Summary: New research indicates that sugary soft drinks may harm mental health as well as physical health, especially in women. The study links high soft drink consumption to a greater likelihood of major depressive disorder (MDD) and to more severe depressive symptoms, potentially through changes in the gut microbiome.
The association appears to be connected with an increased abundance of the bacterium Eggerthella, previously associated with depression. These results point to the possibility that dietary interventions and microbiome-targeted approaches could help prevent or treat depressive disorders.
Key facts
- Gender-specific risk: Women who consume sugary soft drinks showed about a 17% higher risk of depression in this study.
- Microbiome link: The gut bacterium Eggerthella was more abundant in women with high soft drink intake.
- Therapeutic potential: Nutrition changes and probiotic or microbiome-directed therapies may reduce depressive symptoms.
Source: DZD
A multicenter study coordinated with the German Center for Diabetes Research (DZD) strengthens evidence that frequent consumption of sugary soft drinks affects not only metabolism but also mental health, with pronounced effects in women—likely mediated by changes in the intestinal microbiome.
Regular intake of sugary beverages is already known to raise the risk of obesity, type 2 diabetes, cardiovascular disease and certain cancers. Growing evidence now suggests these drinks may also influence mental health. Until now, however, the link between soft drink consumption and diagnosed major depressive disorder (MDD), and the biological pathways involved, were not clearly established.
Soft drink consumption associated with higher risk of depression
To explore this relationship, researchers analyzed cross-sectional data from the Marburg–Münster Affective Cohort (MACS). The sample included 932 adults aged 18 to 65 recruited from the general population and primary care between 2014 and 2018. Of these, 405 were patients diagnosed with MDD and 527 were healthy controls.
The analysis revealed that greater soft drink consumption was associated with both the presence of an MDD diagnosis and increased symptom severity. The effect was especially strong among women: high intake corresponded to an approximately 17% higher probability of depression (odds ratio 1.167) and to worse symptom severity.
Microbiome changes as a likely mechanism
The study also examined gut microbiota composition to identify possible biological mechanisms. In women who frequently consumed sugary soft drinks, researchers found a significantly higher abundance of bacteria from the Eggerthella genus. Previous research has linked Eggerthella to depressive disorders, and the current findings suggest this microbe may partially mediate the relationship between soft drink intake and depression.
“Our data indicate the link between soft drinks and depressive symptoms may be conveyed through alterations of the gut microbiome,” said study leader Dr. Sharmili Edwin Thanarajah of University Hospital Frankfurt and the MPI for Metabolism Research Cologne, a partner of the DZD.
Sugary beverages such as cola and lemonade provide glucose and fructose and often include additives, preservatives, and artificial sweeteners. These components can disturb the gut’s microbial balance, favoring inflammation-promoting bacteria while reducing beneficial short-chain fatty acid production. Animal studies indicate that such microbiome shifts can trigger inflammatory responses in the nervous system and increase depressive-like behavior.
Notably, the observed association was sex-specific. In men who consumed soft drinks regularly, the study found neither an increase in Eggerthella nor a clear link to depressive symptoms. The reasons for this sex difference remain uncertain; hormonal differences and sex-specific immune responses are possible contributors.
Is the microbiome a treatment target?
DZD researcher Rachel Lippert from the German Institute of Human Nutrition Potsdam–Rehbrücke (DIfE) noted that these results could expand prevention and treatment options for depression. Microbiome-based interventions—such as targeted dietary changes, prebiotics, probiotics, or other strategies to rebalance gut bacteria—may help alleviate depressive symptoms in some individuals.
The authors recommend integrating the influence of nutrition on mental health into public education, clinical care concepts, and prevention programs. Because diet can alter the microbiome, small changes in consumption patterns—particularly reductions in soft drink intake—could have meaningful population-level benefits given how common these beverages are.
About this depression and microbiome research news
Author: Birgit Niesing
Source: DZD
Contact: Birgit Niesing – DZD
Image: The image is credited to Neuroscience News
Original Research: Closed access.
Article title: “The bitter taste of sweet drinks: Increased consumption of soft drinks is linked to depression via gut microbiota alterations” by Sharmili Edwin Thanarajah et al., JAMA Psychiatry
Abstract (summary)
Importance
Soft drink consumption is associated with negative physical and mental health outcomes, but the link to major depressive disorder (MDD) and the underlying mechanisms have been unclear.
Objective
To investigate whether soft drink consumption is associated with MDD diagnosis and symptom severity, and whether gut microbiota changes—especially in Eggerthella and Hungatella—mediate that association.
Design, setting, and participants
This multicenter cohort study used cross-sectional data from the Marburg–Münster Affective Cohort in Germany. Participants aged 18 to 65, recruited from the general population and primary care between September 2014 and September 2018, included patients with MDD and healthy controls.
Main outcomes and measures
Analyses used multivariable regression and ANOVA to test associations between soft drink consumption and MDD diagnosis and symptom severity, controlling for site and education. Microbiome analyses examined Eggerthella and Hungatella abundance, and mediation tests assessed whether microbiota differences explained the link between soft drinks and MDD.
Results
The study included 405 patients with MDD (67.9% female; mean age 36.4 years) and 527 healthy controls (65.5% female; mean age 35.3 years). Overall, soft drink consumption predicted MDD diagnosis and greater symptom severity, with stronger effects in women. In women, higher consumption correlated with increased Eggerthella abundance, and mediation analyses indicated that Eggerthella partially mediated the association between soft drink intake and both diagnosis and symptom severity.
Conclusions and relevance
This cohort study suggests that frequent soft drink consumption may contribute to MDD risk through alterations in the gut microbiome, notably involving Eggerthella. Public health efforts to reduce soft drink intake and strategies that target microbiome composition may help lower depression risk, particularly among susceptible groups.