Pharmacy Daily | Dispensary Corner 26 Sep 25

IS IT time to call time on sugary fizzy drinks?

Having already been linked to diabetes, obesity, dementia and dental problems, new research conducted in Germany has found a link between soft drink consumption and increased risk of developing depression.

The link was put down to effects on the gut microbiome, where soft drinks appeared to raise levels of Eggerthella, a type of gut bacteria found to be more abundant in people with depression.

The study included around 400 people with major depressive disorder and 500 people without.

Participants were surveyed about mental health symptoms and soft drink intake, and also collected stool samples.

Soft drink intake predicted the diagnosis of depression, and the researchers also found an abundance of Eggerthella in women with depression, though not in men.

Eggerthella has been shown in mice to deplete tryptophan, an amino acid that's needed to produce the 'feel-good' hormone, serotonin.

"These findings underscore the role of diet in depression, and highlight the gut microbiome as a key mediator," said Dr Sharmili Edwin Thanarajah, of University Hospital Frankfurt.

The bad news for those who want to switch out sugary drinks for artificially sweetened ones is that they also disrupt the gut microbiome, with the authors suggesting sticking to water.