Serum and Dietary Folate and Vitamin B(12) Levels Account for Differences in Cellular Aging: Evidence Based on Telomere Findings in 5581 U.S. Adults

Folate and vitamin B(12) are essential for a variety of metabolic processes. Both micronutrients have been shown to reduce oxidative stress significantly. The present cross-sectional investigation evaluated the association between serum and dietary folate and vitamin B(12) levels and leukocyte telomere length, an index of cellular aging influenced by oxidative stress. The study included 5581 adults from the National Health and Nutrition Examination Survey (NHANES). Because participants were randomly selected, results are generalizable to all civilian, noninstitutionalized U.S. adults. A blood draw provided DNA and serum folate and B(12) information. The quantitative polymerase chain reaction method was used to measure telomere length. The Bio-Rad Quantaphase II folate and vitamin B(12) radioassay kit was used to quantify levels of folate and vitamin B(12). Dietary folate and vitamin B(12) were assessed using a multipass 24 h recall. In some models, age, race, smoking pack-years, alcohol use, body mass index, total physical activity, hours fasted before the blood draw, and diabetes status were employed as covariates to minimize their influence. Findings showed that for each additional year of chronological age, telomeres were 15.6 base pairs shorter, on average (F = 378.8, p < 0.0001). Men had shorter telomeres than women after adjusting for all the covariates (F = 6.8, p = 0.0146). Serum (F = 10.5, p = 0.0030) and dietary (F = 5.0, p = 0.0325) folate concentrations were each linearly related to telomere length in women, but not in men, after controlling for age and race. Serum vitamin B(12) and telomere length had a nonsignificant, inverse relationship in women, with age and race controlled (F = 2.8, p = 0.1056), but no relation in men. Dietary vitamin B(12) was linearly related to telomere length in women, after adjusting for age and race (F = 4.3, p = 0.0468), but not in men. Overall, evidence indicates that folate and vitamin B(12) levels, especially folate, account for meaningful differences in cell aging in women, but not in men.