Vitamins Lower Homocysteine Levels, Not Stroke Risk

WINSTON-SALEM, N.C.--High homocysteine levels have been linked with increased risk of many types of cardiovascular diseases, including coronary heart disease and high blood pressure. However, in a recent study, researchers found high and low doses of folic acid, vitamin B6 and vitamin B12 lower homocysteine levels in subjects but did not reduce stroke risk. The study was published in the Feb. 4 issue of the Journal of the American Medical Association (291, 5:565-75, 2004) (www.jama.ama-assn.org).

Approximately 3,600 adults who previously had a non-disabling stroke were involved in the 6.5-year Vitamin Intervention for Stroke Prevention (VISP) randomized controlled trial. Subjects received a daily multivitamin with low doses of folic acid (20 mcg), vitamin B6 (200 mcg) and vitamin B12 (6 mcg), or a daily multivitamin with high doses of the same vitamins (2.5 mg, 25 mg and .4 mg, respectively). Both the low- and high-dose multivitamins contained the recommended daily allowances of other vitamins.

Total homocysteine levels were lower in the high-dose group compared to the low-dose group; however, this had no effect on treatment outcome. The chance of having another stroke, a coronary heart disease event or succumbing to death within two years after treatment was 18 percent in the high-dose group compared to 18.6 percent in the low-dose group. In addition, the risk of ischemic stroke within two years of treatment was 9.2 percent for the high-dose group compared to 8.8 percent for the low-dose group. Researchers concluded the reduced homocysteine levels in subjects had no effect on vascular outcome two years after treatment; however, researchers did confirm the relationship between homocysteine levels and vascular risk.

This trial was supported by the National Institute of Neurological Disorders and Stroke. The raw materials for the vitamins were supplied by Roche Vitamins, which was acquired in December 2003 by DSM Nutritional Ingredients, based in Basel, Switzerland.