By age 18, most Americans have had up to 20 doses of antibiotics. And that might be making us fat.
According to a commentary published in Thursday's issue of Nature, over-killing bacteria might be causing obesity, diabetes, allergies and asthma.
That's because the human "microbiome" contains good bacteria along with the bad. The theory is that some bacteria protect against disease. One example is Helicobacter pylori. It's linked to ulcers and stomach cancer, so killing it can be a good thing. But scientists have also found that it protects against gastroesophageal reflux, which can lead to esophageal cancer. Absence of H pylori could even affect hormones.
Intriguingly, scientists are also finding that two hormones produced in the stomach – ghrelin and leptin – behave differently when H. pylori isn't around. Ghrelin is the hormone responsible for telling the brain that you're hungry and leptin is supposed to send the signal that you're full.
Martin Blaser, the doctor who wrote the commentary, even thinks doctors might one day need to replace lost "friendly flora" inside our hyper-clean microbiomes. And that's on to of the worrisome antimicrobial resistance that worries medical professionals. So next time you're feeling sniffly, don't be such a wuss. Think twice before you demand your amoxicillin.