One-carbon metabolism-related compounds are associated with epigenetic aging biomarkers: results from the cross-sectional National Health and Nutrition Examination Survey 1999-2002

BACKGROUND: One-carbon metabolism (OCM), a biochemical pathway dependent on micronutrients including B vitamins, plays an essential role in aging-related physiological processes. DNA methylation-based aging biomarkers may be influenced by OCM. OBJECTIVES: This study investigated associations of OCM-related biomarkers with epigenetic aging biomarkers in the cross-sectional National Health and Nutrition Examination Survey (1999-2002). METHODS: Blood DNA methylation was measured in adults aged ≥50 y. The following epigenetic aging biomarkers were included: Horvath1, Horvath2, Hannum, PhenoAge, GrimAge2, Dunedin Pace-of-Aging (DunedinPoAm), and DNA methylation telomere length (DNAmTL). We tested for associations of serum folate, red blood cell folate, vitamin B12, homocysteine (Hcy), and methylmalonic acid (MMA) concentrations with epigenetic age deviation (EAD) among 2346 participants with epigenetic and nutritional status biomarkers using adjusted survey-weighted general linear regression models. RESULTS: A doubling of serum folate concentration was associated with -0.82 y (95% confidence interval: -1.40, -0.23) lower GrimAge2 EAD, -0.13 SDs (-0.22, -0.03) lower DunedinPoAm, and 0.02 kb (0.00, 0.04) greater DNAmTL EAD. Conversely, a doubling in Hcy concentration was associated with 1.05 y (0.06, 2.04) greater PhenoAge EAD, 1.93 y (1.16, 2.71) greater GrimAge2 EAD, and 0.26 SDs (0.10, 0.41) greater DunedinPoAm. Associations of serum folate with EAD were attenuated after adjusting for smoking status, alcohol intake, and estimated glomerular filtration rate. Furthermore, smoking modified the associations of Hcy with GrimAge2 EAD. Chronic kidney disease modified associations of B12 and MMA with Horvath1 and GrimAge2 EAD, respectively. CONCLUSIONS: In a nationally representative sample of United States adults, higher concentration of folate, a carbon donor, was associated with lower EAD, and higher concentration of Hcys, an indicator of OCM deficiencies, was associated with greater EAD; however, some associations were influenced by smoking and renal function. Future research should focus on high-risk populations. Long-term randomized controlled trials are also needed to establish causality and investigate the clinical relevance of changes in EAD.