Overuse of antibiotics could be involved in a number of conditions

To be filed in the "First Do No Harm" bin, overuse of antibiotics may be implicated not only in obesity, but Irritable Bowel Disease, allergies and asthma. Excerpts follow. Info on my practice here.

In Some Cases, Even Bad Bacteria May Be Good
By KATE MURPHY

THE HYPOTHESIS

Overuse of antibiotics increases the risk of obesity.

THE INVESTIGATOR

Dr. Martin Blaser, New York University Langone Medical Center.


Overuse of antibiotics has led to the creation of drug-resistant bacteria — so-called superbugs, like methicillin-resistant staphylococcus aureus. But now some researchers are exploring an equally unsettling possibility: Antibiotic abuse may also be contributing to the increasing incidence of obesity, as well as allergies, inflammatory bowel disease, asthma and gastroesophageal reflux.

Among those sounding the alarm is Dr. Martin Blaser, a professor of microbiology at New York University Langone Medical Center. In a commentary published in August in the journal Nature, he asserted that antibiotics are permanently altering microbial flora of the human body, also known as the microbiome or microbiota, with serious health consequences...

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His lab has since produced a stream of findings supporting his suspicion. Dr. Blaser and his colleagues discovered, for instance, that the stomach behaves differently after a course of antibiotics eradicates resident H. pylori.

After a meal, levels of ghrelin, a hunger hormone secreted in the stomach, are supposed to fall. But in subjects without H. pylori, the amount of ghrelin in the bloodstream held steady, in essence telling the brain to keep eating.

Moreover, mice in Dr. Blaser’s lab fed antibiotics in dosages similar to those given to children to treat ear and throat infections — which is enough to kill H. pylori in many patients — had marked increases in body fat even though their diets remained the same. (Indeed, farmers have long given antibiotics to livestock to promote weight gain without increasing caloric intake.)

These results dovetail with research by Peter Turnbaugh, a Harvard University geneticist, in collaboration with Dr. Jeffrey Gordon, a gastroenterologist at Washington University in St. Louis. They have found that the ratios of various bacteria in the guts of obese mice and obese humans were significantly different from those of lean controls, suggesting that altering the stomach’s microbial balance with antibiotics might put patients at risk for gaining weight.

Antibiotic overuse may be the root of other health problems, too. An epidemiologist at New York University, Yu Chen, has found an inverse correlation between H. pylori infection and childhood-onset asthma, hay fever and skin allergies in 7,600 participants in the National Health and Nutrition Survey.

Observation research has shown that the elimination of H. pylori actually increases the risk of gastric reflux, which is itself associated with asthma as well as esophageal diseases. Researchers in Switzerland and Germany have reported that mice given H. pylori actually are protected against asthma...

But wider use of antibiotics may be wreaking havoc far beyond that resulting from the loss of H. pylori. “We have so far focused on H. pylori because we have the diagnostic tests to detect it, but you could say H. pylori is an indicator organism for what is probably a vast and disappearing microbiota and increasing disease risk,” said Dr. Blaser...