Summary: A new study shows that sugary drinks don’t just affect physical health—they may also raise the risk of depression in women by disrupting the gut microbiome. Researchers found that high consumption of soft drinks was linked to both a greater likelihood of major depressive disorder and more severe symptoms, particularly among women.
The effect appears tied to an increase in Eggerthella bacteria, which have been linked to depression in earlier studies. These findings suggest nutrition-based interventions could play a role in preventing or treating depressive disorders.
Key Facts
- Gender-Specific Risk: Women consuming sugary drinks had a 17% higher risk of depression.
- Microbiome Link: The bacterium Eggerthella was more abundant in women with high intake.
- Therapeutic Potential: Diet and probiotic strategies could help reduce depressive symptoms.
Source: DZD
A new study involving the German Center for Diabetes Research (DZD) provides strong evidence that sugary drinks affect not only metabolic but also mental health – especially in women. This effect is probably mediated by the sensitive microbiome of the intestine.
As is well known, people who regularly consume sugary drinks not only have an increased risk of obesity, type 2 diabetes, cardiovascular disease and cancer. There is an increasing number of studies that are now showing that soft drinks can also affect mental health. So far, however, it was unclear whether there is a direct relation to major depressive disorder (MDD) and which biological processes might be involved.
Soft Drink Consumption Associated with Higher Risk of Depression
To answer these questions, researchers analyzed cross-sectional data from the Marburg-Münster Affective Cohort (MACS). The study examined adults between the ages of 18 and 65 who were recruited from the general population and primary care between 2014 and 2018. The researchers included a total of 932 people, 405 of whom were patients with major depression disorder and 527 were healthy controls.
The analyses showed a correlation between soft drink consumption and both the diagnosis of depression and the severity of the symptoms. This correlation was particularly pronounced in women: Among them, high consumption was associated with a 17% higher probability of depression (odds ratio 1.167) and more severe symptoms.
Changes in the Microbiome as a Key Factor
But how could the effect be conveyed? Here, too, the study provides a possible explanation: In women who regularly drank sugary soft drinks, the researchers found a significantly increased number of bacteria of the Eggerthella genus in the intestine. Earlier studies had shown that Eggerthella is more common in people with depression.
The current study now provides the first convincing evidence that this bacterium possibly plays a mediating role – as a biological link between the consumption of soft drinks and the development of depressive symptoms.
“Our data suggests that the relation between soft drinks and depressive symptoms arises via the influence of the microbiome,” says study leader Dr. Sharmili Edwin Thanarajah from the University Hospital Frankfurt and the MPI for Metabolism Research Cologne, an associated partner of the German Center for Diabetes Research (DZD).
Sugary drinks such as cola or lemonade not only contain glucose and fructose, but also numerous additives – including preservatives and artificial sweeteners. This combination can disturb the delicate balance in the intestinal microbiome. Inflammation-promoting bacteria are favored, while the production of protective short-chain fatty acids decreases. Animal studies show that such changes can trigger inflammatory processes in the nervous system and thus increase depressive behavior.
It is striking that this correlation appears to be sex-related. In men who regularly consumed soft drinks, the researchers found neither an increase in Eggerthella nor a correlation with depressive symptoms. It is still unclear why this effect only occurs in women. Hormonal differences or sex-related reactions of the immune system possibly play a role.
The Microbiome as a Therapeutic Target?
“The study results open up new perspectives for the prevention and treatment of depressive disorders,” comments DZD researcher Rachel Lippert from the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE).
“Microbiome-based approaches – such as targeted nutritional therapies or probiotic strategies – might help to effectively alleviate depressive symptoms in the future.”
The researchers therefore argue that the influence of nutrition on mental health should be more strongly integrated into educational campaigns, care concepts and prevention programs.
“Changes in the microbiome can be influenced by diet – and are therefore a potential therapeutic target,” explains Edwin. “Even small adjustments in consumer behavior might have a big impact – especially when considering the widespread consumption of soft drinks.”
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.
“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
The bitter taste of sweet drinks: Increased consumption of soft drinks is linked to depression via gut microbiota alterations
Importance
Soft drink consumption is linked to negative physical and mental health outcomes, but its association with major depressive disorder (MDD) and the underlying mechanisms remains unclear.
Objective
To examine the association between soft drink consumption and MDD diagnosis and severity and whether this association is mediated by changes in the gut microbiota, particularly Eggerthella and Hungatella abundance.
Design, Setting, and Participants
This multicenter cohort study was conducted in Germany using cross-sectional data from the Marburg-Münster Affective Cohort. Patients with MDD and healthy controls (aged 18-65 years) recruited from the general population and primary care between September 2014 and September 2018 were analyzed. Data analyses were conducted between May and December 2024.
Main Outcomes and Measures
Primary analyses included multivariable regression and analysis of variance (ANOVA) models examining the association between soft drink consumption and MDD diagnosis and symptom severity, controlling for site and education, and Eggerthella and Hungatella abundance, controlling for site, education, and library size. Mediation analyses tested whether microbiota abundance mediated the soft drink–MDD link.
Results
A total of 405 patients with MDD (275 female patients [67.9%]; mean [SD] age, 36.37 [13.33] years) and 527 healthy controls (345 female controls [65.5%]; mean [SD] age, 35.33 [13.13] years) were included.
Soft drink consumption predicted MDD diagnosis (odds ratio [OR], 1.081; 95% CI, 1.008-1.159; P = .03) and symptom severity (P < .001; partial η2 [ηp2], 0.012; 95% CI, 0.004-0.035), with stronger effects in women (diagnosis: OR, 1.167; 95% CI, 1.054-1.292; P = .003; severity: P < .001; ηp2, 0.036; 95% CI, 0.011-0.062).
In women, consumption was linked to increased Eggerthella (P = .007; ηp2, 0.017; 95% CI, 0.0002-0.068), but not Hungatella abundance. Mediation analyses confirmed that Eggerthella significantly mediated the soft drink–MDD association (diagnosis: P = .011; severity: P = .005), explaining 3.82% and 5.00% of the effect, respectively.
Conclusions and Relevance
In this cohort study, it was found that soft drink consumption may contribute to MDD through gut microbiota alterations, notably involving Eggerthella. Public health strategies to reduce soft drink intake may help mitigate depression risk, especially among vulnerable populations; in addition, interventions for depression targeting the microbiome composition appear promising.
