HALIFAX, CANADA. Several studies have concluded that high homocysteine levels are associated with coronary artery disease (CAD). It is believed that homocysteine promotes atherosclerosis through increased oxidative stress and by "encouraging" dysfunction of the lining of the arteries (endothelial dysfunction). It is generally accepted that folic acid supplementation will lower homocysteine levels, but whether folic acid supplementation will also reduce the endothelial dysfunction responsible for the initiation and progression of atherosclerosis is less certain.
Medical researchers at the Queen Elizabeth II Health Sciences Centre now report
that supplementation with 5 mg/day of folic acid significantly decreases
endothelial dysfunction. The extent of endothelial dysfunction is determined by
measuring the blood flow through the brachial artery in the arm (flow-mediated
dilation or FMD). The clinical trial included 75 patients with CAD. The
patients were randomized into three groups. One group took 5 mg of folic acid
daily for four months; the second group took 5 mg of folic acid plus 2000 mg of
vitamin C plus 800 IU of vitamin E per day; the third group was given a placebo.
At the end of the trial patients in the folic acid group had increased their
blood plasma level of folate by 475 per cent (from 14 nmol/L to 80 nmol/L) and
decreased their homocysteine level by about 11 per cent. FMD improved
significantly as well (from 3.2 to 5.2 per cent). Patients in the folic acid
plus antioxidant group increased their folate level by 438 per cent, reduced
homocysteine by 9 per cent, and improved FMD from 2.6 to 4.0 per cent.
The researchers point out that the FMD improvement seen in the folic acid
supplemented groups is similar to that seen with statin drugs and ACE
inhibitors. They conclude that four months of folic acid supplementation is
safe and significantly reduces endothelial dysfunction in patients with
established coronary atherosclerosis. [61 references]