Dietary intake and epigenetic aging in an African population: food groups, dietary patterns, and plant-based diets in the RODAM study.

BACKGROUND: Epigenetic age acceleration (EAA) is a biological marker of healthy longevity. While diet–EAA associations are documented in high-income countries, data from low- and middle-income populations—where diets can differ substantially—are unavailable. We examined associations between three complementary dietary components (specific food groups, dietary patterns, and plant-based food proportions) and EAA among Ghanaians across the nutrition transition (rural Ghana, urban Ghana, the Netherlands). METHODS: We analyzed cross-sectional data from 705 adults in the RODAM study (2019–2021). Dietary intake was assessed via a Ghana-adapted Food Frequency Questionnaire (30 food groups; PCA-derived dietary patterns; Satija plant-based diet approach). EAA was estimated using DNA methylation clocks (Horvath, Hannum, PhenoAge, GrimAge) from Illumina EPIC array data. Linear regression models were used adjusted for demographic, lifestyle, health factors, and immune cell composition. Mediation analyses assessed potential biological pathways. RESULTS: In rural Ghana, fish intake was associated with lower Horvath EAA (β= -0.028) and PhenoAge EAA (β= -0.026). In urban Ghana, fermented maize intake was inversely associated with Hannum EAA (β= -0.002) and PhenoAge EAA (β= -0.006). In Amsterdam, condiment intake was positively associated with Hannum EAA (β = 0.010) and PhenoAge EAA (β = 0.012). Dietary patterns and plant-based proportions were not associated with EAA. Dietary vitamins D, B9 and B12 partially mediated associations (11 to 49%). CONCLUSIONS: Among Ghanaians, intake of specific food groups (fish, fermented maize, condiments) were associated with EAA in specific contexts. Dietary patterns and plant-based food proportions did not show associations with EAA. Given the cross-sectional design, causal inference is not possible; longitudinal studies in these settings are warranted.