Evolution may explain disease

A different way of viewing illness is spreading through the
medical community in the form of the study of Darwinian
medicine.

Darwinian medicine acknowledges the concept of evolution by
natural selection as an invaluable key to understanding the causes
of many diseases, and also suggests various ways to prevent
them.

Analyzing evolutionary trends allows us to understand why we are
where we are in terms of health and lifestyle and encourages us to
surmise what health problems we might be able to prevent in the
future. It involves a hunt for evolutionary explanations of
susceptibilities to disease, which leads us to compare the
environment our ancestors experienced to our environment today.

The “mismatch” between our bodies and our
environment is essentially what fosters the numerous diseases that
today’s society encounters, including obesity and heart
disease. By means of natural selection, the gene pool was shaped to
offer maximum efficiency for past environments, which were far
different from those in which we currently live.

Since natural selection works slowly, most of our genome has
remained suitable for the circumstances of our ancestors and not
for modern Western conditions. Lifestyle changes in human
populations account for many health problems in our technological
society.

Hunter-gatherers consumed mostly high-fiber and low-fat foods,
and their nutrition was accompanied by much physical exertion.
Nowadays, many people are overindulgent, eating high-fat and
high-sugar foods and leading sedentary lifestyles with little
physical activity.

In addition, our bodies are good at converting food into fat and
then storing it. During times when calories were few and food was
scarce, this was advantageous for survival.

Today’s society deals with the ramifications of such
environmental and behavioral differences in the form of diseases
such as obesity, high blood pressure and diabetes. Such maladies
were uncommon among foragers, suggesting that many chronic
disorders are avoidable and developed as a result of the differing
circumstances between then and now.

There are also certain adaptations that appear to no longer be
advantageous, but principles of Darwinian medicine recognize them
as essential to sustain. One of the body’s defenses, a fever,
is often misinterpreted as a symptom of disease. In actuality, it
is an evolutionary adaptation the body instigates to create an
uninviting atmosphere for microbes and ultimately to overcome
infection.

Darwinian medicine does not seek to automatically suppress
symptoms such as fever, coughing and diarrhea without considering
their purposes as the body’s defenses against toxins and even
worse ailments.

Moreover, related disease-causing genes that remain apparent in
populations are actually selected for in the long run, not
against.

Utilizing an evolutionary framework is helpful because it allows
us to designate certain means of prevention for common diseases.
The key method enforced in Darwinian medicine is distinguishing
between diseases and defenses.

Darwinian medicine argues that modern medicine seems to work
against instead of with the body in its constant attempts to thwart
common natural defensive systems like coughing. Darwinian medicine
suggests that defensive systems not be suppressed by medications
such as painkillers and anti-inflammatory drugs ““ which may
further aggravate the course of the illness ““ but instead
believes in being respectful of the body’s restorative
processes.

Darwinian medicine has already offered us many explanations as
to why we get sick and has even attempted to explain the current
worldwide epidemics of cardiovascular disease and breast cancer.
There is a good chance that this relatively new method of
approaching medicine will offer us simple solutions to some of
life’s most troubling questions.

Ahdout is a first-year medical student at the UCLA David
Geffen School of Medicine.