The guts of obese people are teeming with a distinctive mix of bacteria that seems to make them prone to gaining weight, a startling discovery that could lead to new ways to fight the obesity epidemic, researchers are reporting today.
Obese people have more gut microbes that are especially efficient at extracting calories from food, the researchers said, and the proportion of these super-digesting organisms ebbs as they lose weight.
Moreover, when the scientists transplanted gut bugs from obese mice into lean mice, the thin animals started getting fat, providing more support for the provocative theory that the bacteria that populate the gut play an important role in regulating weight.
“There appears to be a link between obesity and the type of bugs in your gut,” said Jeffrey Gordon of Washington University School of Medicine in St. Louis, who led the series of experiments being published in today’s issue of the journal Nature. “The difference in the structure of microbial ecology of our gut may set us up for susceptibility to obesity.”
Gordon and his colleagues stressed that more work is needed to explore the findings. And they cautioned against trying to manipulate “gut flora” with antibiotics or microbe-containing “probiotic” pills sold in health food stores.
But if the findings are confirmed and better understood, they could lead to profound new insights into one of the world’s biggest health problems, they said.
“In the future, we could potentially manipulate the structure and function of these microbial societies as a new approach toward preventing and treating obesity,” Gordon said.
The findings produced enthusiasm and caution from other researchers. Some praised the work for possibly offering a long-sought alternative explanation for the obesity epidemic. Perhaps some change, such as a food additive or antibiotic use, has caused a fundamental shift in gut flora, making it easier for many people to gain weight.
Others suspect that if gut microbes do play a role, it’s probably relatively minor.
“This is extremely interesting,” said Hans-Rudolf Berthoud of the Pennington Biomedical Research Center in Baton Rouge, La. “But lifestyle and the environment are still the major factors in the obesity epidemic.”
On a broader level, the findings highlight the symbiotic relationship humans maintain with the trillions of microorganisms that populate our bodies, Gordon and others said.
Scientists have long known that the human body is crawling with germs, primarily bacteria, which cover the skin and inhabit every orifice.
By some estimates only one out of every 10 cells in the human body is actually human. These organisms perform a host of functions, especially in the gut, where they help digest food.
