|
How are we
evolving now? Lieberman asks this question in his book, The Story of the
Human Body.
Natural selection and human evolution used to be slow and
steady. It occurred over generations. Over the last few centuries
cultural evolution has caused more pressure on humans than the typical
environmental/natural shifts. We eat differently, are exposed to more and
novel chemicals, we are exposed to different infectious agents, we work
more passively, and so on.
The cultural evolution is changing the environmental
signals that we receive at a light speed pace. It is no longer purely
Darwinian and natural.
These cultural developments are affecting us metabolically
and epigentically, positively and negatively. They are heritable by being
passed on to future generations through the environment. For example,
pesticides and petrochemicals can get into ground water and affect the
drinking water for a whole family over time. We have not evolved genetic
techniques to sufficiently evade such chemical toxicity.
These cultural influences can go both ways. Let us look at
two examples that Dr. Lieberman cites: scurvy and cavities.
Scurvy
is a disorder of dietary vitamin C deficiency that affects our collagen causing
bleeding, neuropathy, fatigue and in extreme cases death. Cavities, tooth
enamel and dentin destruction, are the consequence of bacterial
acid production through the fermentation of food on the teeth.
Culturally,
we have evolved to cure scurvy by fortifying foods with vitamin C and
also make natural vitamin C foods like citrus more available. Good thing
right! Now look at sugar and cavities. Ever since the farming revolution,
humans have consumed increasing quantities of refined foods and sugar
that promote cavity development. We have passed on the
cultural evolutionary knowledge to cure one disease while starting
another.
What we end up with is a mismatch of our genome and the
current environment. This is occurring more and more over the last three
hundred years. As the pace of technological advance takes off
exponentially, the questions of how we can handle them genetically are
growing. Scurvy and cavities are minor issues in comparison to the
emerging science of engineered foods, chemicals in the environment, nanotechnology...., we are starting to see
data emerge that we are losing the battle and developing more
disease.
To be continued.....
Learn from the past,
Dr. M
|
No comments:
Post a Comment