Your mental health plays a significant role in your overall health. There are many ways you can look after your mental health. This can include having a strong social network of friends and family, including meditation in your routine, exercise, and self-care practices like enjoying a warm bubble bath. One way you can support the health of your mind which you may not have considered is your gut health. Specifically, how a healthy gut microbiome may help promote mental wellbeing.
You have around ten trillion microbes living in your gut which send signals out into your body influencing its function, this includes your brain. Microbes can use the vagus nerve which is a direct link of communication from your gut to your brain. Microbes may also send signals indirectly using the enteric nervous system with a division off the main central nervous system to then send signals onto the vagus nervous system.
Ninety percent of the hormone called serotonin is produced in your gut. This ‘feel good hormone’ influences your mood and mental health. Your gut also produces around fifty percent of the dopamine in your body which influences your brain’s ability to make decisions and control your thoughts. If your gut is not made up of healthy microbes these can influence the type and amounts of different hormones present in your body. Consequently, it influences your mental health and brain function.
The health promoting microbes in your gut need to be fed to stay alive and well. These come from plant-based foods such as wholegrains, nuts, seeds, legumes, beans, fruits and vegetables. These foods provide prebiotic fibre which are a type of fibre that are a fuel for the health promoting microbes. A healthy lifestyle strategy can be to include thirty different plant foods a week. Each plant-based food provides distinct types of prebiotic fibre and supports the health of different health promoting microbes.
For a healthy gut microbiome, it is also important to include probiotic foods and beverages. The FAO/WHO definition of a probiotic is to be 'live microorganisms which when administered in adequate amounts confer a health benefit on the host’. These can include probiotic rich yoghurt, kimchi, miso, tempeh, and sauerkraut, to name a few.
A recent Australian study investigated the effects of a high prebiotic diet and probiotic supplements on mental health. One hundred and nineteen adults were selected for this study. The adults selected were all diagnosed with moderate levels of psychological stress. It was a randomized trial where the adults were randomly selected to take one of four choices for eight weeks duration. These choices were consuming a normal diet for that person with no probiotic supplement, taking a probiotic supplement only while eating a normal diet for that individual. The third choice was eating a diet which contained high prebiotic fibre only without probiotics and the final option was a diet which was high in prebiotic fibre and included a probiotic supplement.
Researchers used a self-reported measure of psychological disturbance called Total Mood Disturbance. There were five categories of mood disturbance in this measure. The higher the total mood disturbance score the more distress the participant was experiencing. Researchers also investigated the effects of these eating styles on levels of anxiety, depression, stress, sleep, and wellbeing measures.
After eight weeks, the researchers found that the diet which was high in prebiotic fibre was the only group of the four which resulted in moderate improvements in the total mood disturbance score. The probiotic only group and the probiotic and prebiotic group both showed mild improvements in the total mood disturbance score. Researchers also concluded that a diet high in prebiotic fibre may improve components of mental health including mood, anxiety, stress, and sleep.
Take home message: Your mental health matters. There are many ways you can help look after your mental health. One major contributor to your mental health is your gut health. Eating a diet which includes a variety of prebiotic and probiotic sources could play a key role in promoting optimal mental health and wellbeing.
References:
- Hill, C., Guarner, F., Reid, G. et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506–514 (2014). https://doi.org/10.1038/nrgastro.2014.66
- Freijy TM, Cribb L, Oliver G, Metri NJ, Opie RS, Jacka FN, Hawrelak JA, Rucklidge JJ, Ng CH, Sarris J. Effects of a high-prebiotic diet versus probiotic supplements versus synbiotics on adult mental health: The "Gut Feelings" randomised controlled trial. Front Neurosci. 2023 Feb 6;16:1097278. doi: 10.3389/fnins.2022.1097278. PMID: 36815026; PMCID: PMC9940791.
