Science has opened the door to the possible treatment of depression based on probiotics. And it is becoming increasingly clear that our microbiome not only seems to influence our well-being, but is also directly related to the development of depression.
Researchers from the Flemish Institute of Biotechnology and the Catholic University of Leuven came to this conclusion. The investigations carried out showed that people with depression had consistently low bacterial levels of the genera Coprococcus and Dialister. And that regardless of whether antidepressants were taken or not.
People with depression have low concentrations of intestinal bacteria of the genus Coprococcus and Dialister.
At the same time, people with a high quality of life and mental health showed increased populations of the bacteria Faecalibacterium and Coprococcus. These results were based on data and stool samples from over 1,000 people who participated in the Flemish Flora Project.
The study published in Nature Microbiology does not conclusively prove that intestinal bacteria can impair mental health. It would also be possible for the effect to work the other way round, i.e. the microbial environment in the colon could change as a result of depression.
But, how do intestinal bacteria communicate with the nervous system? The researchers found that the microorganisms studied could produce many neurotransmitters or precursors for substances such as dopamine or serotonin. Both dopamine and serotonin have complex roles in the brain and play key roles in the development of depressive symptoms.
If these preliminary results stand up to further testing, they could pave the way for novel treatments of mental disorders based on pro- and pre-biotics. Probiotics are special living microorganisms that are resistant enough to survive digestive processes in the stomach and small intestine and to reach the large intestine in sufficient quantities. Once there, they could increase the bacterial populations of those strains that are present in reduced concentrations during depression. This measure would restore the existing imbalance and specifically improve the depressive symptoms.
Pre- and pro-biotics could establish themselves as the basis for novel treatment methods for mental disorders.
However, the use of prebiotics would be based on a different therapeutic approach. For us, prebiotics are indigestible dietary fibres which can be fermented by intestinal bacteria and serve them as “food”. Special types of dietary fibre could be used to “feed” the desired bacterial populations and thus restore balance.
Clearly, a great deal of research still needs to be done before these solutions find their way into actual therapy. However, the first steps have already been taken. Two separate studies published in Nature Biotechnology report on more than 100 newly discovered intestinal bacteria whose DNA could be sequenced for the first time. These make an important contribution to the completion of the microbial “catalogue” and broaden our understanding of the human intestinal flora and the interaction between intestinal bacteria and the psyche.
