Effects of a diverse prebiotic fibre blend on inflammation, the gut microbiota, and affective symptoms: A pilot open label randomised controlled trial

Emerging evidence suggests that low-grade systemic inflammation plays a key role in altering brain activity, behaviour, and affect. Modulation of the gut microbiota using prebiotic fibre offers a potential therapeutic tool to regulate inflammation, mediated via the production of short-chain fatty acids (SCFAs). However, the impact of prebiotic consumption on affective symptoms, and the possible contribution from inflammation, gut symptoms, and the gut microbiome, is currently underexamined. In this 12-week study, the effects of a diverse prebiotic blend on inflammation, gut microbiota profiles, and affective symptoms in a population with Metabolic Syndrome (MetS) was examined. Sixty patients meeting the criteria for MetS were randomised into a treatment group (n = 40), receiving 10g per day of a diverse prebiotic blend and healthy eating advice and a control group (n = 20), receiving healthy eating advice only. Our results showed a significant reduction in C-reactive protein (CRP), alongside improvements in self-reported affective scores in the treatment compared to the control group. While there were no differences in relative abundance between groups at week 12, there was a significant increase from baseline to week 12 in Bifidobacterium and Parabacteroides in the treatment group, both of which are recognised as SCFA producers. Multivariate regression analyses further revealed that changes in affective scores were positively associated with both gastrointestinal symptoms and CRP. Together, this study provides preliminary support for the use of a diverse prebiotic blend for mood, stress, and anxiety.