Folic acid not effective for secondary prevention of CVD
Although folic acid reduces plasma homocysteine it does not reduce the risk of cardiovascular disease in patients with pre-existing vascular or renal disease.
A meta-analysis was carried out on 12 trials involving almost 17,000 patients with vascular or renal disease who received folic acid supplements, placebo or nothing for six months to five years.
Folic acid supplements, 0.5 to 15 mg/day, lowered plasma homocysteine by 1.5 to 26 µmol/l but failed to reduce the risk of CHD, cardiovascular disease, stroke or death. One in five patients suffered a cardiovascular event irrespective of whether they received folic acid and around 12 per cent died.
Bazzano LA, Reynolds K, Holder KN et al. Effect of folic acid supplementation on risk of cardiovascular diseases: a meta-analysis of randomized controlled trials JAMA 2006;296:2720-6