Intestinal Energy Harvest Mediates Gut Microbiota-Associated Weight Loss Following Bariatric Surgery.

Abstract

Metabolic and bariatric surgery (MBS) is the most effective treatment for class III obesity. The capacity to efficiently extract intestinal energy is potentially a determinant of varying weight loss outcomes post-MBS. Prior research indicated that intestinal energy harvest is correlated with post-MBS weight loss. Studies have also demonstrated that the gut microbiota is associated with weight loss post-MBS. We aim to investigate whether gut microbiota-associated weight loss is mediated by intestinal energy harvest in patients post-MBS. We examined the relationship between specific gut microbiota, intestinal energy harvest, diet, and weight loss using fecal metagenomic sequence data, bomb calorimetry (fecal energy content as a proxy for calorie absorption), and a validated dietary questionnaire on 67 individuals before and after MBS. Mediation analysis and amachine learning algorithm were conducted. Intestinal energy harvest was a mediator in the relationship between theintestinal microbiota (Bacteroides caccae) and weight loss outcomes in patients post-MBS at 18months (M). The association between the abundance of B. caccae and post-MBS weight loss rate at 18M was partly mediated by 1M intestinal energy harvest (β = 0.001 ± 0.001, P = 0.020). This mediation represents 2.83% of the total effect (β = 0.050 ± 0.047; P = 0.028). Intestinal microbiota and energy harvest improved random forest model's accuracy in predicting weight loss results. Energy harvest partly mediates the relationship between the intestinal microbiota and weight loss outcomes among patients post-MBS. This study elucidates a potential mechanism regarding how intestinal energy absorption facilitates the effect of intestinal microbiota on energy metabolism and weight loss outcomes.