The effect of oral folic acid upon plasma homocysteine, endothelial function and oxidative stress in type 1 diabetes with microalbuminuria

Aims: The purpose of this study was to investigate the effect of oral folic acid supplementation upon plasma homocysteine (HCY), endothelial function and oxidative stress on patients with type 1 diabetes and microalbuminuria to test the hypothesis that oral folic acid would lower plasma HCY and thereby improve endothelial function and reduce oxidant stress in this high-risk group of patients. Methods: We measured plasma HCY, forearm blood flow, total antioxidant status and whole blood glutathione at baseline and after 2 months treatment with oral folic acid or placebo in 16 patients with type 1 diabetes and microalbuminuria. Results: Plasma HCY fell by 25% in the folic acid group but there was no difference in endothelial function or markers of oxidant stress in the treatment group. Conclusions: Oral folic acid supplementation successfully lowered plasma HCY levels in patients with type 1 diabetes and microalbuminuria, however this was not associated with improvements in endothelial function or markers of oxidant stress.