Reduction of homocysteine levels in coronary artery disease by low-dose folic acid combined with vitamins B6 and B12

An increased plasma homocysteine concentration is a risk factor for atherosclerosis. Folic acid lowers homocysteine but the optimal dose in patients with coronary artery disease (CAD) is unclear. This placebo-controlled, single-blind, dose-ranging study evaluates the effect of low-dose folic acid on homocysteine levels in 95 patients aged 61 +/- 11 years (mean +/- SD) with documented CAD. Patients in each group were given either placebo or 1 of 3 daily supplements of folic acid (400 mu g, 1 mg, or 5 mg) for 3 months. Each active treatment arm also received 500 mu g vitamin B-12 and 12.5 mg vitamin Bg. Total plasma homocysteine levels were measured after 30 and 90 days. Folic acid 400 mu g reduced homocysteine levels from 13.8 +/- 8.8 to 9.6 +/- 2.0 mu mol/L at 90 days (p = 0.001). On 1- and 5-mg folic acid, levels decreased from 13.0 +/- 6.4 to 9.8 +/- 4.0 mu mol/L (p = 0.001) and from 14.8 +/- 8.9 to 9.7 +/- 3.3 mu mol/L (p <0.001), respectively. The decrease was similar in all treatment groups. There was no significant change with placebo. Although the sample size is small, these findings suggest that daily administration of 400 mu g/day folic acid combined with vitamin B-12 and vitamin B-6 may be equivalent to higher doses in reducing homocysteine levels in patients with CAD. (C) 1999 by Excerpta Medica, Inc.