EFFECT OF B-GROUP VITAMINS AND ANTIOXIDANT VITAMINS ON HYPERHOMOCYSTEINEMIA - A DOUBLE-BLIND, RANDOMIZED, FACTORIAL-DESIGN, CONTROLLED TRIAL

Mild hyperhomocysteinemia is accepted as a risk factor for premature c ardiovascular disease. In a population with a high prevalence of cardi ovascular disease, we screened a group of clinically healthy working m en aged 30-49 y (n = 509) for plasma homocysteine and 5,10-methylene t etrahydrofolate reductase (MTHFR) genotype status. Those with mildly e levated homocysteine concentrations (greater than or equal to 8.34 mu mol/L) were selected for intervention. In a randomized, factorial-desi gn. controlled trial we assessed the effects of B-group vitamins and a ntioxidant vitamin supplementation on homocysteine concentrations. The 132 men were randomly assigned to one of four groups: supplementation with B-group vitamins alone (1 mg folic acid, 7.2 mg pyridoxine, and 0.02 mg cyanocobalamin), antioxidant vitamins alone (150 mg ascorbic a cid, 67 mg RRR-alpha-tocopherol, and 9 mg beta-carotene), B-group vita mins with antioxidant vitamins, or placebo. Intervention was double-bl ind. A total of 101 men completed the 8-wk intervention. When homocyst eine concentrations were analyzed by group, significant (P < 0.001) de creases (32.0% and 30.0%, respectively) were observed in both groups r eceiving B-group vitamins either with or without antioxidants. The eff ect of B-group vitamins alone over 8 wk was a reduction in homocystein e concentrations of 27.9% (95% CI: 22.0%, 33.3%: P < 0.001) whereas an tioxidants alone produced a nonsignificant increase of 5.1% (95% CI: - 2.8%, 13.6%; P = 0.21). There was no evidence of any interaction betwe en the two groups of vitamins. The effect of B-group vitamin supplemen tation seemed to depend on MTHFR genotype. Supple mentation with the B -group vitamins with or without antioxidants reduced homocysteine in t he men with mildly elevated concentrations, and hence may be effective in reducing cardiovascular risk.