The association between dietary quality and biological aging: two-mediation analysis

Previous research has emphasized the firm link between diet and human health. However, the connection between comprehensive dietary patterns and biological aging has not been fully investigated. Our aim was to explore the potential association between dietary quality and delaying aging.

A total of 20,763 participants from the National Health and Nutrition Examination Survey were included in this cross-sectional study. The Mediterranean diet score (MDS), dietary approaches to stop hypertension index (DASHI), and healthy eating index 2020 (HEI2020) were utilized to assess dietary quality. Biological age was determined using the Klemera-Doubal method (KDM) biological age and phenotypic age (Levine's), with the difference between biological age and chronological age representing aging acceleration. Independent relationships between dietary quality and biological aging were analyzed using weighted adjusted linear and logistic regression. Nonlinear trends and robustness of conclusions were examined. A secondary objective was to examine the role of Klotho and γ-glutamyltransferase (GGT) in mediation analyses.

Dietary quality exhibited a negative association with biological aging, as evidenced by the interplay between three dietary patterns and two aging measures (The β of the linear regressions were all < 0). Restricted cubic splines confirmed the linear relationship, while subgroup interactions bolstered the stability of the results. Mediation analysis indicated that klotho and GGT partially mediated the association between dietary quality and biological aging (combined proportion mediation: 4.1-8.0%).

Dietary quality is closely associated with biological aging, with anti-aging proteins and oxidative stress potentially serving as underlying mediation mechanisms.