Exactly how our bacterial companions affect our health is the subject of ongoing research, but one thing is clear: Our decades-long war on germs is looking seriously wrongheaded. In an effort to obliterate disease-causing microbes, we are carpet bombing our microbiota—with the antibiotics we down for a cold (even though the pills are useless against a virus) and the antibiotic-treated meat we eat and the hand-sanitizer dispensers that are everywhere you look. And that war on germs takes a huge toll on beneficial bugs too.
One example: The bacterium Helicobacter pylori causes ulcers and has been linked to stomach cancers. Although it was once in almost everyone’s gut, it is now in just 6 percent of U.S. children, Science magazine reported in 2011, probably due to widespread use of antibiotics and antimicrobials. That should mean fewer ulcers, but there’s a dark lining to that silver cloud: H. pylori may ward off asthma. Scientists led by Martin Blaser, MD, of New York University Langone Medical Center found that those without H. pylori are more likely to have had childhood asthma than those with it. Coincidence? In 2011, Swiss scientists infected half a colony of mice with the bacterium and left the rest germ-free. They showered all the mice with dust mites and other allergens. Mice with H. pylori were fine; those without it had airway inflammation, the hallmark of asthma.
Exactly how H. pylori might ward off asthma is still a mystery, but researchers have made progress in understanding the link between our microbiota and other diseases.
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