Gut microbiome composition is linked to Mediterranean diet adherence and blood glucose control in adults with type 1 diabetes

Abstract

Microbiome composition has been related to blood glucose control in children with type 1 diabetes (T1D). The Mediterranean Diet (MD) influences microbiome composition in healthy people. Whether MD influences blood glucose control in adults with long-lasting T1D through microbiome modification is not known. We aim in this study to investigate the relationships between MD, blood glucose control, and gut microbiome composition in adults with T1D, also exploring the feasibility of using gut microbiome profiles as predictive markers for clinical parameters and dietary patterns. In a cross-sectional study of 253 individuals with T1D, diet was assessed by EPIC questionnaire, adherence to the MD was evaluated by relative Mediterranean diet score (rMED), gut microbiome was analyzed by shotgun metagenomics and glucose control was assessed by HbA1c and continuous glucose monitoring. High adherence to MD was linked to improved blood glucose control, as evidenced by significantly lower HbA1c levels compared to subjects with low adherence. High adherence to MD was significantly associated with enrichment in beneficial microbial species. Conversely, low adherence corresponded to higher levels of potentially harmful species. Microbiome significantly predicted several variables including HbA1c and MD adherence. Our results highlight the beneficial effects of MD adherence on blood glucose control and gut microbiome composition in adults with long-standing T1D. The study was registered at ClinicalTrials.gov with the identifier NCT05936242.