Image from the Paliy Lab, Wright State University
A newly published article in Nature tells us exactly what we’d expect about the bacteria that live in our guts and what we eat — one influences the other.
But the study of microbial rRNA in Americans, Venezuelan Amerindians, and Malawians also reports interesting things. New things. Such as this: Americans have a mere 75 percent of the bacteria species living inside our South American and southern African counterparts.
The Nature study doesn’t explain why, but its authors suggest a few possible culprits, including the overuse of anti-bacterial products in American homes and the overuse of antibiotics in American meats.
The vast majority of antibiotics used in the U.S. — perhaps as much as 80 percent — are not used to treat bacterial infections in humans. They’re used in agriculture, primarily added to feed for animals that will be slaughtered.
These are animals that may or may not be sick. Ranchers don’t care. Long ago, agricultural scientists reported that the prophylactic use of antibiotics increased yield, and a bad idea was born.
A flurry of studies in the U.S., Asia, and Europe over the last 15 years support a causal relationship between antibiotic overuse in agriculture and antibiotic resistance in human-dwelling bacteria, including that boogeyman of superbugs, methicillin-resistant Staphylococcus aureus, or MRSA. (Staph would be the bacterium that causes wound infections, but its primary hangout is your nose, and it would like to thank you for spreading it… constantly.)
Last month, the U.S. Food and Drug Administration announced new rules that now require veterinarians to issue a prescription for antibiotics before they can be used for farm or ranch animals.
I suppose the authors of the Nature paper ought to revisit this subject in two or three years, to see if American guts have been repopulated.