Changes of homocysteine levels and arterial endothelial function in patients with high risk of coronary artery disease after 6-month folic acid supplementation

OBJECTIVES: This study aimed to assess whether folic acid supplementation could produce longer-term (6-month) improvements in homocysteine levels and arterial endothelial function in patients with a high risk (3 or more traditional risk factors) of coronary artery disease (CAD) and hyperhomocysteinaemia. METHODS: Thirty-one adults with 3 or more traditional risk factors of CAD and hyperhomocysteinaemia were selected, without CAD (the criterion of CAD is that more than one main vessel has an obstruction > or = 50%) by coronary angiography. All subjects were given folic acid (5 mg/day) for 6 months. Fasting plasma homocysteine levels were measured by high-performance liquid chromatography. Plasma folic acid and vitamin B12 levels were measured with immunoassay. Arterial endothelial function was measured as flow-mediated dilation of the brachial artery using high-resolution B-mode ultrasound. RESULTS: Folic acid supplementation for 6 months was associated with a significant increase in mean (+/- SD) plasma levels of folic acid (4.6 +/- 1.4 microg/l to 9.1 +/- 2.5 microg/l; P < 0.01) and a significant decline in homocysteine levels (18.3 +/- 3.9 micromol/l to 11.5 +/- 2.8 micromol/l; P < 0.01). Flow-mediated dilation also improved significantly, from 6.8% +/- 2.1% to 8.9% +/- 1.7% (P < 0.01). CONCLUSION: These results demonstrate that long-term (6-month) folic acid administration significantly declines homocysteine levels and improves arterial endothelial function and has potential implications for the prevention of atherosclerosis in adults with 3 or more traditional risk factors of CAD and hyperhomocysteinaemia.