OBJECTIVE: The interplay between the gut microbiome and autonomic nervous system remains unexplored in binge-eating disorder (BED). We aimed to explore specific microbial alterations in BED and examine their potential association with cardiac vagal tone as a distinct bio-behavioral phenotype. METHOD: Women with BED and co-occurring major depressive disorder (BED+MDD; n = 19) were compared to strictly matched controls with MDD alone (n = 38) to isolate BED-specific effects. We analyzed the gut microbiome via 16S rRNA sequencing and assessed cardiac vagal tone using short-term heart rate variability (specifically normalized high-frequency power, HFnu). Nutritional intake was analyzed to explore diet-microbiome interactions. RESULTS: While global diversity did not differ between groups, differential abundance analysis identified lower relative abundance of several fermentative taxa, including Catenibacterium, Acidaminococcus, Pediococcus, Fusobacterium, Megasphaera, and Prevotella in the BED group. Notably, a cross-system association emerged exclusively in the BED group: the depletion of Pediococcus was strongly correlated with reduced vagal tone (HFnu; p = 0.003) and specific micronutrient patterns. This relationship was absent in the MDD-only controls. DISCUSSION: Our findings demonstrate a BED-specific link between the depletion of the fermentative guild, autonomic instability, and dietary energy intake. This linked state may reflect a physiological response to the acute substrate surges characteristic of binge-eating, potentially compromising gut-brain axis homeostasis. Future research incorporating direct measures of binge behavior and luminal environment is required to validate whether these microbial patterns represent a causal mechanism or a reproducible physiological marker of the disorder.
Liang et al. (2026) studied this question.