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Darwinian

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To answer this question, we must understand hominid evolution. ... Atherosclerosis and Cancer. Atherosclerosis ... 25% of men over 70 have prostate cancer ... – PowerPoint PPT presentation

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Title: Darwinian


1
Darwinian
Medicine
  • An Evolutionary Explanation
  • for Modern Disease

Clint Morehead
2
Darwinian Medicine
  • In 1980, evolutionary biologist Paul Ewald
    proposed an evolutionary approach to the study of
    medicine
  • He suggested that we consider evolution in the
    treatment of infectious diseases

Paul Ewald
3
Darwinian Medicine
  • It has not been until very recently that the use
    of evolutionary theories to treat disease has
    been acknowledged.

Why?
  • Religious Opposition
  • Lack of General Education

4
Darwinian Medicine
Branches
  • Anti-viral and anti-bacterial resistance
  • Real-time evolution
  • Why we even suffer from disease at all
  • Millions of years of hominid evolution

5
Evolutionary Explanation for Disease
Question Why hasnt the Darwinian process of
natural selection eliminated the genes that make
us susceptible to diseases?
6
Evolutionary Explanation for Disease
To answer this question, we must understand
hominid evolution.
7
Evolutionary Explanation for Disease
  • Homo sapiens and their predecessors evolved
    for millions of years as hunter-gatherers
  • 10,000 years ago, they adopted agriculture
  • Mismatch between design and environment

8
Evolutionary Explanation for Disease
Hunter-Gatherers
  • Studies of modern and ancient bands
  • Fished for salmon and other fishes
  • Hunted wild game
  • Gathered fruits and berries
  • Exercised while hunting and searching for
    shelter
  • Provided nearly all essential nutrients and
    protein

9
Evolutionary Explanation for Disease
Shift to Agriculture (a novel environment)
  • Paleopathological studies of Dickson Indian
    mounds show that when they adopted agriculture
  • 50 increase in enamel defects (malnutrition)
  • Risked crop failure/starvation
  • 4X increase in iron deficiency
  • 3X increase in bone lesions (infectuous
    diseases)
  • Life expectancy dropped from 26 to 19 years

10
Evolutionary Explanation for Disease
Atherosclerosis and Cancer
11
Atherosclerosis
  • Second leading preventable killer among
    Americans (behind smoking)
  • MetS obesity, type-II diabetes, high
    cholesterol, high blood pressure

12
Atherosclerosis
Evolutionary Perspective
  • Diet
  • We have evolved to crave sweets and fats (today,
    these products are in abundance)
  • We eat more starches and lack essential
    nutrients
  • Meat comes from livestock rather than game
  • Thrifty genes

13
Atherosclerosis
Evolutionary Perspective
  • Thrifty genes
  • Because food supply was never consistent
  • To regulate intake and utilization of fuel
    sources
  • Efficient storage
  • Today, people who exhibit this phenotype are
    those who become obese

14
Cancer
  • Not a novel disease
  • The genome has defenses against damage (p53
    gene)
  • Has spread for 2 main reasons
  • Our ability to survive long after reproductive
    period
  • Our tendency to interfere with our bodys biology
    (smoking, sunshine, sex, diet, physical
    inactivity)
  • High levels of oxidative stress and accumulation
    of mutations over ones lifetime

15
Cancer
Statistics
  • 80 of all cancers occur at a post-reproductive
    age
  • 25 of men over 70 have prostate cancer
  • Average risk of a 25-30 year-old dying of cancer
    is 50X less than a 65-70 year-old

16
Recap and Conclusion
  • Many modern diseases can be understood better
    from an evolutionary perspective
  • Mismatch between our design and our environment
  • Knowing this could lead to more insightful
    treatments and measures of prevention

17
References
  • American Heart Association. Metabolic Syndrome.
    http//www.americanheart.org/ presenter.jhtml?iden
    tifier4756. A description and statistics
    regarding the metabolic syndrome.
  • Diamond, Jared. The Worst Mistake in the History
    of the Human Race. Discover Magazine. May 1987.
    pp. 64-66.
  • Greaves, Mel. Cancer The Evolutionary Legacy.
    Oxford Oxford University Press, 2000.
  • Haffner S.M., Lehto S., Ronnemaa T., Pyorala K.,
    Laakso M. (1998). Mortality from coronary heart
    disease in subjects with type 2 diabetes and in
    nondiabetic subjects with and without prior
    myocardial infarction. N Engl J Med. 23
    339(4)229-34
  • Kagawa Y, Yanagisawa Y, Hasegawa K, Suzuki H,
    Yasuda K, Kudo H, Abe M, Matsuda S, Ishikawa Y,
    Tsuchiya N, Sato A, Umetsu K, Kagawa Y. (2002)
    Single nucleotide polymorphisms of thrifty genes
    for energy metabolism evolutionary origins and
    prospects for intervention to prevent
    obesity-related diseases. Biochem Biophys Res
    Commun. Jul 12295(2)207-22.
  • Onelife. http//www.onelife.com/evolve/index.html.
    A discussion of human evolution.
  • Nesse, Randolf N. and George C. Williams. Why We
    Get Sick The New Science of Darwinian Medicine.
    New York Vintage, 1994.
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