What is Gut Brain Axis?

Can the bacteria in our gut affect our brain function?

The connection between our brain and our gut is already part of how we describe experiences – having a “gut-feeling” a “gut-wrenching” moment or feeling nervous with “butterflies” in the stomach. These expressions have become commonplace for a reason. We now know there is a connection between our brain and our gut. Scientists call this connection the gut-brain axis – the two-way dialogue between the brain and the gut where information flows between the two organs.

There are three main communication channels between the brain and the gut:

1. the nervous system
2. the immune system
3. the endocrine system (hormones)

A key physical link that relays the information between the gut and the brain is the vagus nerve. This nerve relays information using molecules called neurotransmitters (chemical messengers). Approximately 80-90% of nerve fibres in the vagus nerve are going from the gut to the brain.

What role can specific gut bacteria play in the gut-brain axis?

Evidence shows that bacteria (also known as microbes) in the gut can act on the gut-brain axis and hence influence gut-brain communications.

The gut produces more than 90% of the serotonin found in your body – this is a neurotransmitter that can affect your mood and feelings of happiness and pleasure and research has shown that gut bacteria can impact its production in the gut.

Current research indicates that a gut with a healthy microbiota is a strong predictor of health and wellbeing.