Use of folic acid supplements appears to lower blood levels of the amino acid homocysteinetheorized to be a risk factor for heart and blood vessel diseasebut does not appear to be associated with reduced rates of cardiovascular events, cancer or death over a five-year period, according to a meta-analysis of previously published studies in the October 11 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
"Elevated plasma total homocysteine [an amino acid created by the body, usually as a byproduct of eating meat] has been suggested as a potentially modifiable risk factor for coronary heart disease, stroke and other occlusive vascular conditions," the authors write as background information in the article. High rates of cardiovascular disease in children with homocystinuriaa rare genetic condition causing extreme elevations in homocysteine levelsled researchers to hypothesize that moderate increases in blood homocysteine levels may increase cardiovascular disease risk in the general population.
Supplementation with B vitamins, and in particular folic acid, lowers blood homocysteine levels and reduces cardiovascular disease risk among individuals with homocystinuria. Several large clinical trials conducted in patients without the condition have been inconclusive. "Consequently, a collaboration between their investigators was established in 2004 to conduct a meta-analysis based on individual participant data from all large randomized trials of folic acidbased B-vitamin supplementation intended to lower plasma homocysteine levels for the prevention of cardiovascular disease," the authors write.
Robert Clarke, F.R.C.P., University of Oxford, England, and colleagues in the B-Vitamin Treatment Trialists' Collaboration report the results of the meta-analysis of all eight trials completed by the end of 2009. Of a total of 37,485 participants, 18,723 were assigned to take folic acid in doses ranging from 0.8 millig
|Contact: Robert Clarke, F.R.C.P.|
JAMA and Archives Journals