Women, it is time to limit your intake of soft drinks.  New research shows soft-drink consumption is linked to a higher risk for major depressive disorder (MDD), especially in women.

Investigators found that higher soft-drink consumption increased the risk of MDD by 16.7% with a much stronger effect in women. The results of the new study, published online on September 24, 2025 in JAMA Psychiatry, can be found here.

The link between soft drink consumption and MDD diagnosis, as well as symptom severity, remained significant in women after controlling for body mass index (BMI), antidepressant use, education, and total calorie intake. The relevant effects were simply not seen in men.

It remains unclear why the relationships are stronger in women, but hormonal differences certainly play a role.

What’s causing this?  

It appears the pro-inflammatory bacterium Eggerthella loves soda as much as you do, as its abundance in the gut microbiome was correlated with soda intake.

The Eggerthella species, typically present at low levels in a healthy gut microbiome, have been consistently linked to MDD, likely due to gut-brain mechanisms. This is consistent with recent research on the “microgenderome” that suggests gut microbiota interact with sex hormones.

Multiple epidemiological studies have linked soft-drink consumption to depression. One study showed women that regularly consumed soft drinks were 34% more likely to develop MDD after 4 years; a meta-analysis of 10 studies involving ~300,000 individuals also showed a definitive link between depression and soft-drink consumption.

Remember that soft drinks are ultra-processed and are either rich in simple sugars like glucose and fructose, or contain artificial sweeteners (think aspartame or saccharin), which, if consumed excessively can lead to a higher risk of stroke, heart disease, and death overall.

In the study, there was no difference between sugar- and artificially-sweetened soft drinks, but the researchers noted that the analysis wasn’t designed to tease that apart.

Thank you to the article “Soft Drinks’ Effect on the Gut Tied to Increased Risk for Major Depression” by Pauline Anderson as it appeared in Medscape Medical News, September 30, 2025.