Altering Gut Bacteria Could Rival Bypass Surgery Effects

Obese patients hoping to slim down with bariatric surgery may soon be able to get the weight-loss effects of gastric bypass without going under the knife, according to a new study.

While bariatric surgery helps people drop pounds by rerouting the digestive tract so the stomach holds less food, a new study by researchers at Harvard University and Massachusetts General Hospital shows that changes in the bacteria found in the gut may have more of an impact on weight loss.

According to the study, conducted on mice using the specific Roux-en-Y method of gastric bypass, the surgery almost immediately transforms bacteria into microbes most often found in slender people.

Those bacteria tend to not only boost metabolism, but also extract fewer calories from foods during the digestive process. 

The findings echo clues previously observed in patients with type 2 diabetes who underwent gastric bypass. Healthcare workers noted that those patients’ diabetic symptoms often went into remission even before the surgery led to significant weight loss.

The results suggest that gastric bypass can perhaps be mimicked through the introduction of these so-called slimming microbes, inducing weight loss without any actual surgical intervention.

That’s likely to be good news for obesity experts, since gastric bypass is a risky surgery, especially since it is performed on people already at a high risk for surgical complications.

To test the theory, researchers performed gastric bypass on a group of obese lab mice, then transferred gut microbes from those mice after surgery to a control group of equally obese mice. They performed faux surgeries on another group to ensure that the surgical process itself was not responsible for the weight loss.

Both the gastric bypass group and the microbe group lost weight, but the mice who underwent faux gastric bypass did not.

“The effects of gastric bypass are not just anatomical, as we thought,” says Dr. Lee Kaplan, senior author of the study and associate professor of medicine at Harvard Medical School. “They’re also physiological. Now we need to learn more about how the microbiota exert their effects.”

 The study appeared in a recent issue of the journal Science Transitional Medicine.