Prebiotic effect of inulin-type fructans on faecal microbiota and short-chain fatty acids in type 2 diabetes: a randomised controlled trial

Summary

Purpose Compared to a healthy population, the gut microbiota in type 2 diabetes presents with several unfavourable features that may impair glucose regulation. The aim of this study was to evaluate the prebiotic efect of inulin-type fructans on the faecal microbiota and short-chain fatty acids (SCFA) in patients with type 2 diabetes. Methods The study was a placebo controlled crossover study, where 25 patients (15 men) aged 41–71 years consumed 16 g of inulin-type fructans (a mixture of oligofructose and inulin) and 16-g placebo (maltodextrin) for 6 weeks in randomised order. A 4-week washout separated the 6 weeks treatments. The faecal microbiota was analysed by high-throughput 16S rRNA amplicon sequencing and SCFA in faeces were analysed using vacuum distillation followed by gas chromatography. Results Treatment with inulin-type fructans induced moderate changes in the faecal microbiota composition (1.5%, p=0.045). A bifdogenic efect was most prominent, with highest positive efect on operational taxonomic units (OTUs) of Bifdobacterium adolescentis, followed by OTUs of Bacteroides. Signifcantly higher faecal concentrations of total SCFA, acetic acid and propionic acid were detected after prebiotic consumption compared to placebo. The prebiotic fbre had no efects on the concentration of butyric acid or on the overall microbial diversity. Conclusion Six weeks supplementation with inulin-type fructans had a signifcant bifdogenic efect and induced increased concentrations of faecal SCFA, without changing faecal microbial diversity. Our fndings suggest a moderate potential of inulin-type fructans to improve gut microbiota composition and to increase microbial fermentation in type 2 diabetes. Trial registration The trial is registered at clinicaltrials.gov (NCT02569684).