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Gut bacteria associated with depression

Certain bacterial strains in the gut may affect depression and quality of life, according to findings published in Nature Microbiology.

“The relationship between gut microbial metabolism and mental health is a controversial topic in microbiome research,” Jeroen Raes, PhD, of KU Leuven-University of Leuven and the VIB Center for Microbiology in Belgium, said in a press release. “The notion that microbial metabolites can interact with our brain — and thus behavior and feelings — is intriguing, but gut microbiome-brain communication has mostly been explored in animal models, with human research lagging behind.”

Raes and colleagues analyzed data from the Flemish Gut Flora Project, a large microbiome population cohort, to determine the association between microbiome features and quality of life and depression among patients with general practitioner-reported depression (n = 1,054).

The researchers found that Faecalibacterium and Coprococcus bacteria, which produce butyrate, a short-chain fatty acid that increases the defense barrier and reduces intestinal inflammation, were consistently tied to higher quality of life indicators.

Additionally, patients with depression had lower levels of Coprococcus and Dialister bacteria, irrespective of antidepressant treatment.

The bacteria community type linked to depression in this study was similar to that of a community constellation or enterotype that was found to be common among patients with Crohn’s disease in prior research, according to Raes.

“This finding adds more evidence pointing to the potentially dysbiotic nature of the Bacteroides2 enterotype we identified earlier,” Raes said. “Apparently, microbial communities that can be linked to intestinal inflammation and reduced wellbeing share a set of common features.”

The researchers also found that microorganisms that produce DOPAC, which is a metabolite of dopamine, was linked to better mental quality of life.

These results were validated using data from the Dutch LifeLinesDEEP cohort and a cohort of patients with clinical depression at the University Hospitals Leuven, Belgium.

“Our toolbox not only allows researchers to identify the different bacteria that could play a role in mental health conditions, but also the mechanisms potentially involved in this interaction with the host,” Mireia Valles-Colomera, PhD student at KU Leuven-University of Leuven and the VIB Center for Microbiology, said in the release.

These data need to be confirmed, but can help guide future human microbiome-brain research, according to the researchers. – by Alaina Tedesco

Disclosures: The authors report no relevant financial disclosures.