Ah, the gut microbiome: everything seems to come back to it, from immune health to mood. This complex ecosystem hiding out of plain sight beneath our bellies seems to play a part in everything. Scientific journals are booming with more insights into the gut microbiome and just how important keeping this part of ourselves is to our health. If you’re taking probiotics or prebiotics or want to promote a calm mood, you’ll want to take note of this recent study.
Researchers from the University of Surrey tested how prebiotics can impact mental health, specifically to relieve feelings of uneasiness. There are many probiotics marketed today for mood which contain bacteria that are known to reduce feelings of worry, but the effects of prebiotics are lesser known.
Prebiotics are basically food for the good bacteria in the intestinal system. By providing the type of food on which these good bacteria thrive, the population of good bacteria will outnumber the harmful bacteria. Prebiotics are non-digestible substances found in foods, such as fibers, bananas, garlic, onions, leeks, and others.
In this study of 64 healthy adult females, a prebiotic called galacto-oli-gosaccharides (one of the favorite foods of the beneficial bacteria Bifidobacterium) was administered for 28 days. The participants had urine cortisol tests to measure stress, and surveys about their mood and wellbeing. After 4 weeks of the prebiotic supplement, self-reported anxious patients reported less symptoms, consistent with earlier analysis into probiotics which were found to change brain signals in the areas of emotional regulation.
Most of the previous studies focused on middle-aged adults, and this was a successful investigation into inducing positive changes in young adults, aged 18 to 25 years old. Prebiotics are generally thought to be less disruptive to the balance of gut bacteria already in place, since they provide the type of food that only benefits the good bacterial populations.
How can tiny bacteria have such an impact on mental health? The gut bacteria create short-chain fatty acids through fermentation which can directly influence GABA and glutamate activity and the excitatory/inhibitory balance within the gut-brain axis. People seeking a more balanced mood may be able to find success with the gentler prebiotics and should discuss this with their healthcare practitioners.
Nicola Johnstone, Chiara Milesi, Olivia Burn, et al. Anxiolytic effects of a galacto-oligosaccharides prebiotic in healthy females (18–25 years) with corresponding changes in gut bacterial composition. Scientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-87865-w