Meta-Analysis: Folic Acid Supplementation Prevents Stroke

Cardiovascular disease is the number one cause of death in the United States and other developed countries. High levels of plasma homocysteine are a significant independent risk factor for cardiovascular disease, including stroke. A recent meta-analysis analyzed eight folic acid supplementation studies, with a total of 16,841 participants, and found a significant decrease in risk for stroke with folic acid supplementation. This is the first meta-analysis of the effect of folic acid supplementation on primary prevention of stroke. The researchers stated the effect was slow in developing, with the best results after 36 months of supplementation. Cardiovascular disease is a slow, lifelong process, so it makes sense that any improvement in the disease progress would take some time. Overall, folic acid reduced the risk of stroke 18 percent. The effect was best in people who lowered their homocysteine level more than 20 percent, with a relative risk in these individuals of 0.77 (p=0.012), which equals a 23-percent reduced risk.

Wang X, Qin X, Demirtas H, et al. Efficacy of folic acid supplementation in stroke prevention: a meta-analysis. Lancet 2007;369:1876-1882.