New Bacteria Found After Weight-loss Surgery Could Keep Obesity Away

Roux-en-Y gastric bypass is one of the most drastic weight-loss surgeries in regards to rapid initial weight-loss. The logic behind gastric bypass is simple: rearrange the digestive tract so the stomach holds less and the food ‘bypasses’ part of the small intestine, allowing fewer calories to be absorbed. 

For many obese patients, especially ones with type 2 diabetes, gastric bypass has been the most successful surgery in regards to significant weight-loss and curing co-morbidities. Severely obese patients can lose up to 75 percent of their excess weight and live the rest of their lives diabetes free. However, the diabetes remission often occurs before the significant weight-loss. This has weight-loss experts and surgeons thinking that Roux-en-Y not only changes the anatomy but also metabolism or the endocrine system.

Studies published in March 2013 conclude that Roux-en-Y gastric bypass not only helps weight-loss by re-routing the digestive tract but also by changing the bacteria in the gut. The microscopic organisms, microbiota, in the gut are different in lean and obese people. But the mix of microbes changes after an obese patient undergoes gastric bypass and becomes more like the microbiota in lean people. Researchers did not know whether this microbial change, change caused by or involving microscopic organisms, was the cause or the effect of post-bypass weight-loss.

A new study conducted by researchers at Massachusetts General Hospital and Harvard University set out to find that answer. They did this by performing various surgeries on mice and testing whether it’s the Roux-en-Y gastric bypass surgery, surgery in general, or the microbiota that causes weight-loss. First they performed Roux-en-Y on obese mice. As expected they slimmed quickly losing 29 percent of their weight. Next they performed “fake” Roux-en-Y on other obese mice. The researchers made incisions as if they were going to do a gastric bypass, but instead connected everything up as usual. Lastly, the researchers transferred the gut microbiota from the Roux-en-Y mice to microbe-free obese mice. Results: the recipient mice lost weight and fat with undergoing surgery. However, obese mice that received gut microbes from mice that had “sham” Roux-en-Y did not slim down.

This was the first experimental evidence that proves changes in the gut microbiota cause the weight-loss after gastric bypass, and that the new post-bypass mix of microbes can cause weight-loss in animals that have not undergone surgery.

“The effects of gastric bypass are not just anatomical, as we thought.” Said 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.”

This new discovery could open doors to the future of weight-loss surgery. Until then, this new “slimming bacteria” could be added to the benefits list for gastric bypass.

FirstHealth’s Bariatric Center offers Roux-en-Y gastric bypass as well as the adjustable gastric band and gastric sleeve procedures. You can learn about the benefits of each procedures by attending a free weight-loss surgery information session on the first Thursday or third Monday of every month. For more information call (800) 213-3284.

FirstHealth Moore Regional Hospital offers weight-loss treatments and support to patients in the Pinehurst, Raeford, Sanford, Lumberton, Laurinburg, Rockingham, and Troy regions of North Carolina and beyond.