Do soft drinks disrupt gut bacteria enough to impact mental health?

Study details: A multicenter cohort study in Germany analyzed 932 adults (405 with major depressive disorder [MDD], 527 healthy controls) to assess the relationship between soft drink consumption, MDD diagnosis/severity, and gut microbiome composition. Multivariable regression and mediation analyses were performed, focusing on the abundance of Eggerthella and Hungatella.

Results: Soft drink consumption was significantly associated with both MDD diagnosis (odds ratio, 1.081; 95% confidence interval, 1.008-1.159) and symptom severity, with stronger effects in women. In female participants, higher soft drink intake correlated with increased Eggerthella abundance, which significantly mediated the association between soft drink consumption and both MDD diagnosis and severity (explaining 3.8%–5.0% of the effect). No significant mediation was observed for Hungatella.

Clinical impact: These findings support a mechanistic link between dietary sugar, gut microbiome alterations, and depression, particularly in women. Results highlight the importance of dietary assessment and counseling in depression management and suggest that interventions targeting the gut microbiome may be a promising adjunctive strategy. Public health measures to reduce soft drink consumption could help mitigate depression risk at the population level, especially among vulnerable groups.

Source:

Edwin Thanarajah S, et al. (2025, September 24). JAMA Psychiatry. Soft Drink Consumption and Depression Mediated by Gut Microbiome Alterations. https://pubmed.ncbi.nlm.nih.gov/40991280/