RESEARCHERS from the University of Gothenburg and Swedish probiotic company BioGaia AB have identified specific bacteria present in the gut that can produce serotonin.
While best known as a neurotransmitter in the brain, over 90% of the body's serotonin is found in the intestine, produced by human cells in the gut where it controls intestinal movements via the enteric nervous system, among other roles.
Previous research has shown that the composition of bacteria in the intestinal microbiota affects how much serotonin is produced, but until now it has been unclear whether intestinal bacteria themselves can form biologically active serotonin.
In the current study, the researchers identified two bacterial strains that together can produce serotonin - Limosilactobacillus mucosae and Ligilactobacillus ruminis - which belong to the former genus known as Lactobacillus.
The researchers discovered that people with irritable bowel syndrome (IBS), a disorder of the gut-brain interaction, had lower levels of L. mucosae - which has the enzyme required for serotonin production - in their stool compared to healthy individuals.
"It is incredibly fascinating how the bacteria in the intestine can produce bioactive signalling molecules that affect health," said Professor Fredrik Backhed, one of the leaders of the study.
"Our results indicate that certain gut bacteria can produce bioactive serotonin and thus play an important role in gut health and open new avenues for the treatment of functional bowel diseases such as IBS," Professor Backhed added.
The discovery could potentially aid understanding of how the gut microbiome signals the brain and behaviour, and open the way for the development of innovative probiotic products in the gut health and mental health spaces.
Read the study HERE. KB
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