Folic acid, widely touted as a heart-healthy supplement, neither increases nor decreases the risk of cardiovascular events or all-cause mortality in patients with a history of cardiovascular disease (CVD) or end-stage renal disease (ESRD), according to just-published data.
Researchers at Tulane University in New Orleans analyzed 12 randomized controlled trials that included nearly 17,000 patients with pre-existing vascular disease. All of the trials compared folic-acid supplements with placebo or usual care for at least six months. Though all the trials showed that supplements lowered blood homocysteine levels—by -1.5 to -26 µmol/L—there was no statistically significant relationship between reduced homocysteine levels and any specific clinical outcome.
The overall relative risk of adverse events for patients treated with folic acid compared with controls was 0.95 for CVD; 1.04 for coronary heart disease; 0.86 for stroke; and 0.96 for all-cause mortality. The results were similar for patients with pre-existing CVD or renal disease.
Although the researchers say their findings suggest that folic acid is ineffective in the secondary prevention of CVD, they leave open the possibility that it may have a protective effect in primary prevention (JAMA. 2006;296:2720-2726).