Dietary carbohydrate quality is associated with epigenetic age acceleration: a cross-sectional study of the CARDIA cohort.

Background: Dietary intake is one lifestyle factor that is expected to impact gene expression by altering DNA methylation (DNAm), thus affecting epigenetic aging. Studies on the association between quality of carbohydrates and epigenetic age acceleration (EAA) are scarce despite the evidence that quality may be more important than amount of carbohydrates consumed.

Objective: We aimed to identify the cross-sectional associations of carbohydrate quality and fiber-rich food score with epigenetic age acceleration in the Coronary Artery Risk Development in Young Adults (CARDIA) study.

Methods: Trained interviewers administered the CARDIA Diet History to obtain dietary intake at exam year 20. EAA measures, PhenoAge acceleration (PhenoAA) and GrimAge acceleration (GrimAA), were generated based on epigenetic age estimates calculated using DNAm profiling data from fasting blood samples at exam years 20, 25, and 30. Linear mixed effects regression models were used to evaluate the association of carbohydrate quality, defined using carbohydrate:fiber ratio, and fiber-rich food score with EAA measures.

Results: After adjusting for demographic and lifestyle factors, quartiles of carbohydrate quality (defined using carbohydrate:fiber ratio) were inversely associated with PhenoAA and GrimAA; the highest carbohydrate quality quartile showing a difference (SE) of -1.19 (0.2) years of PhenoAA (p-trend<0.001) and -1.20 (0.1) years of GrimAA (p-trend<0.001) compared with the lowest carbohydrate quality quartile. Similarly, quartiles of fiber-rich food score (created based on daily intakes of whole grains, fruit, vegetables, nuts, and legumes) were inversely associated with PhenoAA and GrimAA; the highest quartile showing a difference (SE) of -1.06 (0.2) years of PhenoAA (p-trend=0.002) and -1.31 (0.2) years of GrimAA (p-trend<0.001) compared with the lowest quartile.

Conclusions: Our study findings suggest that consuming a high carbohydrate quality diet and a dietary pattern composed of fiber-rich foods is cross-sectionally associated with slower biological aging.