Oral folic acid improves endothelial dysfunction in cigarette smokers

Endothelial dysfunction is an early manifestation of the atheromatous process and is evident without overt clinical signs or symptoms of the disease. Cigarette smoking has been shown to be associated with endothelial dysfunction in otherwise healthy adults. Although cessation of smoking is the ideal objective, it is not always attainable, and therefore any strategy to prevent early endothelial dysfunction is desirable. Folic acid is currently under review as a rational therapeutic agent in hyperhomocysteinemia. However, folic acid may modify endothelial function independent of its effect on homocysteine. We therefore investigated the effect of folic acid on endothelial function in young otherwise healthy cigarette smokers.

Volunteer cigarette smokers (n = 10) and control lifelong nonsmokers were enrolled in the study. Baseline folate, vitamin B12, homocysteine, and cholesterol levels were analyzed. Flow-mediated dilatation, an endothelial-dependent phenomenon, was assessed using ultrasonography. This scan was performed at baseline and following 4 weeks of folic acid supplementation (5 mg/day).

There were no significant differences in the baseline hematological investigations between the groups. Homocysteine levels were within normal limits in both groups and did not change following folic acid supplementation. Cigarette smokers demonstrated significant endothelial dysfunction compared to controls (P < 0.005). This difference was significantly attenuated by folic acid supplementation (P < 0.005).

Folic acid significantly improves endothelial function in otherwise healthy cigarette smokers. This provides a potential therapeutic tool in attenuating the atheromatous process in this group.