Posted on 07.15.22

Depression linked to gut bacteria

Tags

Depression linked to gut bacteria

A study involving thousands of people in Finland has revealed that a bacterium called Morganella could be causing depression. In this study, a bioinformatician at the Baker Heart & Diabetes Institute (G. Meric) did the analysis for this 40-year health study of 6000 participants in an effort to track down the causes of chronic depression. The study reviewed their gut microbes and had detailed information from the participants about their lifestyles, prescriptions, and health. The data was reviewed for clues as to how a person’s diet and genetics may affect their gut microbiome. They found that 2 parts of the genome influenced which microbes were present in the gut. One involved the gene for digesting lactose, and the other helps specify blood type.

When it came to depression, the 2 bacteria that caused infections in hospitalized patients were Morganella and Klebsiella, and they seemed to play a causal role. Morganella was significantly increased in a microbial survey of the 181 people in this study who later developed depression. This study was unique in that it made the connection between increased levels of this bacterium, and the patients who were being treated for depression.

Morganella has been implicated in depression before. In 2008, researchers reviewing a link between depression and inflammation found depressed individuals have a stronger immune response to chemicals made by Morganella and other Gram-negative bacteria found in the gut. This latest study seems to be more proof that the inflammation caused by these gut microbes could be influencing our mood.

As there are many forms of depression and many ways that microbes could be involved, the most promising way would be that this missing microbe could be given as a supplement, but it is more challenging to figure out how a certain bacterium could be removed from the gut to relieve symptoms. We are looking forward to learning more from future studies on this exciting area of research.

References

Qin Y et al (2022)  Combined effects of host genetics and diet on human gut microbiota and incident disease in a single population cohort. Nat. Genet. 54:134-142 PMID 35115689

Pennis Z (2022) Gut microbe linked to depression in large health study. Science.org Link.