Belly and brain - what’s the link?

As you might well know, gut health is a hot topic at the moment. It’s emerging that the bacteria inside us could have an impact on everything from our immunity and our brains to our weight-loss efforts and heart health. In this blog, we’re going to explore the intriguing – and perhaps most surprising – link between the gut and the brain.

We talk about a "gut feeling." An instinctive response: something that you just know. Intuitively, we’ve known it for a while. Long before microbes were discovered, some philosophers and physicians argued that the brain and gut were partners in shaping human health and behaviour. Throwing it way, way back to Hippocrates...

‘Let food be thy medicine and medicine be thy food’  

Well, new research is showing that the age-old phrase "gut feeling" is surprisingly accurate. New studies point to the trillions of organisms in the human microbiome playing an unexpectedly huge role in our mental wellbeing.

Science time

The gut-brain axis refers to the physical and chemical connections between your gut and brain. The two organs essentially ‘chat’ chemically, through hormones specifically known as neurotransmitters, and physically, through the millions of neurons that line the gastrointestinal tract. This vast network is known as the enteric nervous system (ENS) and is also known as the second brain, and it’s becoming clear that the signals sent back and forth can influence our mood and mental wellbeing. This bidirectional superhighway provides constant updates on the state of your affairs at both ends.

Or very simply...

-> A healthy human might lead to a less stressed gut.

->A healthy gut may result in a less stressed individual.

The gut is the only organ in our body to have its own "brain," and now we’re starting to understand why that is. Is it just to manage the process of digestion? Or could it be to listen to the trillions of microbes residing in the gut?

Gut health and mental health

Evidence is emerging that the ENS influences our mood and even plays a role in depression. Exactly how is still unclear, but scientists' efforts are currently focused on one of the many neurotransmitters found in the ENS. Heard of serotonin? It’s otherwise known as the "happy hormone" because it regulates (you guessed it) happiness.

Serotonin imbalance has been implicated in depression for a long time, which is why it is the target of several antidepressants. Yet, it’s estimated that over 90% of the body’s serotonin is made in the gut, and the amount of serotonin produced is deeply influenced by what we eat and the state of our microbiome.

A number of recent studies have shown a significant disparity in the composition and diversity of gut bacteria between healthy and depressed patients, with the depressed patients having fewer anti-inflammatory bacteria and a reduced diversity of the microbiome.


An unhealthy gut is just one of many possible causes of mental illness, and so while changes to the microbiome might bring relief to some, it mightn’t help all.

Having said that, just read our other blogs in the ‘Gut Health’ section to find out the many other reasons a diverse gut microbiome is so important, and how to help yours!

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