Evolutionary medicine

Evolutionary medicine or Darwinian medicine is the application of modern evolutionary theory to understanding health and disease. Modern medical research and practice has focused on the molecular and physiological mechanisms underlying health and disease, while evolutionary medicine focuses on the question of why evolution has shaped these mechanisms in ways that may leave us susceptible to disease. The evolutionary approach has driven important advances in our understanding of cancer,autoimmune disease, and anatomy. Medical schools have been slower to integrate evolutionary approaches because of limitations on what can be added to existing medical curricula.

Adaptation works within constraints, makes compromises and tradeoffs, and occurs in the context of different forms of competition.

Adaptations can only occur if they are evolvable. Some adaptations which would prevent ill health are therefore not possible.

Other constraints occur as the byproduct of adaptive innovations.

One constraint upon selection is that different adaptations can conflict, which requires a compromise between them to ensure an optimal cost-benefit tradeoff.

Different forms of competition exist and these can shape the processes of genetic change.

Humans evolved to live as simple hunter-gatherers in small tribal bands, a very different way of life and environment compared to that faced by contemporary humans. This change makes present humans vulnerable to a number of health problems, termed "diseases of civilization" and "diseases of affluence". Humans evolved to live off of the land, and take advantage of the resources that were readily available to them. They evolved for the stone-age, and the environments of today bring about many disease causing ailments, that may or may not be deadly. "Modern environments may cause many diseases-for example, deficiency syndromes such as scurvy and rickets" (Williams, 1991)

In contrast to the diet of early hunter-gatherers, the modern Western diet often contains high quantities of fat, salt, and simple carbohydrates, which include refined sugars and flours. These create health problems.

Examples of aging-associated diseases are atherosclerosis and cardiovascular disease, cancer, arthritis, cataracts, osteoporosis, type 2 diabetes, hypertension and Alzheimer's disease. The incidence of all of these diseases increases rapidly with aging (increases exponentially with age, in the case of cancer).

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