Fecal Microbiota and Metabolites Predict Metabolic Health Features across Various Dietary Patterns in Adults.

Background: Consuming healthful dietary patterns reduces risk of developing metabolic diseases and nourishes the intestinal microbiota. Thus, investigating the microbial underpinnings of dietary influences on metabolic health is of clinical interest.

Objectives: This study aims to determine the unique contributions of fecal taxa and metabolites in predicting metabolic health markers in adults across various dietary patterns.

Methods: Dietary, metabolic, and fecal microbiota and metabolome data from 118 adults (25-45 y) were used for these cross-sectional analyses. The Diet History Questionnaire II assessed adherence to the dietary approaches to stop hypertension (DASH), Mediterranean diet, Mediterranean-DASH intervention for neurocognitive delay (MIND), and the Healthy Eating Index-2020 (HEI-2020). Metabolic features included waist circumference, blood pressure, and circulating triglyceride (TG), high-density lipoprotein cholesterol, and glucose concentrations. Microbiota composition was assessed via 16S amplicon sequencing and volatile fatty acid and bile acid concentrations were measured by targeted metabolomics. Analyses of compositions with bias correction 2 and correlation analyses were used to screen for microbiota features independently associated with dietary patterns and metabolic health markers. Then, hierarchical linear regression models were used to evaluate the unique contributions of select microbial features on metabolic markers beyond adherence to dietary patterns.

Results: HEI-2020 positively associated with microbiota richness (P = 0.02). Beta diversity varied across all dietary patterns (P < 0.05). DASH diet scores, (Eubacterium) xylanophilum abundance, and deoxycholic acid concentration explained the most variance in systolic (R² = 0.32) and diastolic (R² = 0.26) blood pressure compared with other dietary patterns and microbial features. TG concentrations were best predicted by MIND diet scores, (E.) eligens abundance, and isobutyrate concentrations (R² = 0.24).

Conclusions: Integrating fecal taxa and metabolites alongside dietary indices improved metabolic health marker prediction. These results point to a potential role of the intestinal microbiota in underpinning physiological responses to diet and highlight potential microbial biomarkers of metabolic health.