First results from the Fiberdia study
/Beneficial effects on gut microbiota after six weeks of prebiotic fiber supplements in patients with type 2 diabetes.
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 the Fiberdia study is to investigate whether a prebiotic fibre supplement may improve glycaemic regulation in type 2 diabetes by imposing changes in the gut microbiota that subsequently increase GLP-1 secretion and satiety.
The study is 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 six weeks in randomised order, with a 4-week washout inbetween the treatments. The faecal microbiota was analysed by high-throughput 16S rRNA amplicon sequencing and short chain fatty acids (SCFA) in faeces were analysed using vacuum distillation followed by gas chromatography. SCFA are products of bacterial fermentation of fibre. Besides being important sources of energy for the colonocytes and substrates for gluconeogenesis and lipogenesis in the liver, the SCFAs are also important signalling molecules involved in the regulation of blood glucose and appetite.
In this first publication from the study we have shown that treatment with inulin-type fructans induced moderate changes in the faecal microbiota composition (1.5%, p = 0.045). A bifidogenic effect was most prominent, with highest positive effect on operational taxonomic units (OTUs) of Bifidobacterium adolescentis, followed by OTUs of Bacteroides. The prebiotic fibres had no effects on the overall microbial diversity. Significantly higher faecal concentrations of SCFA, in particulare acetic acid and propionic acid, were also detected after prebiotic consumption compared to placebo. Our findings suggest a moderate potential of inulin-type fructans to improve gut microbiota composition and to increase microbial fermentation in type 2 diabetes.
The next two articles from the Fiberdia study will present the effect of the prebiotic fibres on GLP-1 and -2, appetite regulating hormones, as well as effects on blood glucose, insulin, and subjective sensation of appetite.
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