Associations of various healthy dietary patterns with biological age acceleration and the mediating role of gut microbiota: results from the China Multi-Ethnic Cohort study.

To investigate the associations between dietary patterns and biological aging, identify the most recommended dietary pattern for coping with biological aging and explore the potential mediating role of gut microbiota in less-developed ethnic minority regions (LEMRs). This prospective cohort study included 8288 participants aged 30-79 years from the China Multi-Ethnic Cohort study (CMEC). Anthropometric measurements and clinical biomarkers were utilized to construct biological age based on Klemera and Doubal's method (KDM-BA) and KDM-BA acceleration (KDM-AA). Dietary information was obtained through the baseline food frequency questionnaire (FFQ). Six dietary patterns were constructed: plant-based diet index (PDI), healthful plant-based diet index (hPDI), unhealthful plant-based diet index (uPDI), healthy diet score (HDS), Dietary Approaches to Stop Hypertension (DASH), and alternative Mediterranean diets (aMED). Follow-up adjusted for baseline analysis were employed to assess the associations between dietary patterns and KDM-AA. Additionally, quantile G-computation was utilized to evaluate the significant beneficial and harmful food groups. In the subsample of 764 participants with gut microbiota data obtained through 16S rRNA gene sequencing, we used causal mediation model to explore the mediating role of gut microbiota in the associations between dietary patterns and KDM-AA. The results showed that all dietary patterns were associated with KDM-AA. Transitioning from non-compliance to compliance, DASH exhibited the strongest negative association with KDM-AA [β = -0.91, 95%CI (-1.19, -0.63)]. The component analyses revealed that tea and soybean products were the significant beneficial food groups, while salt, preserved vegetables, red and processed meats were identified as the major harmful food groups. In mediation analysis, the decreased abundance of Synergistetes phylum and Pyramidobacter genus possibly mediated the negative associations between plant-based diets and KDM-AA (5.61%-9.19%). Overall, healthy dietary patterns, especially DASH, are negatively associated with biological aging in LEMRs. The Synergistetes and Pyramidobacter may mediate the associations between plant-based diets and biological aging. Developing appropriate strategies may promote healthy aging in LEMRs.