, right? Like, that's a scenario where you're creating a new problem for your body that really has only been around-

Dr. Rangan Chatterjee 2:10:56 Yeah

Theresa MacPhail 2:10:56 ... I think it was discovered in 2010. So this is pretty new stuff.

Dr. Rangan Chatterjee 2:11:01 Yeah. And things we haven't mentioned, and of course, you know, the book is, is such a thorough deep dive, right? It really is. I, I haven't, I don't think I've read one that thorough which goes into allergies and, and the whole history, so I, I appreciate how much work [laughs]

Theresa MacPhail 2:11:14 [laughs]

Dr. Rangan Chatterjee 2:11:14 ... has gone into that. But we've not mentioned even things like air fresheners-

Theresa MacPhail 2:11:18 Yeah

Dr. Rangan Chatterjee 2:11:18 ... deodorant, oven cleaners, um, eyeliner, lipstick, shampoos.

Theresa MacPhail 2:11:24 Yeah.

Dr. Rangan Chatterjee 2:11:24 Right? It is incredible once you start looking at what's in them, and then you start to look at, you know, that list you mentioned from the Environmental Working Group-

Theresa MacPhail 2:11:33 Oh, right, right

Dr. Rangan Chatterjee 2:11:33 ... and how many chemicals are potentially linked to adverse health outcomes or certainly disruptions to the microbiome, right? And again, we've gotta be careful not to scare people, but I hope we've underpinned this conversation [laughs] with empowerment throughout. I've certainly tried my best. I think you have as well.

Theresa MacPhail 2:11:53 I think just knowing that this is the situation and knowing that your body is in these invisible conversations every day not only will help you make better decisions but will help us as a society. Like, I say in the book, and I mean it, there are some hard decisions we're gonna have to make as a group about how we wanna live and how we want our environments to be, and I think those of us who have allergies really understand the importance of making the right decisions, which is, you know, n- doing less and making changes, thinking not just about us and our needs but about the needs of the larger ecosystems around us. And I think that's something that speaks not just to allergies but to the impending climate change crisis. So it's all intermeshed. I mean-

Dr. Rangan Chatterjee 2:12:46 Yeah

Theresa MacPhail 2:12:46 ... this, if you wanna think of allergies as, uh, as partly about a climate crisis, you wouldn't be wrong.

Dr. Rangan Chatterjee 2:12:54 Yeah.

Dr. Rangan Chatterjee 2:12:54 So in terms of treatments, for people who are suffering with allergies at the moment, we've talked a lot about what, what they can do in their, in their lives, but in terms of symptom relief, where are we? What, what's the current state of play with treatments?

Theresa MacPhail 2:13:10 It's been really slow for us to really have any movement or development for many, many years. So treatments have stayed the same for the last 100, 150 years. So it's, the first line of treatment for respiratory is antihistamines, so you can just cope with the symptoms and try to block that histamine response we were talking about. They're fairly effective in mild and moderate cases, but they're not perfect. Um, some of them will do better and make you feel exhausted. There are newer ones that don't dry you out as much, so they're not as effective but they don't make you drowsy, so it's kind of choosing between two options. Um, inhalers, so people will take steroids, um, to control their negative response when they're having an asthma attack, and they will sometimes take a maintenance dose of something to, uh, beta agonist to calm their system down-

Dr. Rangan Chatterjee 2:14:13 Mm

Theresa MacPhail 2:14:13 ... so that they, to prevent the attack in serious asthma cases or moderate asthma cases. So those haven't changed very much.

Dr. Rangan Chatterjee 2:14:20 Right.

Theresa MacPhail 2:14:20 That's been, for a long time it's been the same. And obv- obviously people don't love steroids because, again, it's a sledgehammer. It's just lowering your immune response. Um, it was a big, uh, improvement. They used to take oral steroids for asthma, if you can believe it, and it was terrible. So now with the inhalers, the direct, uh, dose in your lungs has been great for people. So it, it helps to control it, but again, it's not perfect.

Dr. Rangan Chatterjee 2:14:44 Yeah, and you know- As we've already mentioned, that they're not perfect.

Theresa MacPhail 2:14:48 No.

Dr. Rangan Chatterjee 2:14:48 They don't work well for everyone.

Theresa MacPhail 2:14:50 Right.

Dr. Rangan Chatterjee 2:14:50 And of course, there are side effects.

Theresa MacPhail 2:14:53 Yes.

Dr. Rangan Chatterjee 2:14:53 And the longer you're on them for, the greater the potential of those side effects.

Theresa MacPhail 2:14:58 Right.

Dr. Rangan Chatterjee 2:14:58 And I think something that's changed in our profession is, you know, there was always this sort of debate between topical-

Theresa MacPhail 2:15:07 Yes

Dr. Rangan Chatterjee 2:15:07 ... treatments and systemic treatments.

Theresa MacPhail 2:15:09 Right.

Dr. Rangan Chatterjee 2:15:09 Okay, so a topical skin cream is not going to be as harmful from a side effects perspective as taking something through the mouth, which gets everywhere. But I don't think we, it- we can say, you know, I think we're learning more and more that actually things get absorbed from everywhere.

Theresa MacPhail 2:15:28 Right.

Dr. Rangan Chatterjee 2:15:29 And one of the things that I think there is growing awareness of is something called topical steroid withdrawal syndrome-

Theresa MacPhail 2:15:37 Right

Dr. Rangan Chatterjee 2:15:37 ... where people, and you can understand it, they're so itchy, they're in such discomfort, and they've got that steroid there, it's so easy to keep putting it on. Doesn't matter what your doctor says with advice or anything, it's easy, and we're seeing lots of now problems from chronic use. Now, I understand why people are using the creams so much, but it k- speaks to this whole idea that there's, there's no perfect solution here, is there?

Theresa MacPhail 2:16:04 No, especially, I mean, e- eczema for years was the worst one-

Dr. Rangan Chatterjee 2:16:09 Yeah

Theresa MacPhail 2:16:09 ... to treat because it was so hard to get the skin to calm down, and steroids were great except that they thin the skin.

Dr. Rangan Chatterjee 2:16:17 Yeah.

Theresa MacPhail 2:16:17 They can cause, um, secondary infections, so they're not pleasant for the patients to be on. Many patients would tell me they don't wanna take steroids.

Dr. Rangan Chatterjee 2:16:26 Yeah.

Theresa MacPhail 2:16:27 It's just, it's not... And they are afraid of the rebound effect, so once they stop the steroids, sometimes their eczema rash will get worse. And so they're in this continual cycle where they're taking steroids and then getting off them and then having to take them again, and, and la- there have been new drugs, like there's a drug called DUPIXENT, which is a biologic drug, and it's not a sledgehammer. It's working just on one of the mechanisms, and it seems to be a miracle drug, except that it's not. It also causes conjunctivitis. It can increase the amount of eosinophils in your body, which is can sometimes trigger a problem. There's a special food-related allergy called EoE. It's esophageal, but it's involving the eosinophils, so that could potentially lead to a problem. So there are some side effects, but it clears the skin beautifully, so they're s- finding some relief from that, which is nice. But that drug is also about 4,000 US dollars per month-

Dr. Rangan Chatterjee 2:17:29 Right

Theresa MacPhail 2:17:29 ... and you have to take it for life. So it's ju- it really doesn't have an end point-

Dr. Rangan Chatterjee 2:17:34 Yeah

Theresa MacPhail 2:17:34 ... so, uh, that we know of. I mean, it's an early drug, but we think they'll have to be on it continuously. And for food allergy, there is nothing really except for avoidance. There is immunotherapy that's, it is effective in certain cases, but not all cases. So what immunotherapy is, is it introduces a small trace amount of the allergen and allows your body to, over time, slowly, uh, get used to the allergen. So you'll up dose-

Dr. Rangan Chatterjee 2:18:02 Yeah

Theresa MacPhail 2:18:02 ... every week and until you get to the limit where you can maybe have accidentally ingest a peanut and not end up in the ER with-

Dr. Rangan Chatterjee 2:18:11 Yeah

Theresa MacPhail 2:18:11 ... a, a response. And it's typically they do immunotherapy for the more severe allergies for that reason, to give people a little bit of leeway, so that if they accidentally come into contact, it isn't going to be a lethal experience for them. And it does seem to be effective, but again, the maintenance doses have to be maintained. Like, it's not as though we can cure allergies, which I think is really frustrating for a lot of people. As to yet, we don't really have a cure because the cure would involve not triggering the immune system at all. I mean, all we're doing is, is coping with the symptoms-

Dr. Rangan Chatterjee 2:18:48 Yeah

Theresa MacPhail 2:18:48 ... once we have an allergy, but there's nothing that we have that will prevent you from developing one.

Dr. Rangan Chatterjee 2:18:55 And for someone who has, let's say, never had symptoms before, let's say something like hay fever, we're seeing this quite a lot, and they're now starting to get it, and of course, we've discussed some of the reasons why that might be, how pollen rates are increasing. What's the advice now from, from chatting to all these world-leading, uh, allergy specialists, you know, is there anything there like should that person take some antihistamines for symptom relief? Does that increase the chances they're gonna react more in, you know, forthcoming years? Should they not, if possible, just try and avoid it, try and just put up with mild symptoms? I mean, has that advice changed at all?

Theresa MacPhail 2:19:37 Not really. I mean, luckily, the newer antihistamines are pretty mild, so they're, it's not terrible side effects, so they'll s- y- uh, that's why they're available over the counter. Like-

Dr. Rangan Chatterjee 2:19:47 Yeah

Theresa MacPhail 2:19:48 ... the, you can just take them as needed, so you don't have to take them every day. A lot of people will say if, especially if you haven't had allergies before, it's, antihistamine's oral, it's a systemic, so it's basically your whole body is getting a dose of antihistamine, but they're often now recommending that you do something like FLONASE, so you're just trying to impact the systems in your nasal passages themselves, or the allergic, um, eyedrops.

Dr. Rangan Chatterjee 2:20:15 Yeah.

Theresa MacPhail 2:20:16 So you're trying to stop the histamine reactions or tamp down the reactions where you're-

Dr. Rangan Chatterjee 2:20:21 Whereabouts

Theresa MacPhail 2:20:21 ... actually having it, so you don't get the drying effect or whatever else is going on from an oral antihistamine.

Dr. Rangan Chatterjee 2:20:29 Yeah. So basically, newer therapies are on their way.

Theresa MacPhail 2:20:34 Yes.

Dr. Rangan Chatterjee 2:20:34 They're not without side effects.

Theresa MacPhail 2:20:36 Correct.

Dr. Rangan Chatterjee 2:20:36 Um, hopefully this space will continue to evolve. For symptom control, nothing much [laughs] has changed.

Theresa MacPhail 2:20:43 Yeah, and the best, best research going on now is actually in that immune tolerance- ... avenue. So there's a lot of research going on, like can we train or retrain the immune system once a problem develops that goes beyond immunotherapy. So can we somehow speed up immunotherapy and make it better? So almost to reset your immune system, if that makes sense, to make it forget that memory that it, it has stored that oak pollen is bad.

Dr. Rangan Chatterjee 2:21:15 Yeah.

Theresa MacPhail 2:21:15 And so there's some really innovative, uh, research going on, but we're miles away.

Dr. Rangan Chatterjee 2:21:20 Yeah.

Theresa MacPhail 2:21:20 So I've been told we're at least 10 or 20 years away from any of that showing fruit.

Dr. Rangan Chatterjee 2:21:26 Wow. We started off this conversation with some quite worrying statistics about how many of us around the globe are suffering with allergic disease, how many of us will soon be suffering with some form of allergy. So to finish off this conversation, Theresa, are you optimistic about the future or pessimistic?

Theresa MacPhail 2:21:50 Oh, no. Why did you have to ask me that? [laughs]

Dr. Rangan Chatterjee 2:21:54 [laughs]

Theresa MacPhail 2:21:56 Oh, no.

Dr. Rangan Chatterjee 2:21:58 Well, you've got a big smile on your face-

Theresa MacPhail 2:21:59 Oh

Dr. Rangan Chatterjee 2:21:59 ... at the moment, so I don't know what that means.

Theresa MacPhail 2:22:01 Listen, I am just, I'm too steeped in public health. Like, I know that despite knowing what's good for us, do we always make the right decisions? I- and I worry that even if we know exactly what we're doing to ourselves, will we stop doing it? Because it's gonna be inconvenient. It's, it's gonna force us to change things in a way that we'll temporarily we'll need to adjust, and it won't be as convenient or efficient. Uh, it might cost us more money. We don't like to spend money, uh, unless it's on weapons. [laughs]

Dr. Rangan Chatterjee 2:22:44 Yeah.

Theresa MacPhail 2:22:44 You know? We have priorities that don't track with the priorities that I think I've laid out in the book.

Dr. Rangan Chatterjee 2:22:51 Yeah.

Theresa MacPhail 2:22:51 And so I hope, I mean, I guess I'm like, um, Mark Twain's cynic because if you scratch me, there's an idealist underneath that wants to believe that we'll do the right thing, but I worry that I n- we won't.

Dr. Rangan Chatterjee 2:23:09 Well, I think you've written a wonderful book. I think despite all the doom and gloom-

Theresa MacPhail 2:23:13 [laughs]

Dr. Rangan Chatterjee 2:23:13 ... I think it is empowering, and I think knowing this information is crucial if we're gonna make individual and societal change. Thanks for coming to the studio.

Theresa MacPhail 2:23:24 Great. Thank you so much for having me. It was an absolute pleasure. [upbeat music]

Dr. Rangan Chatterjee 2:23:27 If you enjoyed that conversation, I think you are really going to enjoy this one about the negative impact of ultra-processed foods.

Host 2:23:35 A lot of the ailments that we're suffering from are because of what we're eating. You have this exquisite thing called the body. In that body is an incredible healing system