Effects of Vitamin D ₃ supplementation on epigenetic aging in overweight and obese african americans with suboptimal Vitamin D status: A randomized clinical trial

Background We have previously shown that vitamin D supplementation increases telomerase activity, suggesting an anti-aging effect. In this study, we aim to test the hypothesis that vitamin D supplementation would slow down epigenetic aging, a new marker of biological aging. Methods A randomized clinical trial was previously conducted among 70 overweight/obese African Americans with serum 25-hydroxyvitamin D [25(OH)D] < 50 nmol/L, who were randomly assigned into four groups of 600 IU/d, 2,000 IU/d, 4,000 IU/d of vitamin D 3 supplements or placebo followed by 16-week interventions. Whole genome-wide DNA methylation analysis was conducted in 51 participants. DNA methylation ages were calculated according to the Horvath and the Hannum methods. Methylation-based age acceleration index (ΔAge) is defined as the difference between DNA methylation age and chronological age in years. Mixed-effects models were used to evaluate the treatment effects. Results Fifty-one participants (aged 26.1 ± 9.3 years, 16% are male) were included in the study. After the adjustment of multi-covariates, vitamin D 3 supplementation of 4,000 IU/d was associated with 1.85 years decrease in Horvath epigenetic aging compared with placebo (p value =.046), and 2,000 IU/d was associated with 1.90 years decrease in Hannum epigenetic aging (p value =.044). Serum 25(OH)D concentrations were significantly associated with decreased Horvath ΔAge only (p values =.002), regardless of treatments. Conclusions Our results suggest that vitamin D supplementation may slow down Horvath epigenetic aging. But the effect on Hannum epigenetic aging is not conclusive. Large-scale and longer duration clinical trials are needed to replicate the findings.