Gut microbiota of Type 1 diabetes patients with good glycaemic control and high physical fitness is similar to people without diabetes: an observational study

Aim - Type 1 diabetes is the product of a complex interplay between genetic susceptibility and exposure to environmental factors. Existing bacterial profiling studies focus on people who are most at risk at the time of diagnosis; there are limited data on the gut microbiota of people with long-standing Type 1 diabetes. This study compared the gut microbiota of patients with Type 1 diabetes and good glycaemic control and high levels of physical-fitness with that of matched controls without diabetes. Methods - Ten males with Type 1 diabetes and ten matched controls without diabetes were recruited; groups were matched for gender, age, BMI, peak oxygen uptake (VO2max), and exercise habits. Stool samples were analysed using next-generation sequencing of the 16S rRNA gene to obtain bacterial profiles from each individual. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) was implemented to predict the functional content of the bacterial operational taxonomic units. Results - Faecalibacterium sp., Roseburia sp. and Bacteroides sp. were typically the most abundant members of the community in both patients with Type 1 diabetes and controls, and were present in every sample in the cohort. Each bacterial profile was relatively individual and no significant difference was reported between the bacterial profiles or the Shannon diversity indices of Type 1 diabetes compared with controls. The functional profiles were more conserved and the Type 1 diabetes group were comparable with the control group. Conclusions - We show that both gut microbiota and resulting functional bacterial profiles from patients with long-standing Type 1 diabetes in good glycaemic control and high physical fitness levels are comparable with those of matched people without diabetes.