5. Feb, 2017

The Gut Microbiome and mood

90-95% of human serotonin is produced by enterochromaffin (EC) cells in the gut, and is necessary for healthy gut function. You might be surprised to learn that only a very small amount is created in the brain, I certainly was.

A recent study found that gut microbes regulate levels of serotonin in the colon and blood, and that these spore-forming bacteria stimulate the production of colonic serotonin through the products they create.

Given the gut-brain axis, this study adds to the growing evidence base that the human microbiome effects mood. The link between our microbiota and anxiety and depression has been established, now studies are focusing on the mechanism - how?

But what is this gut-brain axis we keep hearing about? It's just the relationship between the gastrointestinal (GI) tract and the brain - the communication that takes place between them. When you hear 'axis' being used in med-science, just think 'link'. The details of the link are not as important (except to nerds like me) as the fact that it exists.

The more we discover about the links between our gut microbiota and human health, the more the old adage 'You are what you eat' takes on new meaning. What you feed your gut microbiota is key. The link between primarily vegetarian diets and good health is no accident. So far the evidence is that beneficial gut bacteria love fruit, veg & pulses. There are benefits in dairy products as well. If you consider the Mediterranean diet, cheese is a vital component. What is a Greek salad without feta cheese?

The term 'mindful eating' is being bandied about a lot lately, mostly about the amount of food people are consuming. I would suggest that the quality of the food is considerably more important, and if we focus on that, the amount will naturally decrease as we eat more nutrient dense food - without the guilt trips and calorie counting that lead to eating disorders.


Yano, Jessica M, Yu, K, Donaldson, Gregory P, Shastri, Gauri G, Ann, P, Ma, L, Nagler, Cathryn R, Ismagilov, Rustem F, Mazmanian, Sarkis K & Hsiao, Elaine Y 2015, 'Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis', Cell, vol. 161, no. 2, pp. 264-276.