Source: “The Ultimate Social Network,” Jennifer Ackerman,
Scientific American, June 2012, pages 36-43.
Even after taking
a shower, there are trillions of one-cell organisms on and in your body, over
six pounds for a typical adult. And it is a good thing.
Bacterial cells
outnumber human cells ten to one. Over the past ten years scientists have begun
to understand where they come from and what they do. The human DNA has between
twenty and twenty-five thousand genes.
Microbes have over three million. This allows many variations. Some of
these include genes that encode for beneficial compounds that the body cannot
produce. Other bacteria train the body not to overreact to outside threats. And
some microbes bring disease, decay and death.
In the womb the
fetus is fairly sterile of bacteria, encountering the first while passive
through the birth canal. The environment provides the rest, and no two people
end up with the same cluster of bacteria (commensals, from the Latin for “sharing
a table”, also called our microbiome). Even identical twins have differing
commensals.
The inadvertent overuse
of antibiotics and sterilization may destroy beneficial microbes. “Our
individual fates, health and perhaps even our actions may have much more to do
with the variation in the genes found in our microbiome than in our own genes.”
Even beneficial microbes can cause us harm if they end up in the wrong place,
in the blood for example.
Much more study,
now in progress, will determine tests for the presence or absence of important
microbes in various parts of the body, and what remedies will alter the
microbome to help the patient cope with many health problems. “Teasing apart
cause and effect can be difficult.”
It seems that the
idea of a sterile environment is one to avoid. Everything in moderation, even
cleanliness.
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