Thyroid health: interpreting symptoms, diagnosing & treating dysfunction (AMA 89 sneak peek)

1. 0:00 – 0:11

   Intro

   1. PAPeter Attia0:00

      [upbeat music] Hey, everyone. Welcome to "The Drive Podcast." I'm your host, Peter Attia.

   2. SPSpeaker0:04

      [upbeat music]

2. 0:11 – 7:43

   Why thyroid management is unusually complex and what the thyroid does

   1. SPSpeaker0:11

      Peter, welcome to another AMA. How are you doing?

   2. PAPeter Attia0:14

      Very good, thanks.

   3. SPSpeaker0:15

      Good. Well, today we're gonna talk about the thyroid. So this is something that it seems like people hear about all the time but really don't understand well. And so I think what might be helpful for people before we get into it is maybe just explaining why this is such a complex, complicated topic.

   4. PAPeter Attia0:31

      Yeah, I don't-- I mean, I think there's probably several ways to think about that. Uh, but certainly one reason is that the regulation of thyroid hormones is quite complicated. Um, and that's true for several reasons, but I'll state one at the outset, which is it's a hormone system for which the Goldilocks principle applies, right? Too much is a problem, and too little is a problem. Now, conversely, if you think about testosterone, you know, male androgens, that's not the case, right? Um, there's really no naturally occurring scenario where you have too much of it. And by the way, even when people are having testosterone replaced, if you give them too much, they generally just feel better. Um, so it's not... You know, it, it's actually a, a more asymmetric, um, problem. But the thyroid is, is particularly nuanced. Um, and there's a feedback system in the brain that works a lot like other hormones we, we know about, uh, including testosterone. But again, um, a second thing that then makes this really complicated is that you have an inactive hormone that is the thing that's actually gets, getting secreted by the thyroid gland that gets converted to an active hormone locally. Um, and by the way, there are different ways that it gets converted, so there are different enzymes that convert it, and, uh, it's... So, so, so I think that's, that... We're-- Obviously, I-- we're gonna talk about all of these things. Um, I guess the other thing I would say is how you interpret the lab test is a little bit problematic. Um, again, when you are looking at something like, uh, estrogen, progesterone, or testosterone, provided you're using the right assay, like an LC-MS, um, test, you're-- you can very accurately measure those hormones. Um, as we'll discuss in the thyroid, that's not always the case. Um, I would say another thing that makes this complicated is the importance of how symptoms fit into the diagnosis. Now, again, that should be part and parcel with every endocrine diagnosis. It's just that the symptoms of, you know, low estrogen and progesterone and testosterone are much more, uh, apparent and have fewer overlaps with other potential diagnoses than, than we see with, with, uh, with thyroid. So I think when you take all of these things together, it's, it's, um... Managing the thyroid hormone is sort of, uh, a ripe environment for ideologic battles and pseudoscience and sort of, uh, a little bit of chicanery, um, when it comes to sometimes practitioners doing more harm than good when they're trying to te- treat patients.

   5. SPSpeaker3:15

      Given that, it seems like the best place to probably start is just explaining to people what is the thyroid, and what does it actually do?

   6. PAPeter Attia3:22

      So it's a small gland with two lobes on either side of your throat, really sitting on top of your voice box. Uh, just below the Adam's apple is really where it, it, it starts, and then it rises to the side, uh, and then goes down the other side. So it makes, uh, a hormone, but primarily the one that it makes is called T4, and it's called T4 because it has four iodines on it. And, um, the downstream of that effect is that the-- this hormone regulates the metabolic rate of basically every cell in the body. So you can think of the thyroid, uh, gland as the gain knob on your body's metabolic amplifier. Um, so it's not really deciding what your cells do so much as how loudly they do it. Um, so if you have too little signal, and everything is basically gonna run cold and slow. Your heart rate's gonna drop. Your weight's gonna probably creep up. Uh, you feel like you're operating at half capacity. You're low in energy, et cetera. Uh, too much of it, of course, and again, it's not a big line between too much and too little, and everything goes up. Everything's hot and fast. So your heart rate goes up. You might even have unexpected weight loss, anxiety, insomnia, uh, atrial fibrillation, all sorts of things like that. Um, I'd say kind of roughly, like, five percent, um, of adults in the United States have some clinically meaningful thyroid dysfunction. Um, so for that reason, I mean, it's wildly prevalent, and that means, by definition, many people listening to us right now, um, are, are experiencing that. Um, but as I've kind of alluded to, I think it's one of the more commonly mismanaged conditions I see, um, and that's obviously why I want to spend a lot of time on it. We do see a lot of patients come into our practice, um, who are being mismanaged in this regard, and I think by extension, many other doctors are probably seeing that too.

   7. SPSpeaker5:15

      Yeah, and so with that mismanagement, it's almost like there's a lot of disagreement around this, right? It's not a super clean topic, not a super clean biology in a way. And so why do you think that this can be such a contentious topic for doctors and people to understand?

   8. PAPeter Attia5:31

      I think because the system is complex, um, which is not unique to the body. Um, but when you combine that with the fact that we don't have visibility into its moving parts, I think that creates a bit of a perfect storm. So as I kind of alluded to, the gland mostly secretes an inactive prohormone, T4. Um, and then there's a decision about how much of that hormone becomes the active hormone, T3, but that decision is happening locally, tissue by tissue. Um, now TSH, thyroid-stimulating hormone, is a great marker of whether the gland is being told to work harder, um, but it's a step removed from what's actually happening inside the liver, the heart, the brain. [lip smacks] Then there's also kind of a real philosophical split. So there's a camp of p- physicians, I suppose, that think hypothyroidism is underdiagnosed, undertreated, um, and then, you know, that's kind of the when you're a hammer, everything is a nail camp, right? Like any problem that anybody shows up with, if you're depressed, if you're having GI issues, if you're, you know, having sleep pro- like whatever the problem is, it's hypothyroidism. Um, [lip smacks] at the other end of the spectrum, you have a camp of, you know, other folks who say, "No, no, no, this is completely overdiagnosed, uh, by this kind of everybody has hypothyroidism school of thought." And basically, we're only going to treat hypothyroidism if it is so overt that a medical school student after one hour of an endocrinology class would be able to make this diagnosis blindfolded. Um, as you can probably imagine, I think both of these schools are incorrect, um, and that there's a messy middle ground where the truth probably lies. And the goal of this podcast, of course, is then to kinda walk people through the physiology carefully enough, um, [lip smacks] that you can see both the grains of truth on each side of those, uh, schools of thought, but perhaps more importantly, what they might be missing and therefore where we can hopefully land on, uh, a place to, to treat people.

3. 7:43 – 15:32

   Why symptoms are insufficient for diagnosis and the risks of underdiagnosis and overtreatment

   1. SPSpeaker7:43

      Yeah. And so on that, it seems like for a lot of people, the first time they start thinking about the thyroid is they're either tired, gaining weight, something just, quote-unquote, "doesn't feel right." You do what anyone does and they go to Google, they search it, and there's a ton of people, a ton of things saying, "Hey, there's something wrong with the thyroid. They're hypothyroid." And so how much can you actually tell from some of those like generic symptoms like that?

   2. PAPeter Attia8:10

      Yeah. Unfortunately, almost nothing about, uh, you know, fatigue and feeling off is specific to any one organ system or cause. Um, and we see this in formal blinded studies trying to diagnose hypothyroidism purely off of symptom clusters without any biochemistry. So they essentially couldn't distinguish hypothyroid from euthyroid, meaning patients have normal levels of thyroid. [lip smacks] Um, the same complaints show up with sleep deprivation, iron deficiency anemia, perimenopause, and menopause-related symptoms. Um, and the last one, by the way, may be one of the single biggest confounders in my practice, especially since the timing often overlaps, but that's maybe a later issue. Um, but what's going on inside the endocrine system and how to fix it are actually kinda different, so you do need the rigor of multiple data sources. Um, and, and I think that a lab-first approach, uh, rather than a symptom-first approach is more likely to get you in the high zone of probability, um, [lip smacks] again, based on how nonspecific these symptoms are.

   3. SPSpeaker9:19

      So I think it's a good place to then kinda look at it clinically in your practice, right? So where are you seeing doctors potentially missing a real thyroid problem, and where do you see people on the other end going too far in that other direction?

   4. PAPeter Attia9:33

      Well, look, I think a lot of medical care misses real disease when it treats a lab value in isolation from the patient. So dismissing somebody with a patchy gland, positive antibodies, and a family history because their TSH is, you know, quote-unquote "normal" at 4.2. Um, and that's-- so that's a legit failure. Um, but just as often, I'm seeing the overreach in the other direction, and this is most visibly in this strand of, uh, what people call functional medicine that treats subclinical hypothyroidism as close to basically a ubiquitous finding. Um, so if you go looking, you'll find practitioners who insist that the standard TSH ranges are too permissive and treat a borderline free T3 or elevated reverse T3 as irrefutable proof of tissue-level hypothyroidism regardless of TSH, um, or regardless of free T4, uh, and sometimes regardless of symptoms. So having decided that a patient has a thyroid problem, they will build an elaborate root cause narrative, gut health, adrenal fatigue, toxic burden, et cetera, around kind of a lab picture that, in a large share of cases, is actually within a normal variation or will normalize on its own. So rather than just kind of accepting that a person doesn't have hypothyroidism when their blood work comes back normal by conventional standards, they will maybe, um, use this kind of functional medicine framework to, um, basically assume that there's a problem at the level of the conversion of T4 to T3 in the tissue. Ask the question, "What's driving the conversion impairment?" Um, [lip smacks] I think in reality, a large share of patients with mildly elevated TSH will normalize spontaneously, um, on repeat testing. And I think overtreatment with standard thyroid hormone is, is not benign. It can actually cause cognitive symptoms, atrial fibrillation, which we've seen countless times, bone loss, and more. Um, so I think both failure modes are real, and some patients go, you know, from their family doctor and, you know, get hit at one end of it and then are driven into the clinic of a quack who hits them with the other end. And, um, again, uh, just to reiterate, I think both extremes are, are, are likely doing more harm than good. Thank you for viewing this sneak peek of an Ask Me Anything episode of The Drive. As a premium member, you'll get immediate access to the full AMA episode you just watched a sneak peek for, our entire back catalog of AMA episodes, and all future AMA episodes. You'll get longevity-focused premium articles packed with actionable insights. You'll get unrivaled show notes for each and every episode of The Drive and much more. Become a premium member today at peterattiamd.com/subscribe. 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Episode duration: 15:36