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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
medicine
Dose-dependent effects of folic acid on blood concentrations of homocysteine: A meta-analysis of the randomized trials
American Journal of Clinical Nutrition, Volume 82, No. 4, Year 2005
Notification
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Description
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.
Authors & Co-Authors
Clarke, Robert Joseph
United Kingdom, Oxford
Clinical Trial Service Unit and Epidemiological Studies Unit
Frost, Chris D.
Unknown Affiliation
Sherliker, Paul
Unknown Affiliation
Collins, Rory
Unknown Affiliation
Brattström, Lars E.
Unknown Affiliation
Brouwer, Ingeborg Annemarie
Unknown Affiliation
Steegers-Theunissen, Régine P.M.
Unknown Affiliation
Cuskelly, Geraldine J.
Unknown Affiliation
McNulty, Helene M.
Unknown Affiliation
Scott, John Martin
Unknown Affiliation
Den Heijer, Martin
Unknown Affiliation
Blom, Henk Johannes
Unknown Affiliation
Malinow, Manuel René
Unknown Affiliation
Joosten, Etienne
Unknown Affiliation
Riezler, Reiner
Unknown Affiliation
Pietrzik, Klaus F.
Unknown Affiliation
Dierkes, Jutta
Unknown Affiliation
Jacques, Paul F.
Unknown Affiliation
Mason, Joel B.
Unknown Affiliation
Rosenberg, Irwin H.
Unknown Affiliation
Thambyrajah, Jeetendra
Unknown Affiliation
Landray, Martin J.
Unknown Affiliation
Townend, Jonathan N.
Unknown Affiliation
Wheeler, David Collins
Unknown Affiliation
Ubbink, Johan Bernard
Unknown Affiliation
Melse-Boonstra, Alida
Unknown Affiliation
Woodside, Jayne V.
Unknown Affiliation
Yarnell, John W.G.
Unknown Affiliation
Young, Ian S.
Unknown Affiliation
Evans, Alun E.
Unknown Affiliation
Law, Malcolm R.
Unknown Affiliation
Statistics
Citations: 434
Authors: 31
Affiliations: 1
Identifiers
Doi:
10.1093/ajcn/82.4.806
ISSN:
00029165
Research Areas
Food Security
Noncommunicable Diseases
Study Approach
Systematic review
Participants Gender
Male
Female