The term
"microbiome" refers to the millions of bacteria, viruses, and fungi
that live in and on our bodies. Until recently, scientists focused mainly on
how these organisms cause disease and how they can be destroyed. For example,
the bacterium Helicobacter pylori, which is
linked to certain diseases of the stomach, has been nearly eliminated by
antibiotics in developed countries. Martin Blaser, a microbiologist at New York
University, says this approach should be questioned. He notes that, from an
evolutionary standpoint, H. pylori's
long association with humans makes no sense if its only function is to harm us.
Indeed, recent findings
suggest H. pylori also has a positive role.
Studies of mice show that eliminating H. pylori from
the stomach causes hormonal changes that lead to severe weight gain. In nations
where antibiotics have reduced the presence of H. pylori,
obesity may therefore be one consequence. Further studies indicate that humans
without H. pylori are more likely to develop
diseases such as asthma, which has become widespread throughout developed
countries.
Dr. David Relman, a professor
at the Stanford University School of Medicine, is convinced that the medical
establishment's focus on killing germs needs to change. The increasing number
of allergies in developed countries, he says, is related to the destruction of
the microbiome by antibiotics. Relman compares the microbiome to a complex
forest ecosystem. He says we should manage it the way we manage wilderness
preserves: with the understanding that diversity is key to the overall health
of the system.
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