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Tom Dayspring is a world-renowned lipidologist and one of the most thoughtful teachers in the field of lipid metabolism. In this episode, Tom returns to The Drive for a deep dive into the relationship between lipids and brain health, beginning with the fundamentals of cholesterol transport before exploring why the brain's cholesterol system operates almost entirely independently from the rest of the body. Tom examines the roles of apoB, apoA-I, and especially apoE in cholesterol homeostasis, discusses how APOE genotype influences Alzheimer's disease risk, and unpacks the complex links between cholesterol metabolism, amyloid, and tau pathology. He also reviews what is currently known—and still uncertain—about the effects of statins, ezetimibe, omega-3 fatty acids, and emerging CETP inhibitors on brain health and neurodegenerative disease risk. Although highly technical, this conversation provides an essential framework for understanding the nuanced relationship between lipid-lowering therapies, cardiovascular disease prevention, and neurodegenerative diseases in an area often clouded by misinformation.

We discuss:

• The fundamentals of cholesterol transport in the body, and how peripheral cholesterol metabolism differs from cholesterol handling in the brain [2:45];
• How cholesterol is transported through plasma and stored within cells, and why lowering LDL cholesterol does not deplete the body or brain of cholesterol [11:45];
• How apoB particles drive atherosclerosis, why lowering lipids matters, and the factors that influence individual cardiovascular risk [20:00];
• How the brain produces and transports its own cholesterol using apoE lipoproteins independently of circulating cholesterol and apoB-containing lipoproteins [29:00];
• How apoB structure influences LDL receptor binding and LDL clearance [39:00];
• How neurons acquire cholesterol from apoE-containing lipoproteins and why desmosterol serves as a unique marker of cholesterol synthesis in the brain [41:45];
• The difference between the APOE gene and the apoE protein, the major APOE genotypes found in humans, and how APOE4 influences Alzheimer's disease risk [48:45];
• HDL function beyond cholesterol: immune function, protein cargo, and communication with the brain [53:30];
• How APOE4-associated defects in brain cholesterol transport may promote Alzheimer's disease: amyloid production, neuronal cholesterol homeostasis, and cholesterol clearance [58:00];
• Statins and brain health: reviewing the evidence of the potential impact of statins on cognition and Alzheimer's disease risk [1:09:00];
• Desmosterol and 24S-hydroxycholesterol as biomarkers of brain cholesterol metabolism and statin effects [1:17:15];
• Possible cognitive benefits of ezetimibe beyond lowering apoB [1:19:30];
• EPA, DHA, and the evidence for omega-3 fatty acids in brain health [1:23:15];
• Obicetrapib: an emerging CETP inhibitor with potential implications for both cardiovascular and brain health [1:31:00]; and
• More.

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In this episode, Peter dives into the pharmacology of sleep, exploring where sleep medications fit within the broader framework of achieving healthy, restorative sleep. He explains why sleep is a biological imperative, why behavioral and environmental interventions must remain the foundation of good sleep, and how medications can serve as useful tools when carefully matched to a person's specific sleep problem. Peter examines the major classes of prescription sleep medications, including how they work, their effects on sleep architecture, their duration of action, side effects, and risks of tolerance and dependence. He also discusses the dangers of using sleep drugs without a clear understanding of the underlying problem being treated, the role of medications as short-term bridges during periods of acute stress, pain, or anxiety, and the promise that newer drugs like DORAs may hold for Alzheimer's prevention in high-risk individuals. Finally, Peter reviews the evidence for select off-label medications and supplements commonly used for sleep.

We discuss:

• The biological foundations of sleep, the major drivers of sleep dysfunction, and the role sleep medications can play when appropriately matched to specific sleep problems [1:00];
• Sleep hygiene, circadian alignment, and the medical causes of insomnia: building the foundation for effective sleep treatment [7:15];
• Understanding insomnia: hyperarousal, CBT-I, paradoxical insomnia, and why different sleep problems require different treatments [12:45];
• The difference between sedation and physiologic sleep: sleep architecture, restorative sleep stages, and matching medications to specific sleep problems [17:00];
• Benzodiazepines for insomnia: mechanisms, effects on sleep architecture, and the risks of long-term use [18:45];
• Z-drugs for insomnia: how Ambien, Sonata, and Lunesta work, and the ongoing risks of sleep medications targeting GABA systems [23:00];
• Dual orexin receptor antagonists (DORAs) and the future of sleep medicine: orexin signaling, sleep architecture, and the emerging connection between sleep and Alzheimer's disease [27:15];
• Melatonin for circadian timing: how timing signals differ from sedatives in the treatment of sleep disorders [36:30];
• Trazodone for insomnia: preserving deep sleep while minimizing the risks of traditional sedative-hypnotics [42:00];
• First-generation antihistamines for sleep: short-term sedation, anticholinergic risks, and concerns about long-term cognitive health [44:00];
• Sleep supplements and the evidence behind them: glycine, magnesium, ashwagandha, phosphatidylserine, and more [45:45];
• Takeaways: supplement quality, individualized sleep treatment, and the importance of matching interventions to the biology of insomnia [52:00]; and
• More.

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In this "Ask Me Anything" (AMA) episode, Peter explores how to think critically about medications and supplements by focusing not on whether an intervention is inherently "good" or "bad," but on whether it makes sense for a specific person with a specific problem. He explains why clearly defining the problem matters more than choosing the intervention itself, how the intended purpose of a medication or supplement should influence the standard of evidence required, and why mechanistic reasoning alone is rarely enough to justify taking something. Peter also examines how baseline risk shapes the true benefit of an intervention, why relative risk statistics can be misleading without proper context, and how to weigh not only side effects, but also cost, inconvenience, and opportunity cost when deciding whether something is worth taking. Additionally, he discusses practical ways to evaluate whether a supplement is actually having a meaningful effect, how to think about discontinuing therapies, why supplements deserve far more skepticism than they often receive, and the small group of over-the-counter supplements he believes may offer a reasonable risk-reward trade-off.

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We discuss:

• How to properly define health problems before considering medications or supplements [1:45];
• How the intended purpose of an intervention should determine evidence standards and risk tolerance [5:00];
• Understanding the hierarchy of evidence for medications and supplements and avoiding the mistake of treating weak evidence as clinical proof [9:00];
• Why mechanistic explanations can be misleading when evaluating longevity interventions [13:15];
• How baseline risk—and the distinction between relative and absolute risk reduction—changes the real-world benefit of medications and supplements [18:15];
• Thinking beyond side effects: the many forms of downside associated with medications and supplements [22:45];
• Why medications and supplements require different standards of trust and evidence [26:00];
• How to structure meaningful self-experiments with medications and supplements to determine if it's they're working [30:30];
• How to monitor the effects of medications and supplements without fooling yourself [32:30];
• How to periodically reevaluate and potentially discontinue medications and supplements [35:15];
• The biggest risks and failure modes of over-the-counter supplements: efficacy, poor quality control, contamination, interactions, toxicity, and marketing-driven overuse [38:30];
• Why the US supplement regulatory system creates unreliable products [41:45];
• A practical framework for evaluating medications and supplements [46:30];
• Over-the-counter supplements with the best balance of evidence and low downside risk [48:00]; and
• More.

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