Long-term improvement in homocysteine levels and arterial endothelial function after 1-year folic acid supplementation

Purpose Hyperhomocysteinemia, a risk factor for atherosclerosis, is associated with endothelial dysfunction that can be improved with short-term folic acid supplementation. The current study aimed to assess whether folic acid supplementation could produce longer-term improvements in homocysteine levels and arterial endothelial function. Subjects and methods Twenty-nine healthy adults with hyperhomocysteinemia were selected from 89 volunteers enrolled in a community-based atherosclerosis screening project. All subjects were given folic acid (10 mg/d) for 1 year. Fasting plasma homocysteine levels were measured by high-performance liquid chromatography. Arterial endothelial function was measured as flow-mediated dilation of the brachial artery using high-resolution B-mode ultrasound. Results Folic acid supplementation for 1 year was associated with a significant increase in mean (±SD) plasma folate levels (24 ± 5 nmol/L to 40 ± 5 nmol/L; P<0.001) and a significant decline in homocysteine levels (9.0 ± 1.7 μmol/L to 7.9 ± 2.0 μmol/L; P<0.001). Flow-mediated dilation also improved significantly, from 7.4% ± 2.0% to 8.9% ± 1.5% (P<0.0001), but there was no change in nitroglycerin-induced (endothelium-independent) responses. Conclusion These results demonstrate that long-term folic acid improves arterial endothelial function and has potential implications for the prevention of atherosclerosis in adults with hyperhomocysteinemia.