Gut Bacteria may Help Weight Loss, Microorganisms Found in Mice Lowered Body Fat

Though it might seem gross, a new study reveals that certain microorganisms may be able to help us lose weight, and that includes bacteria.

According to the study, published in the March 27 issue of Science Translational Medicine, data shows that bacteria in the guts of mice changed after they had gastric bypass surgery, a procedure in which surgeons divide a person's stomach and connect the small intestine directly to the smaller walnut-sized portion. When these different microbes were transplanted in sterile mice who did not have the surgery, those animals lost weight quickly.

"Simply by colonizing mice with the altered microbial community, the mice were able to maintain a lower body fat, and lose weight - about 20 percent as much as they would if they underwent surgery," senior author Peter Turnbaugh, a Bauer Fellow at Harvard's Faculty of Arts and Sciences (FAS) Center for Systems Biology, said in a press release.

Researchers performed gastric bypass surgery on a group of obese mice and recorded their weight loss, metabolic performance and gut microbe levels, according to CBS News. Other obese mice who had placebo surgeries and stayed overweight or had placebo surgeries and were then placed on a lower-calorie food diet were also compared to other obese mice.

The mice who had the gastric bypass surgery lost about 30 percent of their body weight in three weeks and had different bacteria in their stools than the other two groups. The mice who had the placebo surgery and didn't go on a weight loss diet regained the weight they initially lost by the end of three weeks. That suggests the surgery, not the weight loss, changed the microbes in the mice.

To further confirm the results, lean, germ-free mice received gut microbes from one of the three groups. Those that got the bacteria from the gastric bypass mice lost weight and fat, while the others did not.

Turnbaugh said that though the numbers seem high, weight loss could have been even greater. Because the mice who received the bacteria weren't on a special diet to increase their weight, there could be an even more drastic weight loss if the mice were eating high-fat or high-calorie food, he said.