Adherence to the dietary index for gut microbiota is associated with lower cardiometabolic dysregulation in type 2 diabetes

Dietary patterns that support gut microbiota may influence interconnected cardiometabolic pathways. We investigated the association between adherence to a gut microbiota-supportive dietary pattern, assessed by the Dietary Index for Gut Microbiota (DI-GM), and multisystem cardiometabolic dysregulation in adults with type 2 diabetes (T2D). In this cross-sectional study, 385 adults with T2D from diabetes clinics in Zanjan, Iran were included. Dietary intake was assessed using a validated 168-item food frequency questionnaire, and DI-GM scores (0-14) were derived from 14 microbiota-related components. A composite cardiometabolic dysregulation score was calculated from standardized markers of glycemic control, lipid profile, inflammation, liver enzymes, and blood pressure. Multivariable linear regression was used to estimate associations across DI-GM quartiles and per 1-SD increase, adjusting for demographic, lifestyle, and clinical factors. Dose-response relationships were assessed using restricted cubic splines. Higher DI-GM adherence was inversely associated with cardiometabolic dysregulation. In fully adjusted models, participants in the highest quartile had significantly lower dysregulation scores than those in the lowest (β = -0.31; 95% CI: -0.42, - 0.20; P-trend < 0.001). Each 1-SD increase in DI-GM was associated with a - 0.17 reduction (95% CI: -0.24, - 0.10). Associations were linear with no evidence of non-linearity and remained robust after further adjustments. In adults with T2D, higher adherence to a microbiota-oriented dietary pattern, assessed using the DI-GM, was associated with lower multisystem cardiometabolic dysregulation. Given the cross-sectional design, these findings should be interpreted as observational associations and do not establish temporality or causality. Longitudinal and prospective studies, preferably with direct gut microbiome assessment, are needed to confirm these findings and clarify whether DI-GM adherence is temporally or causally related to cardiometabolic dysregulation.