Short-term study suggests vegan diet can boost gut microbes related to body weight, body composition and blood sugar control -- ScienceDailyThe study included 147 participants (86% women and 14% men; mean age was 55.6±11.3 years), who were randomised to follow a low-fat vegan diet (n=73) or to make no changes to their diet (n=74) for 16 weeks. At baseline and 16 weeks, gut microbiota composition was assessed, using uBiome kits. Dual energy X-ray absorptiometry was used to measure body composition. A standard method called the PREDIM index was used to assess insulin sensitivity. Following the 16-week study, body weight was reduced significantly in the vegan group (treatment effect average -5.8 kg), particularly due to a reduction in fat mass (average -3.9 kg) and in visceral fat. Insulin sensitivity also increased significantly in the vegan group. The relative abundance of Faecalibacterium prausnitzii increased in the vegan group (treatment effect +4.8%). Relative changes in Faecalibacterium prausnitzii were associated with decreases in body weight, fat mass and visceral fat. The relative abundance of Bacteoides fragilis also increased in the vegan group (treatment effect +19.5%). Relative changes in Bacteroides fragilis were associated with decreases in body weight, fat mass and visceral fat, and increases in insulin sensitivity.