#270 ‒ Journal club with Andrew Huberman: metformin as a geroprotective drug, the power of belief, and how to read scientific papers
Peter Attia, MD, and Andrew Huberman, Professor of Neurobiology at Stanford, host a journal club discussing a metformin study and how beliefs influence drug effects. They also share their methodologies for interpreting scientific papers.
Deep Dive Analysis
14 Topic Outline
Introduction to Journal Club and Paper Interpretation
Metformin: History, Mechanism, and Use in Type 2 Diabetes
Defining Insulin Resistance and its Causes
Metformin's Geroprotective Potential: The 2014 Bannister Study
Critique of Bannister Study: The Role of Informative Censoring
The 2022 Keys et al. Study Reassessing Metformin's Survival Advantage
Interpreting Epidemiological Data: Crude Mortality and Hazard Ratios
Limitations of Epidemiology and Personal Experience with Metformin
Current Thoughts on Metformin for Longevity and Caloric Restriction
Peter and Andrew's Process for Reading Scientific Papers
Understanding Belief Effects vs. Placebo Effects
Neurobiology of Nicotine and its Cognitive Enhancement
The Perl et al. Study: Belief's Impact on Nicotine's Brain Effects
Implications of Belief-Dependent Drug Responses in Medicine
9 Key Concepts
Metformin Mechanism
Metformin inhibits complex one of the mitochondria, which changes the ratio of adenosine monophosphate to adenosine diphosphate. This action reduces the amount of glucose the liver puts out, helping to lower blood glucose levels in diabetics.
Insulin Resistance
This occurs when cells, primarily muscle cells, become less responsive to insulin, requiring more insulin to transport glucose into the cell. It is often caused by intramuscular fat accumulation, inactivity, sleep deprivation, and hypercortisolemia.
Geroprotection
This term refers to drugs or interventions that target the fundamental biological hallmarks of aging, such as decreased autophagy, increased senescence, or genomic instability, with the aim of protecting against or delaying the aging process itself, rather than specific age-related diseases.
Informative Censoring
A methodological limitation in some studies where participants who deviate from the initial inclusion criteria (e.g., stopping a drug, progressing to a more severe condition) are excluded from the final analysis. This can bias results by only considering a subset of the original group.
Hazard Ratio
A statistical measure used in survival analysis to compare the risk of an event (like death) between two groups over time. A hazard ratio greater than 1 indicates an increased risk in the exposed group, while less than 1 indicates a reduced risk.
Statistical Power
The probability that a study will find a statistically significant difference between groups if a real difference truly exists. It is crucial for interpreting negative results, as a study might fail to find significance if it is underpowered to detect the actual effect size.
Kaplan-Meier Curve
A graphical representation of survival probability over time, commonly used in medical research to estimate the fraction of patients living for a certain amount of time after treatment or diagnosis. The curve always decreases monotonically, showing cumulative survival.
Belief Effects
These are physiological and psychological changes in response to a treatment that are influenced by an individual's knowledge, expectations, and beliefs about that treatment. Unlike binary placebo effects, belief effects can scale with the amount and type of information received, impacting biological responses.
Nicotinic Receptors
These are a type of acetylcholine receptor found in the brain, particularly in areas like the thalamus and basal forebrain. When activated, they increase the signal-to-noise ratio of sensory information, leading to enhanced focus and clarity.
10 Questions Answered
Metformin is a generic drug used for type 2 diabetes that inhibits complex one of the mitochondria, which reduces the liver's glucose output and helps lower blood sugar.
Insulin resistance is when cells require more insulin to take up glucose, often caused by intramuscular fat accumulation, physical inactivity, sleep deprivation, and high cortisol levels.
The Bannister study found that type 2 diabetics on metformin had a 15% relative reduction in all-cause mortality over 2.8 years compared to matched non-diabetic controls, suggesting a potential geroprotective effect.
The Keys et al. study, using a larger Danish registry and a more rigorous analysis including discordant twins and different censoring methods, found that diabetics on metformin still had a significantly higher mortality risk compared to non-diabetic controls, contradicting Bannister's finding of a survival advantage.
Epidemiological studies, despite large sample sizes, cannot fully control for all confounding variables and inherent biases, making it hard to isolate the effect of a single intervention without randomized assignment.
No, Peter Attia stopped taking metformin five years ago, partly due to concerns about the Bannister study's methodology and its observed impact on his resting lactate levels and exercise performance.
Peter Attia believes there is no clear evidence that short-term caloric restriction or fasting offers a direct longevity benefit to humans, especially considering potential muscle mass loss and the lack of reliable aging biomarkers.
Placebo effects are binary (drug vs. no drug), while belief effects involve the scaling of physiological and psychological responses based on the amount and type of information an individual believes about a treatment, even if the actual dose is constant.
Nicotine, by binding to nicotinic acetylcholine receptors in areas like the thalamus and basal forebrain, increases the signal-to-noise ratio of sensory information, enhancing focus and clarity.
The study suggests that what patients are told and believe about a drug's dose and effects can significantly alter their brain's physiological response, potentially influencing treatment outcomes and even how side effects are experienced.
29 Actionable Insights
1. Leverage Belief Effects
Recognize that your beliefs about drug doses and effects can biologically impact your physiology and brain activation, not just subjectively.
2. Deep Self-Analysis
Engage in intensive analysis, potentially with a skilled professional, to explore your subconscious and catalyze transformative life decisions and experiences.
3. Exercise for Insulin Sensitivity
Prioritize regular exercise as it is one of the most important actions to ward off insulin resistance and maintain metabolic health.
4. Sleep for Insulin Sensitivity
Ensure adequate sleep, as sleep deprivation can profoundly reduce glucose disposal and induce insulin resistance.
5. Prevent Excess Fat Accumulation
Avoid accumulating excess fat, especially its spillover into muscles, liver, and pancreas, as this exacerbates insulin resistance.
6. Maintain Glucose Homeostasis Through Lifestyle
Achieve glucose homeostasis and energy balance through good sleep hygiene, consistent exercise, and thoughtful eating, without necessarily relying on caloric deficit.
7. Reframe Stress Positively
Reframe your perception of stress by believing it enhances performance, which can lead to improved outcomes compared to viewing it as limiting.
8. Reframe Drug Side Effects
View drug side effects as evidence that the medication is working, which can make the experience less negative and potentially increase perceived relief from primary symptoms.
9. Dosage Belief Alters Response
Understand that your belief about a drug’s dose can significantly alter your brain’s physiological response, influencing how your body reacts.
10. Influence Satiety Through Belief
Recognize that your belief about a food’s caloric content and nutritional value can influence physiological responses like ghrelin suppression and satiety.
11. Believe in Exercise Benefits
Actively acknowledge and believe in the health benefits of your daily physical activity, as this belief alone can lead to greater positive physiological outcomes like weight loss.
12. Avoid Nocebo Effect
Be cautious about dwelling on potential negative side effects of a drug, as this can trigger the nocebo effect, leading to the subjective experience of those side effects.
13. Structured Paper Reading
When reading scientific papers, identify the questions, understand the approach, note the findings, and critically assess if conclusions are substantiated by the data.
14. Research Scientific Methods
When encountering unfamiliar scientific methods in a paper, look up their purpose online to significantly aid comprehension.
15. Prioritize Figures in Papers
After reading the title and abstract, first review the figures to digest visual information before delving into the main text for deeper understanding.
16. Adapt Paper Reading Strategy
Adjust your paper reading approach based on familiarity; for new topics, use figures to generate questions, then read methods for clarity.
17. Review Supplemental Paper Info
Always check the supplemental information of scientific papers, as crucial data or analyses are often placed there due to journal length constraints.
18. Start a Journal Club
Engage in or resume a formal journal club (e.g., monthly) to review scientific papers, as it’s a great way to learn and develop interpretation skills.
19. Interpret Scientific Papers
Develop the skill of reading and interpreting scientific papers to understand research findings and think like scientists and clinicians.
20. Don’t Rely Solely on Abstracts
Avoid relying solely on a paper’s abstract for full understanding, as it’s usually insufficient to grasp the complete findings and implications.
21. Titrate Drug Dosages
When starting a new medication, titrate the dose up gradually rather than starting at a full dose to avoid severe side effects.
22. Manage Cortisol Levels
Be aware that hypercortisolemia (high cortisol) can contribute to insulin resistance, implying a need to manage stress or other factors that elevate cortisol.
23. Re-evaluate Metformin for Longevity
Consider that metformin has not shown success in the ITP for geroprotection, suggesting re-evaluation of its use solely for anti-aging purposes in insulin-sensitive individuals.
24. Monitor Resting Lactate
If taking a weak mitochondrial inhibitor, monitor resting fasted lactate levels (aim for 0.3-0.6 millimole) as elevated levels may indicate increased shunting of glucose to lactate.
25. Metformin & Muscle Growth
Be aware that metformin may attenuate hypertrophy and strength gains, which could be a factor for individuals prioritizing muscle mass and exercise performance.
26. Explore SGLT2 Inhibitors
Consider SGLT2 inhibitors as a potential drug for glucose disposal, based on mechanistic studies, ITP results, and human trials showing benefits even in non-diabetics.
27. Eat Unprocessed Foods
Focus on consuming most nutrients from unprocessed or minimally processed food sources, as this approach can enhance satiety and allow for greater food intake.
28. Acknowledge Longevity Biomarker Gaps
Understand that current longevity interventions lack reliable biomarkers to indicate whether they are effectively moving one in the right direction or at the correct dosage.
29. Gradual Nicotine Reduction
When attempting to quit nicotine, consider progressively reducing the actual dose while maintaining the belief that the dose is consistent to mitigate reward pathway disruption.
5 Key Quotes
The difference between being metabolically healthy and having profound type 2 diabetes is one teaspoon of glucose in your bloodstream.
Peter Attia
If a 95% confidence interval does not cross the number zero, it's statistically significant.
Peter Attia
What we believe about the effects of a drug, presumably, in addition to what we believe about how much we're taking and what those effects ought to be, clearly are impacting at least the way that our brain reacts to, to those drugs.
Andrew Huberman
Your brain is a prediction making machine. It's a data interpretation machine, but it's clear that one of the more important pieces of data are your beliefs about how these things impact you.
Andrew Huberman
Anal seepage, only a physician... could find it, a, um, an appropriate term to describe.
Andrew Huberman
1 Protocols
Process for Reading Scientific Papers
Andrew Huberman- Identify the general and specific questions the paper is asking.
- Understand the approach and methods used to test those questions, looking up unfamiliar terms.
- Determine what the researchers found, often by reading figure headers first.
- Go back at the end and ask whether the major conclusions drawn in the paper are truly substantiated by what was found and what was done.