Can your gut health impact your mental health?

Key Points

• Gut health can impact brain health and vice versa
• ‘Gut-brain axis’ is the term used to describe this relationship
• Improving gut health may be beneficial for mental wellbeing

The recent spotlight on gut health has demonstrated exciting results and opened up many opportunities for further research. One of the most significant areas for potential is the gut health and mental health relationship. As we’ve learned, gut health can impact the wellbeing of the body and mind. But as it turns out, your mental health might also affect your gut health, and scientists call this relationship the gut-brain axis.

As an emerging area of research, the gut and mental health relationship is promising. To understand how improving your gut health may lead to a healthier mind, we need to learn about the amazing gut-brain axis.

The gut-brain axis: how it works

The gut-brain axis refers to the relationship between the central nervous system, which controls the brain and spinal cord, and the enteric nervous system, which is in charge of the digestive system.

The connections between the gut and the brain occur with sensory and motor nerves that link these systems. And the complexity of the enteric system has earned it the label of our ‘second brain’. So if you’ve ever felt nervous before a presentation or had the sensation of butterflies in your stomach before going on a date, now you know why.

But did you know the relationship goes further than these surface feelings?

About 95% of the ‘happy hormone’ serotonin is made in the gut

How can gut health impact mental health?

So, why is gut health important for mental health? And how does it make an impact? Let’s look at the science.

The interconnectedness of gut health and mental health is clear when we look at the ‘happy hormone’ serotonin – about 95% of total body serotonin is made in the gut. A study linking irritable bowel syndrome (IBS) and a lack of serotonin production further highlights how the enteric and central nervous systems may impact each other.

In addition, mental health conditions have been found to be more prominent in people with functional gastrointestinal disorders (FGID). In one study, most of the people who were experiencing gut problems also had mental health disorders, which in turn affected gut health. So it’s a two-way street.

Finally, inflammation and other imbalances in the gut might impact how messages travel through the vagus nerve, which connects the brain and the gastrointestinal tract.  

It’s been found mental health conditions are more prominent in people with gut problems

Does poor gut health equal poor mental health?

We know that good gut health is more likely achieved when there’s a healthy balance of good bacteria in our gastrointestinal systems. A healthy gut supports normal nervous system function and may lead to other mental and physical benefits. 

Alternatively, someone with poor gut health or an imbalance in their gut microbiome – also known as dysbiosis – might experience the opposite.

One study looked at the link between gut dysbiosis and mood disorders and how the diversity of gut bacteria was different in the people experiencing the two conditions. The study also found that gut microbiota can influence brain function through the nervous system, neuroimmune and neuroendocrine pathways. So while more research is needed, the evidence points to poor gut health as a potential factor in poor mental health.

Due to the complexities of mood disorders and mental wellbeing, it’s important not to think of gut health and mental health links as the only answer. However, working towards a healthier gut may be beneficial.

Can a healthier gut improve mental health?

With a growing body of research looking at gut bacteria and mental health, there are suggestions that improving gut health might be used as a treatment one day. Specifically, it may involve mental health interventions that involve gut microbiota. However, as a relatively new area of research, more studies are needed for definitive answers.

A 12-week randomised controlled trial called SMILES looked at the possible impact of diet on mental health disorders, with promising results.

Can probiotics help your gut?

Probiotics supplements are often marketed toward improving gut health, without any mention of mental health. However, a meta-analysis of various clinical trials found that probiotics had a small but significant effect on patients with mood disorders, so it’s an exciting area for further research.

It’s worth noting that focusing on eating a healthier gut-friendly diet should be your first consideration. If you choose to take probiotics, remember that we each have trillions of bacterial cells in our body – so everyone’s microbiome is unique.

“We know that there are many different strains of probiotics, and it's not as simple as just taking a probiotic concoction that fixes you,” says Accredited Practising Dietitian Kate Agnew. “It’s important to talk to your healthcare professional to understand which probiotic strains show evidence for improving mood and which one is right for your gut health and mental health.”

Kate suggests other strategies that might improve gut health. “Work at getting the basics right,” she says. “Look at fibre intake, adequate sleep, exercise and stress management as equally important as trying a new probiotic.” 

You could also consider options like L-glutamine or bone broth that may help to support gut health.

How gut health impacts mental health is an area of science that is showing great potential for the future

Gut health and mental health: an important alliance

It’s exciting times for those interested in new frontiers in medical research that explore the relationship between gut health and mental health. The potential in this space is huge, so stay tuned for future developments. 

Consult your healthcare professional if you’re concerned about your gut health. Likewise, Beyond Blue can offer mental health support for those in need.

Related:

• Could the gut-brain axis be a link to better health? 
• What can you do to support your gut health?
• What you need to know about how probiotics work

Kate Agnew is an Accredited Practising Dietitian who is passionate about innovation and problem-solving in health & nutrition. Her goal is to ultimately create a healthier environment for all Australians.

Reviewed by healthylife health experts February 2023.