What is the brain-gut connection?

What is the brain-gut connection?

By Ishma Alvi.

We talk about ‘gut instincts’, and have experiences we describe as ‘gut wrenching’. It now looks like these aren’t simply visceral sensations but indications of an actual connection not simply between mind and body, but specifically between the brain and gut.

Before we delve deeper into this connection, let’s clarify what the gut actually is. It’s the gastrointestinal tract; the long tube-like structure that starts at the mouth and ends at the anus. The principal function is to digest and absorb nutrients and excrete waste. But it also has an influence on the function of the immune system. Another function of the gut intersects with psychology – the part where the gut and brain ‘talk’ or the gut-brain axis.

The gut-brain axis is the connection between the gut and the brain. Just like the brain (aka The Big Brain) is a key part of the central nervous system, the gut (aka The Little Brain) is a part enteric nervous system, and functions like a brain; maybe not producing thoughts and feelings in and of itself but definitely contributing to them[i]!

One way the brain and gut ‘talk’ to each other is through that part of the brain we call the limbic system. The limbic system functions a little like an alarm system and when triggered by what it perceives as a threat (an angry dog or an irate boss), it releases hormones and chemicals, including adrenalin. This leads to a chain reaction of physiological reactions that allow us to either fight or flight and one of these reactions is an increase of gastric acid in the gut. Which is why the expression “I was so scared I *insert polite term for release of faeces* myself!” isn’t just an expression.

If we are constantly stressed, with that limbic response going into overdrive, we might start having ongoing gut issues; such as bloating, cramping, indigestion, diarrhoea. Often, IBS and stress (or anxiety) go hand in hand.

More recent research suggests that in some cases it may be the other way around-poor gut health leading to increased vulnerability to stress or anxiety [ii].

Either way stress and gut issues seem to go together; whichever comes first!

But as important as understanding the connection, is understanding how to manage the connection in helpful ways. Here are some simple ways to do that:

  1. Know Your Stress Patterns

There are patterns of behaviour that occur when we are stressed, which can impact mental and gut health. For example, you are stressed about a work deadline, and so meals are rushed, with speed and efficiency rather than nutrition being the focus. If the gut is already sensitized with heightened acid, a rapidly declining diet, and rushed eating will be an additional burden.

Another pattern might be electing to work rather than exercise, thinking it’ll save time and help ‘get over’ the stress faster. So, you stay at your desk, your gut full of poorly chewed, low nutrition food. This further exacerbates gut issues, which further increases stress.

Other behaviour patterns may further exacerbate this, such as poor sleep. Typically, stress impacts sleep, but poor gut motility and bloating further impacts it and a little downward spiral starts:

Stress -> Poor Diet -> Little Exercise -> Poor Sleep -> More Stress

Knowing what you usually do when you’re stressed and investing more in your self-care when you are stressed can help reduce longer-term effects of poor gut and therefore impacted mental health.

2. Build Good Gut Habits

A little motif that shows up a lot in my therapy sessions – discipline is for sprints and habits are for marathons. What that means is that exerting conscious discipline is like flexing a muscle, something that is fatiguing and unsustainable for longer periods. Instead, choose a sustainable way you could build on gut health, that can be easily slotted into your daily life and sustained over the long term (aka the rest of your life!). Maybe swapping out one of your coffees, or ditching that one food you know causes digestive distress, going for a lunchtime walk or simply introducing a probiotic and a probiotic [iii] you like into your diet.

3. Relaxation for The Gut-Brain Axis

Relaxation exercises, whether guided meditation, yoga, deep breathing, or simply stretching can be beneficial for stress; stress that impacts both The Big Brain and The Little Brain! Using habit-forming principles (easy, quick, pleasurable and sustainable) pick relaxation exercises you can do on a daily basis.

Remember: mental health (both gut and brain health) isn’t any different to dental health. Think about it you rarely forget to brush your teeth no matter how stressed, nor do you plan your mornings and evenings around teeth brushing.

You just do it.

So, just do it…care for your gut.

Your brain will thank you for it.


This Blog was written by Ishma Alvi. To learn more about Ishma’s experience, click here.

To book an appointment with Ishma, or one of our other Psychologists click here.



(i) https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection

(ii) https://www.health.harvard.edu/diseases-and-conditions/the-gut-brain-connection

(iii) https://www.healthline.com/nutrition/probiotics-and-prebiotics#benefits

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