Do we really have a second brain?

Gut and Bowel Health

Learn more about how your gut and brain are connected


Emily Condon
BSc (Hons) Biological Sciences

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Although we are all familiar with the sayings ‘trust your gut’, feeling ‘butterflies in your stomach’ and going through a ‘gut-wrenching experience’, many of us are unaware that these sensations are the result of a network of millions of neurons that line our guts, a network so extensive that scientists have nicknamed it our "second brain". 

The gastrointestinal (GI) system has its own nervous system, the enteric nervous system (ENS). The ENS is a mesh-like structure of neural tissue that does much more than just handle digestion or inflict the occasional nervous pang. It controls local blood flow, mucosal secretion and transport as well as modulating the function of our immune and endocrine systems.

How does our gut communicate with our brain? 

The 2 organs are connected physically and biochemically. The vagus nerve is the longest of the cranial nerves and physically unites the gut and brain. This nerve oversees a vast array of important bodily functions, including digestion, heart rate, immune response and mood. The gut is able to produce chemical messengers such as the neurotransmitter serotonin, which is best known as the “feel-good” neurotransmitter; in order to be able to communicate with the brain biochemically.

Bacteria also play a role in the gut-brain connection. Bacteria live throughout our bodies, and while many bacteria we encounter are associated with disease, the ‘good’ bacteria in our guts have a huge impact on our health and wellbeing. They aid digestion by producing metabolites bile acids and short-chain fatty acids. They are able to synthesise various neurotransmitters and vitamin K as well as modulating normal immune responses by protecting us against harmful bacteria.

How can I keep my gut healthy?

There is ongoing scientific research to show that an unhealthy gut can contribute to a wide range of health issues including diabetes, obesity and autoimmune conditions. Eating a well-balanced diet can help to keep your gut healthy.

  • Avoid highly processed foods as they can increase inflammation levels in the gut 
  • Eat fermented foods such as yoghurt, sauerkraut and kombucha as they contain healthy bacteria.
  • Eat prebiotic foods as they contain a type of fibre that stimulates the growth of healthy bacteria. Prebiotic-rich foods include artichokes, garlic, onions, bananas and asparagus.
  • Incorporate more whole grains into your diet, as they contain fibre and beneficial carbohydrates like beta-glucan

Scientists are only just beginning to understand the importance of the gut to our overall health and wellbeing, including out mental health. We expect to see more and more research over the coming months and years that sheds even more light on ways in which we can help our guts to keep us healthy.


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