Endothelial function in post-menopausal women: effect of folic acid supplementation

Abstract

Higher than normal homocysteine levels are associated with an increased incidence of adverse cardiovascular events in post-menopausal women, perhaps via hyperhomocysteinaemia-induced vascular endothelial damage. Because folic acid supplementation reduces homocysteine levels, we attempted to evaluate whether folic acid supplementation may affect endothelial function in post-menopausal women. Brachial artery flow-mediated dilatation (endothelium-dependent) and nitroglycerin-induced dilatation (endothelium-independent) before and after a methionine load were analysed in 15 healthy post-menopausal women. Plasma levels of folate, homocysteine, glucose, insulin and lipids were measured, as was blood pressure. All studies were repeated after 1 month supplementation with 7.5 mg/day of folic acid. After folate, endothelial function rose 37% over pre-folic acid supplementation value (P < 0.001), and flow-mediated dilation before folic acid was reduced by 62% subsequent to methionine loading (P < 0.0001); this reduction was still present after folic acid, but was only 19% (P < 0.001). Nitroglycerin-induced dilatation did not change in response to methionine loading before or after folic acid supplementation. Among the other cardiovascular risk factors studied, only high-density lipoprotein (HDL)-cholesterol and low-density lipoprotein (LDL)-cholesterol showed significant changes after folic acid supplementation, with a 6% increase (P < 0.03) and a 9% decrease (P < 0.03) respectively. Although preliminary, these results indicate that folic acid supplementation may improve endothelial function and lipid profile in post-menopausal women, thus contributing to reduce their cardiovascular risk.