Dose-dependent effects of folic acid on blood concentrations of homocysteine: A meta-analysis of the randomized trials

420Citations
Citations of this article
212Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Background: Dietary supplementation with B vitamins that lower blood homocy steine concentrations is expected to reduce cardiovascular disease risk, but there has been uncertainty about the optimum regimen to use for this purpose. Objective: The objectives were to ascertain the lowest dose of folic acid associated with the maximum reduction in homocysteine concentrations and to determine the additional relevance of vitamins B-12 and B-6. Design: A meta-analysis of 25 randomized controlled trials involving individual data on 2596 subjects assessed the effect on plasma homocysteine concentrations of different doses of folic acid and of the addition of vitamins B-12 and B-6. Results: The proportional reductions in plasma homocysteine concentrations produced by folic acid were greater at higher homocysteine (P < 0.001) and lower folate (P < 0.001) pretreatment concentrations; they were also greater in women than in men (P < 0.001). After standardization for sex and to pretreatment plasma concentrations of 12 μmol homocysteine/L and 12 nmol folate/L, daily doses of 0.2, 0.4, 0.8, 2.0, and 5.0 mg folic acid were associated with reductions in homocysteine of 13% (95% CI: 10%, 16%), 20% (17%, 22%), 23% (21%, 26%), 23% (20%, 26%), and 25% (22%, 28%), respectively. Vitamin B-12 (x̄: 0.4 mg/d) produced 7% (95% CI: 4%, 9%) further reduction in homocysteine concentrations, but vitamin B-6 had no significant effect. Conclusions: Daily doses of ≥0.8 mg folic acid are typically required to achieve the maximal reduction in plasma homocysteine concentrations produced by folic acid supplementation. Doses of 0.2 and 0.4 mg are associated with 60% and 90%, respectively, of this maximal effect. © 2005 American Society for Clinical Nutrition.

Cite

CITATION STYLE

APA

Clarke, R., Frost, C., Sherliker, P., Lewington, S., Collins, R., Brattstrom, L., … Law, M. (2005). Dose-dependent effects of folic acid on blood concentrations of homocysteine: A meta-analysis of the randomized trials. American Journal of Clinical Nutrition, 82(4), 806–812. https://doi.org/10.1093/ajcn/82.4.806

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free