Gut Health

What is the gut-brain axis?

November 1, 2023

We hear the term “gut-brain axis” often, especially in today’s world where the importance of the gut and its numerous functions are becoming more and more prevalent. But despite recognising the term, how many of us actually know what the gut-brain axis is? Do we know if the gut is actually connected to the brain? And what is the physical connection and why is it so important for our brain health? There are so many questions around this term, which today, we’re diving into. 

What is the gut-brain axis? 

The gut-brain axis is a bidirectional communication system that links the central nervous system with our enteric system, our endocrine system and our immune system. 


  • Central nervous system = the brain and spinal cord
  • Enteric nervous system = complex network of neurons found in our gastrointestinal tract
  • Endocrine system = responsible for managing our hormones
  • Immune system = complex network of organs, cells and proteins that defends the body against infection, whilst protecting the body’s own cells

This axis allows for constant and intricate communication between the gut and brain, playing a crucial role in various physiological and psychological processes.

How does the gut and brain communicate? 

The gut-brain axis communicates and is connected by the vagus nerve, the largest nerve within the human body. The vagus nerve is part of the autonomic nervous system, meaning that it is in control of the things we’re not ie. the heart, which automatically beats to pump blood around the body and supply us with needed oxygen. 

The vagus nerve is able to carry signals to and from the brain, enabling the gut to send messages to the brain and vice versa. This communication helps regulate the digestive system such as enzyme secretion which helps to break down the food we consume. 

As well as communication via the vagus nerve, the gut can also communicate with the brain via hormones. These are chemical messages sent into the bloodstream to tell your body what to do and when to do it. For example, when we eat, our bodies release hormones called ghrelin and leptin. These are both involved in the digestive process. Ghrelin increases our appetite whereas leptin suppresses hunger so that we know when to eat and when to stop.

You might have also heard of the gut microbiome. Our gut measures a combined (small and large intestines) length of 15ft, and is packed with a vast and diverse community of microorganisms known as the gut microbiota. These organisms, some good, some bad, play a huge role in the gut-brain axis by producing various chemicals that can affect brain function. The gut microbiome influences mood, behaviour and even cognitive function.

Why is the gut-brain axis so important?

The communication path between the gut and the brain is a continuous relationship. It’s vitally important in five key areas:

  1. Regulation of digestion: the gut-brain axis coordinates digestion and the absorption of nutrients, to ensure the proper function of the gastrointestinal system – that it runs smoothly and efficiently. 
  1. Regulation of mood and behaviour: research suggests that the gut-brain axis impacts our mood and behaviour. When the gut-brain axis is out of sync, conditions such as anxiety, depression and stress can be diagnosed. 
  1. Immune function: our gut holds 70% of our immune system and so the gut-brain axis plays a pivotal role in regulating its function. An imbalance in the gut can influence the immune system response, leading to autoimmune conditions such as thyroid disease and psoriasis. 
  1. Nutrient uptake and energy balance: via our hormones, the gut-brain axis is vital in regulating our energy intake and energy expenditure. By communicating with the brain, our brain then has the power to assess our nutritional status and adjust our intake accordingly. It does this by releasing the previously mentioned hormones of ghrelin and leptin. 
  1. Gut microbiota: the gut microbiome has gained significant attention over recent years. An imbalance in the gut microbiome – too many bad organisms and not enough good bacteria – can have a wide effect on our overall health including digestive issues, heartburn, bloating, sleep and skin issues. 

Understanding the gut-brain axis allows us to see why nurturing the gut-brain axis is so important. It plays a pivotal role in optimising both our bodies and brain health.The link between the gut and the brain continues to be investigated and researched so that over time, this complex system and all of its intricate connections can continue to be unravelled and widely understood to better our overall sense of wellbeing. 

To look after your gut health why not try making your own Kombucha or joining our gut-health challenge? Visit each article at: