New Data Help Explain Weight Loss After Gastric Bypass

Harvard University researchers said yesterday that gastric bypass surgery leads to weight loss not simply due to decreased caloric intake or absorption, but likely also due to alteration of the gut flora as a result of the surgery. Reporting online yesterday in Science Translational Medicine, the group said studies in humans and rats have already shown that the Roux-en-Y gastric bypass (RYGB) procedure restructures the gut microbiota, prompting the hypothesis that some of the effects of RYGB are caused by altered host-microbial interactions. The researchers used a mouse model of RYGB to demonstrate that transfer of the gut microbiota from RYGB-treated mice to nonoperated, germ-free mice resulted in weight loss and decreased fat mass, potentially due to altered microbial production of short-chain fatty acids. The researchers said they hope that finding ways to manipulate microbial populations to mimic those effects could become a valuable new tool to address obesity. 

A study by researchers at the University of Pittsburgh led to cautions, however, on the use of RYGB surgery in some patients, finding that it can also lead to alcohol use disorder. Read about that study in Psychiatric News here. 

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