A recent study conducted by German researchers revealed a clear link between daily soda consumption habits and mental health, finding that even moderate soda intake can alter gut microbiota in ways that increase the risk of depression, especially among women.

According to the study published by “News medical life science” citing JAMA Psychiatry, soda consumption is linked to obesity and diabetes due to its high content of empty calories, mostly simple sugars like glucose and fructose, which raise blood sugar levels. It is also associated with higher rates of depression.

The German study involved 405 patients diagnosed with major depressive disorder (MDD) and 527 healthy individuals, selected from the Marburg-Münster Affective Cohort, with most patients and controls being female.

The study explains that sodas contain large amounts of sugar that are difficult for the gut to absorb, promoting the growth of certain bacteria that typically cause inflammation and weaken the intestinal epithelial barrier, impairing mucosal immune defenses and allowing bacteria and their products to remain in the gut lumen.

Increased pro-inflammatory bacteria promote systemic and neuroinflammation, linked to anxiety and learning difficulties, especially in adolescents. Conversely, a diet that promotes production of anti-inflammatory short-chain fatty acids by beneficial gut bacteria protects the intestinal barrier and combats inflammation.

Previous studies also showed that higher soda consumption is linked to increased risk of depression, surprisingly not seen with sugary solid foods. Research also indicates that the gut microbiome is a key factor in major depression.

Soda consumption predicted higher rates of major depression diagnosis, with approximately an 8% increased likelihood of severe depression for each unit increase in soda intake. Those consuming larger amounts were more prone to severe depression.

These associations were driven by female participants, with women having about a 16% higher chance of severe depression. No association was observed in men.

Depressed patients had a higher average body mass index (BMI) compared to controls, yet the pattern remained consistent even after adjusting for BMI and antidepressant use.

BMI did not affect this association, which was not observed in men. Moreover, the gut microbiome of depressed women showed lower overall diversity and less balanced species distribution, with some species dominating others, a pattern not seen in men.

These findings highlight the need to raise consumer awareness about the mental health risks of soda consumption and support policies restricting its marketing and availability. Physical activity alone is insufficient to offset its effects. Notably, even moderate consumption—one or two sodas daily—is linked to health deterioration.

The reason for the negative effect of soda, predominantly in women, remains unclear. However, these results emphasize breaking the cycle of soda consumption and depression, as both impair normal metabolism. The relationship may be bidirectional; depressed individuals might consume more soda, so causality cannot be confirmed from this observational study.