Hyperhomocysteinemia is an important cardiovascular risk factor. Serum 
homocysteine levels are specially dependent on folate nutritional status. In 
addition, the oxidative modification of low-density lipoproteins (LDLs) in the 
endothelial microenvironment is a damaging factor that can be modified with 
fat-soluble antioxidant vitamins. The present study was done to assess the 
effect of a supplementation of folic acid and antioxidant vitamins on 
homocysteine levels and in vitro LDL oxidation in patients with coronary artery 
disease. Twenty-three patients with angiographically proven coronary artery 
disease were given supplements for 15 d consisting of one capsule twice a day of 
a multivitamin preparation containing 0.65 mg folic acid, 150 mg 
alpha-tocopherol, 150 mg ascorbic acid, 12.5 mg beta-carotene, and 0.4 microgram 
vitamin B12. Serum lipids, vitamin and homocysteine levels, and in vitro LDL 
oxidation were measured before and after the supplementation period. During the 
supplementation period, serum folate levels increased from 5.0 +/- 1.5 to 10.8 
+/- 3.8 ng/mL (P < 0.001), vitamin B12 increased from 317.4 +/- 130.4 to 334.5 
+/- 123.8 pg/mL (P < 0.05), and alpha-tocopherol increased from 8.2 +/- 5.1 to 
13.7 +/- 7.9 mg/L (P < 0.001). Serum homocysteine levels decreased from 8.7 +/- 
4.3 to 6.3 +/- 2.2 mumol/L (P < 0.001). In vitro LDL oxidation decreased from 
2.6 +/- 1.1 to 1.6 +/- 1.1 nmol malondialdehyde/mg protein (P < 0.001). In 
comparing patients with healthy controls, basal levels of folate were lower in 
the patients, whereas vitamin B12, alpha-tocopherol, and homocysteine levels 
were similar. No changes in serum lipid levels or body weight were observed. In 
conclusion, a short-term supplementation with folic acid and antioxidant 
vitamins can reduce serum homocysteine levels and in vitro LDL oxidation in 
patients with coronary artery disease.