Study finds groups of bacteria can either help or hurt mental health
The theory that the balance of specific bacteria in the gut might affect a person’s mental health is looking more and more likely.
A new Belgian study suggests that not only can higher levels of specific groups of gut bacteria increase the risk for depression, but increased concentrations of other bacteria could also conversely improve a person’s overall mental health.
The team from the Flanders Institute for Biotechnology says theirs is the first population-level study to identify a link between gut bacteria and mental health. Other studies either relied on smaller numbers of participants, animal trials, or clinical trial participants.
In the study, published in the journal Nature Microbiology, the researchers evaluated participants in two sets of trials.
In the first trial, the researchers evaluated the microbiome data from fecal samples of 1,054 individuals participating in the Flemish Gut Flora Project. They then compared the data against the participant’s clinical history of depression.
Using this process, the team says they were able to identify groups of microorganisms that either positively or negatively related to the mental health of the individual. In particular, they found that low levels of two bacterial genera, Coprococcus and Dialister, were tied to higher depression symptoms, regardless of antidepressant treatment.
The researchers then replicated the findings in a separate group of 1,063 individuals in the Dutch LifeLinesDEEP study and a smaller group of individuals diagnosed with depression at the University Hospitals Leuven in Belgium.
“The relationship between gut microbial metabolism and mental health is a controversial topic in microbiome research,” said study leader Professor Jeroen Raes.
“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. In our population-level study we identified several groups of bacteria that co-varied with human depression and quality of life across populations.”
The analysis also discovered bacteria which produced a chemical which correlated to better overall mental health in the participants.
“Our toolbox not only allows 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,” she said.
“For example, we found that the ability of microorganisms to produce DOPAC, a metabolite of the human neurotransmitter dopamine, was associated with better mental quality of life.”