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Can Food Lift Your Mood? What the Gut Feelings Trial Found
By Dr Hazel Batten, Integrative GP at Remede Wellness Medicine
In an Australian trial, adding everyday foods that feed your gut bacteria eased low mood, stress and poor sleep.
Here is what the researchers did, what they found, and what it might mean for you.
The gut and the brain are closely connected, and interest in how we can support that connection keeps growing. The Gut Feelings trial looked at two ways to do it: probiotic supplements, and the food on your plate.
What Did the Study Do?
The Gut Feelings trial, led by researchers at the University of Melbourne and published in 2023, was the first randomised controlled trial to compare a diet rich in prebiotics with probiotic supplements for mental health.
Researchers recruited 119 adults with moderate psychological distress who ate few prebiotic foods. For eight weeks, each person was placed in one of four groups:
- Probiotic: a daily multistrain probiotic capsule
- Prebiotic diet: at least seven serves a day of prebiotic foods, plus a placebo capsule
- Synbiotic: the prebiotic diet and the probiotic together
- Placebo: a placebo capsule with their usual diet
Prebiotics are the fibres our beneficial gut bacteria feed on. The diet groups added foods such as onion, garlic, asparagus, oats, whole wheat, chickpeas and watermelon, introduced gradually over a few days to limit bloating and wind.
What Did They Find?
The prebiotic diet stood out. Compared with placebo, people eating more prebiotic foods had a moderate improvement in overall mood, along with less anxiety, lower stress and better sleep.
The probiotic group showed an improvement in general wellbeing. Interestingly,combining the diet with the probiotic did not add extra benefit in this trial. The researchers suggest the added bacteria and the body’s own microbes may have been sharing the same fibre, though a small study like this can also throw up chance results.
Probiotics still have an important place in gut care, and the right choice depends on the person and their goals. This trial tested one product over eight weeks, and its clearest message is that food is the foundation everything else builds on.
Why Might Food Help Mood?
When gut bacteria ferment prebiotic fibre, they make short chain fatty acids such as butyrate. These compounds help maintain the gut lining and calm inflammation, and they may influence the brain through the gut brain axis, including how we respond to stress.
Whole foods also bring more than prebiotics. People in the diet groups ate more plants overall, so some of the benefit may come from better diet quality in general. That is a good reminder that food works as a whole pattern, not as a single ingredient
The Caveats
This is promising, early evidence rather than a final answer. A few things are worthknowing:
- It was small.
- Each group had around 30 people, so the results need confirming in larger trials.
- People knew what they were eating.
- Unlike the capsules, the diet could not be hidden, which may have shaped how people rated their symptoms.
- The participants were a particular group. About nine in ten were women, most were university educated, and none had a diagnosed mental health condition.
- The benefit needed the habit. Twelve weeks after the trial ended, most people had drifted back to their old eating patterns, and the difference in mood was no longer clear.
Simple Ways to Add Prebiotic Foods
You do not need a complete overhaul. Small, steady additions are easier on the gut and easier to keep up:
- Start the day with oats. Porridge or overnight oats, topped with a slightly green banana or some fruit.
- Build meals on onion and garlic. Use them generously as the base of soups, curries, stirfries and sauces.
- Add a handful of legumes. Chickpeas, lentils or beans in salads, soups or a quick hummus.
- Choose wholegrain breads and pasta over refined versions where you can.
- Try leek, asparagus or Jerusalem artichoke when they are in season.
- Go slowly. Add one or two new serves every few days and drink plenty of water. Some extra wind is normal at first and usually settles.
If you live with IBS, follow a low FODMAP plan, or have another gut condition, many prebiotic foods can trigger symptoms. Please talk with your practitioner before makin gbig changes.
The Takeaway
This study is not a reason to stop any current treatment, including medication orsupplements you have been prescribed. Low mood, anxiety and poor sleep have many contributing factors, and food is one piece of the picture.
What it does offer is an encouraging, affordable and low risk place to start. Feeding your gut bacteria well, and keeping it up, may support your mood, stress levels and sleep.
If you would like help putting this into practice, Jane and the team at Remede can work with you on an eating plan that suits your gut, your health history and your lifestyle. And if low mood or anxiety is affecting your daily life, please book in with your GP.
Reference: Freijy TM et al. (2023). Effects of a high prebiotic diet versus probioticsupplements versus synbiotics on adult mental health: The “Gut Feelings” randomised controlled trial. Frontiers in Neuroscience, 16:1097278.
*This article is general information only and not a substitute for individual medical advice.*