Changes in Gut Microbiome after Bariatric Surgery Versus Medical Weight Loss in a Pilot Randomized Trial

Background Gut microbiota likely impact obesity and metabolic diseases. We evaluated the changes in gut microbiota after surgical versus medical weight loss in adults with diabetes and obesity. Methods We performed 16S rRNA amplicon sequencing to identify the gut microbial composition at baseline and at 10% weight loss in adults with diabetes who were randomized to medical weight loss (MWL, n = 4), adjustable gastric banding (AGB, n = 4), or Roux-en-Y gastric bypass (RYGB, n = 4). Results All participants were female, 75% reported black race with mean age of 51 years. At similar weight loss amount and glycemic improvement, the RYGB group had the most number of bacterial species (10 increased, 1 decreased) that significantly changed ( p