How Your Gut Talks To Your Brain: The Food - Mood Connection

World Mental Health Day • Friday, 10 October 2025

We all know that what we eat affects our energy and physical health - but did you know your gut could also influence how you feel?

This World Mental Health Day, we’re shining a light on the fascinating link between your gut and brain - known as the gut–brain axis - and how simple food choices can support both a happy gut and a healthier mind.

What Is the Gut–Brain Axis (and Why Does It Matter)?

Your gut and brain are in constant conversation. This two-way chat happens through nerves (especially the vagus nerve), hormones, and even the trillions of bacteria living in your digestive system - your gut microbiome.

When your gut microbes are healthy and balanced, they help produce compounds that support good mood, focus, and calm - like serotonin and short-chain fatty acids (1,2). But when your gut is out of balance, it can lead to inflammation and stress signals that may affect your mood and mental wellbeing (3).

In other words: a happy gut really can mean a happier you.

The Science -  “Food and Mood: Current Evidence on Mental Health and the Microbiota-Gut-Brain Axis”

A recent review published in Current Psychiatry Reports pulled together global research on how diet and gut health can influence mental wellbeing (4).
Here’s what scientists found:

• Diets rich in fibre, whole grains, and fermented foods can positively impact mood and stress levels (4,5).
• The gut microbiome helps regulate brain chemicals like serotonin and dopamine (6).
• Supporting gut health through food is a safe, natural, and effective way to complement other mental health strategies (7).

It’s early days, but the science is exciting — and it suggests what we eat may be just as important for our mind as it is for our body. Want to know more? Read the full review on PubMed.

What Australian Research Is Saying

Australia is leading the way in this space, with world-class teams exploring how diet and gut health affect mental wellbeing:

• The Food & Mood Centre (Deakin University) - led by Professor Felice Jacka, this pioneering group found that people who eat more whole foods and fibre tend to have better mental health outcomes (8).
• Monash University’s Diet, Gut & Brain Group - studying how different diets influence the gut microbiome and mood, including the role of prebiotics and probiotics (9).
• University of Melbourne’s Bugs & Brains Study - exploring how the balance of gut bacteria may relate to anxiety and depression in Australians (10).

Simple Ways to Feed Your Gut - and Support Your Mind

You don’t need to overhaul your diet overnight. Even small changes can help create a gut environment that supports mental wellbeing:

1. Eat more fibre every day – Whole grains, fruits, veggies, legumes, and BARLEYMAX® are great for your gut microbes (11).
2. Try fermented foods – Think yoghurt, kefir, kimchi, or sauerkraut for natural probiotics (12).
3. Mix it up – Aim for 30+ plant foods a week to feed a diverse range of gut bacteria (13).
4. Cut back on ultra-processed foods – They can disrupt the gut–brain balance (14).
5. Stay hydrated and move daily – Both help keep your gut (and mood) flowing smoothly (15).

This World Mental Health Day…

Take a moment to check in - not just with your mind, but with your gut too.
They’re on the same team, working together to support your mood, focus, and overall wellbeing.

References

1. Mayer EA, Tillisch K, Gupta A. Gut/brain axis and the microbiota. J Clin Invest. 2015;125(3):926–938.
2. Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci. 2012;13(10):701–712.
3. Rieder R, Wisniewski PJ, Alderman BL, Campbell SC. Microbes and mental health: A review. Brain Behav Immun. 2017;66:9–17.
4. Simpson CA, Walker AJ, Reyes A, Bravo JA. Food and Mood: Current Evidence on Mental Health and the Microbiota–Gut–Brain Axis. Curr Psychiatry Rep. 2025. PMID: 41026445.
5. O’Neil A, et al. Relationship between diet and mental health in children and adolescents: a systematic review. Am J Public Health. 2014;104(10):e31–e42.
6. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Res. 2018;1693(Pt B):128–133.
7. Dash S, Clarke G, Berk M, Jacka FN. The gut microbiome and diet in psychiatry: focus on depression. Curr Opin Psychiatry. 2015;28(1):1–6.
8. Jacka FN, et al. Association of Western and traditional diets with depression and anxiety in women. Am J Psychiatry. 2010;167(3):305–311.
9. Staudacher HM, et al. The diet–microbiota–brain axis: Implications for diet in IBS and beyond. Nutrients. 2021;13(11):4074.
10. Loughman A, et al. The Bugs and Brains Study: The role of the gut microbiome in mental health. BMJ Open. 2021;11(3):e043221.
11. Makki K, Deehan EC, Walter J, Bäckhed F. The impact of dietary fiber on gut microbiota in host health and disease. Cell Host Microbe. 2018;23(6):705–715.
12. Sarkar A, et al. Psychobiotics and the manipulation of bacteria–gut–brain signals. Trends Neurosci. 2016;39(11):763–781.
13. Ruengsomwong S, et al. The more diverse, the better? Diet diversity and gut microbiota composition. Nutrients. 2022;14(4):795.
14. Lane MM, et al. Ultra-processed food and mental health: cross-sectional and longitudinal associations. Public Health Nutr. 2023;26(2):333–343.
15. Allen AP, et al. Exercise and the gut microbiota: implications for mood and wellbeing. J Psychiatr Res. 2017;94:1–8.