Intestinal bacteria may be responsible for at least part of the fat-shedding effects of a popular weight-loss surgery, a new study in mice suggests. Those naturally occurring bacteria not only trim the tummies of mice that have had the surgery but, when transplanted into mice that have not had surgery, cause them to lose weight as well.
Roux-en-Y, the most common technique for gastric bypass, diverts food around most of the stomach and upper small intestine. Some patients go on to lose large amounts of weight, and the surgery may produce other health benefits, such as improving symptoms of type 2 diabetes (SN: 9/10/11, p. 26). In mice, those benefits stem from a bacterial blend fostered by bypass surgery, researchers report March 27 in Science Translational Medicine.
The finding could be a first step toward “bypassing the bypass” as a means of treating obesity and diabetes, says coauthor Lee Kaplan, a gastroenterologist who heads Massachusetts General Hospital’s Weight Center. Possible treatments may include replacing or augmenting an obese person’s intestinal community.
Still, says Guilherme Campos, a surgeon at the University of Wisconsin School of Medicine and Public Health in Madison, the study was done in mice, so the role that gut microbes play in humans’ weight loss is unknown. “Is it the main driver? Likely not, but it is still likely one of the components that assist gastric bypass patients to lose weight in the long run.”