Vitamin B9 supplements do not appear to reduce the risk of cardiovascular events, cancer or death, says a new U.K. review.
The meta-analysis included eight randomized controlled trials that measured rates of cardiovascular events, cancer and/or death of 37,485 participants receiving dietary supplements with 0.8 to 40 milligrams vitamin b9 (folic acid) per day or a placebo (respectively an equivalently small dose of folic acid) for a mean of five years. The analysis indicates that although folic acid supplementation was associated with a 25 percent reduction in homocysteine levels, there was no significant difference between folic acid and placebo groups in the number of participants experiencing major cardiovascular events, new cases of cancer or death. The researchers commented that their analysis at least reassured that a population-wide folic acid fortification, as used in the US to prevent neural tube birth defects, is safe.
Elevated blood levels of homocysteine are believed to be a potentially modifiable risk factor for coronary heart disease, stroke and other occlusive vascular conditions. It has been suggested that supplementation with B vitamins, and in particular folic acid, reduces cardiovascular disease risk by lowering elevated blood homocysteine levels. However, the results of several large clinical trials have been inconclusive.
Experts have criticized that the study does not consider that normal (folic acid supplementation lowered) homocysteine levels sustained in the long-term and in a preventative manner could benefit the heart and other systems in the body. In principle, folic acid and other supplements are not meant to be magic bullets and should not realistically be expected to cure heart disease or any other complex disease. However, when used properly, in combination with eating a healthy diet, getting routine exercise, and other healthy habits, folic acid supplements could play an important role in maintaining and promoting overall health.