Effects of supplementation with folic acid and antioxidant vitamins on homocysteine levels and LDL oxidation in coronary patients

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 α-tocopherol, 150 mg ascorbic acid, 12.5 mg β-carotene, and 0.4 μg 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 α-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 μmol/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, α-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.