Dutch studies link differences in intestinal flora to depressive symptoms

Two Dutch studies have found that people with depressive symptoms often have different intestinal flora. While the studies don’t prove a causal relationship between gut health and depression, the results could be the starting point for offering alternative treatments for depression, psychiatrist and researcher Anja Lok (Amsterdam UMC) said to the Volkskrant.

“Many patients have been helped by antidepressants or cognitive behavioral therapy, but not everyone. Hopefully, in the future, we can also treat them with probiotics or food. Or use intestinal flora analysts to predict who responds to which therapy,” Lok said.

Lok was involved in both studies, published in Nature Communications on Tuesday. Over 1,000 Rotterdam residents and 3,200 Amsterdam residents completed standardized questionnaires about depressive symptoms and sent feces samples to be tested.

The researchers found 13 bacterial strains that are more or less peasant in the feces of subjects with depressive symptoms. According to the researchers, the abnormal microbes may affect the brain through the substances they produce, such as glutamate, butyrate, and serotonin - substances that play an important role in the communication between brain cells.

“We cannot draw conclusions about cause and effect,” Lok stressed. “There is probably a trade-off, just like with sleep. If you don’t sleep well, you run a higher risk of depression; if you have depression, you often sleep worse.” Further research is needed.