The Case for Evolutionary Medicine

Nothing in biology makes sense except in the light of evolution
-Theodosius Dobzhansky

We have anthropological data suggesting that both our paleolithic hunter-gatherer ancestors, and many modern day hunter-gatherers suffer low rates of many common diseases including cardiovascular disease, diabetes, obesity, chronic depression, certain cancers, myopia, acne, and many others[4,1,2]. This appears to hold true despite controlling for inheritable traits, and other causes of death: when modern day hunter gatherers adopt a modern lifestyle (especially modern foods) they begin to suffer from these diseases at high rates just as we do.

This is a very powerful observation (an epidemiological correlation). It establishes no cause and effect, but it suggests a whole array of questions (hypotheses):

Is there something different about our modern diet or lifestyle from that of hunter-gatherers, that is contributing to these illnesses?

Could some of the very traits that predispose many of us to illness in modern times actually be beneficial within the environment in which they came about?

If we were to suddenly give up our modern way of life and actually become hunter gathers, it’s likely (but not certain) that we would reduce our chances of getting these modern diseases. Even if this worked, we’d be trading them for a whole host of health problems hunter-gathers have instead such as infant mortality, parasites, and injuries. Still, hunter-gatherers are much healthier and longer lived than most people assume, with a modal life expectancy nearly as long as people in “industrial society,” but less degenerative chronic disease in old age[3].

In short: the hunter-gatherer observation isn’t an argument that you should try to re-enact an ancient lifestyle, but an epidemiological observation that generates a large number of hypotheses about the potential causes of many major diseases. These hypotheses must still be tested with rigorous scientific studies, just like hypotheses generated any other way.

In drug design we have a concept that the therapeutic effect of a drug is sometimes separable from it’s side effects. One part of the molecular structure could be entirely responsible for it’s beneficial effect, while a terrible side effect is coming from an entirely non-essential part.

Lifestyle and dietary factors can be similar to drugs. They’re a set of external stimuli (including numerous pharmacologically active molecules in food) that interact with and alter human physiology in specific ways.

Just like with drug design, are there minor changes we can make to our modern diet and lifestyle to retain the benefits while reducing the side effects?

Evolutionary medicine provides a paradigm to identify and test many factors likely to yield health improvements. Testing these hypotheses will require questioning pre-conceived notions about optimal diet and health since hunter-gatherers don’t seem to live lifestyles consistent with mainstream advice for preventing chronic disease.

Science is the belief in the ignorance of experts
-Richard Feynman

It’s neither possible or desirable to re-create most aspects of a paleolithic hunter-gatherer lifestyle, and that isn’t the goal of evolutionary medicine. Instead the goal is to investigate whether it’s possible to re-create some of the metabolic conditions under which humanity evolved using modern foods and activities whenever it can be demonstrated to be beneficial, safe, and practical in the context of improving health.

Bibliography

1
L Cordain, M R Eades, and M D Eades.
Hyperinsulinemic diseases of civilization: more than just syndrome x.
Comp Biochem Physiol A Mol Integr Physiol, 136
(1): 95-112, Sep 2003.
URL http://www.hubmed.org/display.cgi?uids=14527633.

2
S B Eaton, L Cordain, and S Lindeberg.
Evolutionary health promotion: a consideration of common
counterarguments.
Prev Med, 34 (2): 119-123, Feb 2002.
doi: tex2html_begingrouprm10.1006/pmed.2001.0966.
URL http://www.hubmed.org/display.cgi?uids=11817904.

3
M Gurven and H Kaplan.
Longevity Among Hunter-Gatherers: A Cross-Cultural
Examination
, 2007.
URL
http://www.anth.ucsb.edu/faculty/gurven/papers/GurvenKaplan2007pdr.pdf.

4
S Lindeberg.
The Kitava Study, Accessed May 24th 2011.
URL http://www.staffanlindeberg.com/TheKitavaStudy.html.

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Welcome to Engineering Health!

I’ve added an “About” section which summarizes my current ideas on how to optimize health with easy to make diet and lifestyle changes. In this blog, I intend to summarize and review scientific evidence and explain how I came to form these ideas. I expect that many of my ideas will change as I learn more by writing and researching these articles.

Here are some topics I have planned for upcoming articles:

  • Leptin resistance, and how it relates to obesity
  • The relationship between¬†autoimmune inflammatory disease (including mental illness and metabolic syndrome) and gut barrier health, permeability, and dysbiosis including the latest theories on treating autoimmune disease with diet
  • Helminthic therapy (intentional¬†parasitic worm infection) for treating autoimmune disease
  • LDL receptor regulation, and the relationship between diet and cardiovascular disease
  • How medium-chain triglycerides are metabolized, and the physiology of ketosis
  • The relationship between angiogenesis and cancer
  • The importance of balancing omega-3 and omega-6 fatty acids
  • Widely varying rates of chronic disease between different populations of humans, even after controlling for inheritable traits, and how such observations can lead to novel hypotheses and treatments for common diseases
  • How common logical fallacies and bias can complicate testing and translating evolutionary medicine hypotheses into effective medical advice

Before I post these articles, I need to work out a good citation system so that readers can easily access the underlying scientific literature. I am currently experimenting with LaTeX/BibTeX and the latex2html tool. If you have any other ideas for providing hyperlinked pubmed citations, please reply in the comments.

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