Micro-organisms – the connection between gut and brain


Our second brain?

Last week we had a little exploration of fermented or living foods, delicious and wonderful for our digestive health. This week I’d like to take a look at one of the major areas of research at the moment in the world of the micro-organism and the gastro intestinal tract. The connection between the GIT and our minds.

A great place to start is the connection that we all understand. At some stage most of us would have experienced ‘butterflies’ in our stomach before an exam or big event. Likewise, during times of high stress or significant change experiencing diarrhoea or constipation is not an uncommon side effect.

On an anatomical level our GIT functions very much like a second brain. Our digestive tract contains approx 100 million neurons in a system known as the enteric nervous system. Most of the chemicals which control the brain are also found functioning within this enteric nervous system. This includes important neurotransmitters such as serotonin, dopamine and GABA, often common targets for conventional mental health medications. The enteric nervous system connects with the brain via one of our major nerves, the vagus nerve. Until fairly recently it was understood that communication travelled primarily from the brain to the GIT. This has now changed as research has shown that the GIT can also signal to the brain and has an important role to play.

A current area of investigation is the human microbiome. Our microbiome is what we would discover if someone was sent in to carry out a census in our digestive tract. What bacteria live in side each our unique environments? Where do they like to live? What do they do for work? How many is there and what do they like to eat? Understanding of each unique bacteria’s function and role in our digestive health is a long way off yet, if ever. Despite that, there is some good evidence showing the our microbiomes effect the health of the GIT and as such also the communications between the digestive tract and the brain.

Scientific investigations with humans and animals have shown many connections between digestive health and mental health. Inflammation of the digestive tract, bacterial overgrowth, leaky gut and dysbiosis (imbalance of digestive bacteria) have all been cited as contributing factors in autism, schizophrenia, depression, obsessive compulsive disorder and many other mental health issues. Use of probiotics and fermented foods has shown positive changes in many of these people reinforcing the effect of our GIT on the health of our mind.

Article by Damian Harrison, Naturopath from Chamomile Naturopathy , Bellingen.