Laxative Abuse Is Associated With a Depleted Gut Microbial Community Structure Among Women and Men With Binge-Eating Disorder or Bulimia Nervosa: The Binge Eating Genetics Initiative.

Objective: This study assessed the associations of binge eating, compensatory behaviors, and dietary restraint with the composition and diversity of the intestinal microbiota among participants with binge-eating disorder or bulimia nervosa.

Methods: We analyzed data from 265 participants aged 18 to 45 years with current binge-eating disorder or bulimia nervosa enrolled in the Binge Eating Genetics Initiative study. We evaluated the associations of binge-eating frequency; presence/absence and frequency of vomiting, laxative use, and compulsive exercise; and dietary restraint with abundances of gut microbial genera, species, and diversity (Shannon diversity, Faith phylogenetic diversity, and Peilou's evenness) from 16S rRNA gene sequencing. General linear regression models adjusted for potential confounders, including age and current body mass index, were used to test associations; p values were corrected for the false discovery rate.

Results: The normalized abundance of four genus- and species-level gut microbes and three diversity indices were lower among Binge Eating Genetics Initiative participants who reported any laxative use compared with those who reported no laxative use. Vomiting frequency was positively associated with the normalized abundance of the genus Escherichia-Shigella , a potential pathobiont, although the association was attenuated to nonsignificance after adjustment for age, body mass index, and binge-eating episodes.

Conclusions: Laxative use was highly and uniformly predictive of a reduced gut microbial diversity including potential commensals and pathobionts, and should be assessed and accounted for in all future studies of eating disorders and the gut microbiota. Future studies should collect data on specific medications-particularly laxatives-and dietary intake to obtain unbiased estimates of the effect of eating disorders on the gut microbiota and identify potential downstream clinical implications.Trial Registration:ClinicalTrials.gov identifier: NCT04162574 .