#67 - AMA #8: DNA tests, longevity genes, metformin, fasting markers, salt, inflammation, and more

Aug 19, 2019 Episode Page ↗
Overview

In this AMA, Peter Attia and Bob Kaplan discuss the utility of DNA kits for various diseases, longevity genes, inflammatory markers, advanced cardiac measurements, metformin for longevity, salt's role in health, and surprising markers from quarterly fasts.

At a Glance
14 Insights
18m 2s Duration
7 Topics
4 Concepts

Deep Dive Analysis

Utility of DNA Kits for Health Information

Distinguishing Somatic and Germline Mutations

Genetic Testing for Cancer Susceptibility

Genetic Testing for Cardiovascular Disease Risk

Genetic Testing for Diabetes Risk

APOE Status and Alzheimer's Disease Risk

Genetic Guidance for Nutrition and Exercise

Germline Mutations

These are genes inherited from one's parents, present in the base cell DNA. Some germline mutations, like BRCA or Lynch syndrome, can dramatically increase the risk of certain cancers, but they are relatively rare and often identifiable through family history.

Somatic Mutations

These are mutations acquired after an individual has received all their genetic material, meaning they are not inherited. Over 95% of cancers are driven by somatic mutations, which are not detectable by standard germline genetic tests like 23andMe.

Liquid Biopsies

This is an emerging technology that involves blood tests designed to find rare cancer cells or DNA fragments with acquired mutations. It aims to detect somatic mutations that are like a 'needle in a haystack' in the bloodstream.

Phenotype vs. Genotype in Health Assessment

Genotype refers to an individual's genetic makeup, while phenotype refers to observable characteristics or measurable traits. For many conditions like cardiovascular disease and diabetes, Peter Atiyah emphasizes that deep phenotypic assessment (e.g., measuring LP(a) levels, insulin response, or using a CGM) provides more actionable and insightful information than genetic predispositions alone.

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Are DNA kits useful for providing actionable health information?

For most common diseases like cancer, cardiovascular disease, and diabetes, current DNA kits (e.g., 23andMe) offer very little actionable information because most relevant mutations are acquired (somatic) or phenotypic markers are more insightful.

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What is the difference between germline and somatic mutations?

Germline mutations are inherited genes that increase disease risk, while somatic mutations are acquired after birth and are responsible for the majority of cancers, not typically found in standard genetic tests.

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Does genetic testing help predict cancer risk?

For the vast majority (over 95%) of cancers, which are driven by somatic mutations, current genetic tests are not useful. Highly penetrant germline mutations (like BRCA, Lynch syndrome) are rare and often known through family history.

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Is genetic testing useful for cardiovascular disease or diabetes?

Not significantly. For CVD, important markers like LP(a) can be measured directly. For diabetes, phenotypic markers like hyperinsulinemia and continuous glucose monitoring (CGM) data are far more actionable and insightful than genetic predispositions.

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Is APOE status useful for Alzheimer's disease?

Yes, knowing APOE status can be empowering and provide extra motivation for prevention. It might also influence decisions regarding contact sports for children due to a potential increase in susceptibility to head trauma.

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Can genetic tests guide nutrition and exercise?

Currently, Peter Atiyah is not convinced that existing genetic tests provide much actionable value for tailoring diet or exercise, as empirical determination of what works for an individual is often more effective and necessary.

1. Prioritize Phenotypic Health Data

Focus on deep phenotypic measurements (e.g., hyperinsulinemia, glucose disposal, CGM data) rather than genetic predispositions for conditions like diabetes and heart disease, as these provide more actionable and trackable insights for reversal.

2. Use Continuous Glucose Monitor

Wear a Continuous Glucose Monitor (CGM) for months to understand your glycemic response, as this offers orders of magnitude more insightful and actionable information than genetic tests for diabetes risk.

3. All-Hands-On-Deck for Dementia

Regardless of your APOE status (even with lower risk genes), adopt an ‘all-hands-on-deck’ approach to prevent dementia, as everyone with a brain is at risk of Alzheimer’s disease.

4. Measure LP(a) Directly

Instead of relying on genetic tests for LP(a) risk, directly measure your LP(a) levels, as it’s easier and provides the same important information for cardiovascular disease assessment.

5. Empirically Test Diet & Exercise

Empirically test different diets and exercise routines to determine what works best for you, rather than relying solely on genetic predispositions, as the empirical step is always necessary.

6. Monitor Insulin Resistance Markers

Monitor subtle markers of insulin resistance, such as ferritin elevation and patterns of glucose disposal, as these provide more valuable insights than genetic predispositions for diabetes.

7. APOE4 & Kids’ Contact Sports

If your child has the APOE4 gene, consider guiding them towards non-contact sports like tennis instead of contact sports like soccer, due to a potentially increased susceptibility to head trauma.

8. Use APOE4 for Motivation

If you have the APOE4 gene, use this knowledge as extra motivation to work harder on dementia prevention strategies.

9. Genetic Testing for Adopted

If you are adopted and lack family medical history, genetic testing for highly penetrant germline mutations (e.g., BRCA, Lynch syndrome) might be more beneficial to uncover unknown risks.

10. Calibrate Genetic Test Expectations

Calibrate your expectations for the overall yield and usefulness of current genetic tests, especially for cancer, cardiovascular disease, and tailoring nutrition/exercise, as their value is often low.

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If you have a brain, you're at risk of Alzheimer's disease.

Richard Isaacson (quoted by Peter Atiyah)

I'm not sure how you could trust me if I'm telling you about something when you know I'm being paid by the company that makes it to tell you about it.

Peter Atiyah

I'm just not over the moon excited about using sort of the current crop of genetic tests.

Peter Atiyah
20,000 to 30,000
Nominal number of genes in the human genome The number is subject to revision, with some estimates closer to 30,000.
North of 95%
Percentage of cancers that are NOT germline mutations This means most cancers are due to somatic mutations acquired after birth.
8% to 12%
Percentage of population with the LPA gene This gene is associated with LP(a) levels, which can be measured phenotypically.
25%
Percentage of population with APOE4 positive gene This includes individuals with one or two copies of APOE4.
Two-thirds
Proportion of Alzheimer's disease cases made up by APOE4 positive individuals Despite making up 25% of the population, APOE4 positive individuals account for a significant majority of cases.
One-third
Proportion of Alzheimer's disease cases made up by individuals without APOE4 Even without the APOE4 gene, 75% of the population still accounts for a third of Alzheimer's cases, emphasizing that having a brain puts everyone at risk.