The gut-brain axis: Are the gut & brain really connected?

That flutter you get when you’re nervous is more than just a feeling in the pit of your stomach. It's a sign of the fact that our brain and gut are actually inextricably intertwined in ways we still don’t fully understand. Studies have found that an entire communication system exists between the brain and gut, which is commonly referred to as the gut-brain axis.²

In this article, we’re going to look at the gut and brain connection, how it works from our current understanding, why it’s important, and what you can do to influence it.

The gut-brain axis is a two-way communication pathway that exists between the gut and the brain.² Not only does the brain have a connection to the gut, but the gut has access to the emotional and cognitive centres in the brain too.²

This means that conditions in the gut could have an impact on what the brain does and how we feel, and conversely, how we feel emotionally can impact how the gut functions.

Emerging research suggests that the gut-brain axis has so many effects on our health, both mental and physical, so it is really important to take good care of your gut health.

Here are just some of the ways that the gut and brain connection is important: 

Due to the link between the enteric nervous system (the part of the nervous system that controls our gut) and the central nervous system (the part of the nervous system that controls our brain) now being established, some medical professionals are choosing to offer treatments that communicate with both ‘brains’, so to speak.

For instance, gastroenterologists may prescribe certain antidepressants (SSRIs) for IBS — not because they think the problem is all in a patient’s head, but because these medications calm symptoms by acting on nerve cells in the gut. 

There are several ways you can enhance your gut health. They include:

The microbiome is an essential component of the gut, without actually being part of its anatomy. It is made up of bacteria that we have a symbiotic relationship with.

Bacteria perform functions for us, such as making neurotransmitters, training the immune system and digesting food and, in return, we provide them with food in the form of fibre, also known as prebiotics, from our diet.⁹

In order to keep the microbiome thriving, you need to feed it well.¹⁰

Vegetables, beans, and whole grains all have good amounts of fibre in them and can help to feed the friendly bacteria in our gut, acting as prebiotics. We’ve got a full round-up of the best foods for your gut health here.

As well as prebiotics, we can also take probiotics either as ready-made products or from fermented foods. Fermentation produces lactic acid bacteria in foods, like yoghurt and kefir, which populate the gut when eaten and may have a positive effect on metabolism.¹¹

A study by UCLA in 2013 examined 36 women split into three groups: those who ate two bacteria-containing yoghurts every day for a month, those who ate a dairy product without any bacteria, and a control group.¹²

Results showed that those in the bacteria yoghurt group experienced changes in the part of the brain that processes emotions linked to visual stimuli, with some decrease in activity.¹²

Some scientists believe that the research could one day lead to so-called psychobiotics – medicines based on bacteria – being used as treatments for mood disorders, including depression.¹³

To get a broad range of bacteria populating your gut, you need to come into contact with a lot of different environments. There’s a big difference between the bacteria that live in cities compared to those that live on farms with livestock, for instance.¹⁴

Taking a trip to the countryside – as well as having a nice day out can actually improve our risk of allergies because exposure to this kind of bacteria helps to train our immune systems to tolerate non-harmful bacteria and substances.¹⁵

Physical activity can improve conditions in the gut so that anti-inflammatory bacteria can thrive.¹⁶

Exercise could even affect the types of bacteria that thrive in your intestines. Especially if you can combine it with getting into a different environment – running in the woods versus running on a treadmill, for example.¹⁷

It can also prevent constipation by making sure the muscles in the gut keep contracting and moving food through.¹⁸

Early research on animals has found that stress can impact the composition of the gut microbiota and that this can have an effect on the host (i.e. the person experiencing stress).²

A number of studies using germ-free mice (mice who have no microorganisms living in them) have shown a link between microbiota and anxiety-like behaviours. Further research has shown that some microbiota can improve anxiety-like behaviours and increase the production of dopamine and serotonin, demonstrating the potential role of gut microbiota in mood and behaviour.¹⁹ More research is needed in clinical human studies to understand the role of the gut microbiota on mood.

Research has found, and continues to find, that the brain directly affects our stomach and intestines. More specifically, the brain and gastrointestinal system are intimately linked, with both signalling to each other via a connection that can go both ways.

Managing your stress levels, eating healthily, and taking good care of your gut, particularly your gut bacteria, has been proven to play an instrumental role in improving overall gut and brain health. If you’re looking to change up your diet, we’re on hand to help.

If you are experiencing uncomfortable symptoms related to your gut health, it is best to speak to your GP. They will be able to offer you tailored advice and support based on your symptoms.

Want to know more about gut health? We’ve got a full guide to the gut microbiome, as well as more information on digestion and a guide to having a happy gut.