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Peter Attia MD#21 – Tom Dayspring, M.D., FACP, FNLA – Part II of V: Lipid metrics and cholesterol regulation
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At a glance
WHAT IT’S REALLY ABOUT
Dayspring Explains Lipoproteins, Cholesterol Metrics, Sterols, and How Cholesterol Is Regulated
- Dayspring argues lipids travel through plasma only inside lipoproteins, and atherosclerosis reflects apoB-containing particles delivering sterols to the arterial wall.
- The episode traces how lipid measurement evolved from Gofman's ultracentrifuge to total cholesterol, the Friedewald LDL-C calculation, direct assays, and NMR particle counting.
- Dayspring says apoB and LDL particle number track risk better than LDL cholesterol, so discordance between them can only be spotted by measuring both.
- The speakers cover sterol chemistry and intestinal absorption, describing how NPC1L1, ABCG5/G8, ACAT and ABCA1 let cholesterol in while working to keep phytosterols out.
- They discuss cholesterol synthesis and its pathways, the brain's separate cholesterol system, and why plasma cholesterol says little about cellular cholesterol or flux.
IDEAS WORTH REMEMBERING
5 ideasLipids need lipoproteins to travel in plasma
Dayspring says plasma is water and lipids are hydrophobic, so they go nowhere unless carried in a lipoprotein; he likens atherosclerosis to illegal dumping of sterols in the artery wall.
ApoB is the one protein that stays on the particle
Other apoproteins can transfer between particles, but apoB stays on chylomicrons, VLDL, IDL and LDL. It acts as the ligand for receptor uptake, and each particle carries one, so apoB serves as a particle count.
Cholesterol metrics are poor-man's proxies for particle number
Dayspring says total cholesterol, LDL-C and non-HDL-C are easily assayed stand-ins, with non-HDL-C correlating with apoB better than LDL-C, which beats total cholesterol.
Discordance means risk follows the particle metric
Dayspring says some people have high apoB or LDL-P with good LDL-C, or the reverse, and in virtually every trial risk follows the particle metric, so both should be measured.
The Friedewald estimate falters as triglycerides rise
It assumes VLDL cholesterol is triglycerides divided by five, but Dayspring says it becomes erroneous somewhere between triglycerides of 150 and 200, and direct LDL-C is better at higher levels.
WORDS WORTH SAVING
5 quotesif you learn nothing else today, learn the, the first thing is lipids, for the most part, go nowhere in the human body unless they're a passenger inside a lipoprotein.
— Dr. Tom Dayspring
atherosclerosis is just the evidence of illegal dumping, where a lipoprotein, instead of bringing lipids to wherever it's supposed to be bringing it, was bringing sterols to the arterial wall.
— Dr. Tom Dayspring
if you ever go to a doctor and you're told, "I'm very happy 'cause your LDL cholesterol is normal," say, "Well, so am I, doc, but by the way, what was the ApoB or LDL particle count?"
— Dr. Tom Dayspring
It is not possible to discuss lipids without that.
— Dr. Peter Attia
Cholesterol cannot be metabolized and produce ATP in the process.
— Dr. Tom Dayspring
High quality AI-generated summary created from speaker-labeled transcript.
