The gut and mental health

Round & About


It is not a new concept that a ‘gut brain’ axis exists and I have touched on this subject before in previous columns.

Serotonin is a neurotransmitter that regulates mood, appetite and sleep; when there are appropriate levels in the brain we feel relaxed and positive. This is the principle behind selective serotonin reuptake inhibitor drugs (SSRIs), to increase levels of serotonin available to the central nervous system. It is the gut, not the brain, however that is responsible for over 90% of total serotonin production.

In the gut, serotonin controls how ‘regular’ you are and it is the balance of the bacterial species in our gut that appears to play a significant role in the amount of serotonin produced. This might well explain not only why a significant relationship exists between individuals presenting with irritable bowel syndrome (IBS) and depression, but also why when doctors prescribe SSRIs for depression, those presenting with IBS often see improvements in digestive function.

A new study has found evidence in humans (not rodents as was the case until now) that our emotional responses, including anxiety and depression vary considerably depending on bacterial balance in the gut. The results not only suggest a strong link between the bacterial composition of our guts and feelings, but that the balance may change the physical structure of the brain by either growing the frontal cortex or shrinking the hippocampus – areas of the brain involved in problem solving, emotional regulation and consciousness. Understanding that gut microflora can play such a huge role in chemical balance of the brain is one thing, but that these microbes might initiate physical changes in the brain is another! This may well be why in clinical practice I often see clients’ overall mental health and wellbeing improve as we identify and eliminate key food and environmental sensitivities and support overall gut health.

Call Mark BSc (Hons) BA (Hons) mBANT CNHC on 01183 219533 or visit