Development of dietary methyl score using plasma homocysteine level in the large two US cohort study

Abstract

BackgroundsOne‐carbon metabolism, crucial in DNA synthesis and genomic stability, is a metabolic pathway where nutrients are networked interdependently. The development of comprehensive score integrating the interconnected nutrients within the pathway is necessary.MethodsA total of 3,283 participants with measured plasma total homocysteine (tHCY) levels in the Nurses’ Health Study and the Health Professionals Follow‐up Study were randomly divided into the training (n=2,626) and the testing subset (n=657). Dietary methyl score predicting plasma tHCY were derived with the known one carbon metabolism related nutrients (alcohol, folate, vitamin B2, vitamin B12, vitamin B6, vitamin B12, betaine, choline, and methionine) in the training set using the multivariate linear regression. The correlation of the dietary methyl score with plasma tHCY levels was assessed in the testing set.ResultsThe known one‐carbon nutrients explained 29% of the variation of plasma tHCY in the multivariate prediction model (model r2 = .29).Vitamin B2 were the strongest predictor, followed by folate, alcohol, betaine, vitamin B6, and methionine (P<.05). Intake of choline, and vitamin B12 were non‐significant and were taken out from the score calculation. Our dietary methyl score derived from the coefficient of the multivariate prediction model was positively correlated with the plasma tHCY in the testing set (Pearson correlation r=0.28, P = <.001; plasma tHCY range= 10–14 umol/L comparing extreme deciles of the dietary methyl score).ConclusionsDietary methyl score predicted plasma tHCY level significantly. The complexity in the one‐carbon metabolism may be better reflected in the dietary methyl score.