Medical doctors at Ghent University Hospital reasoned that patients with intermittent claudication might have low levels of vitamin C (ascorbic acid), a primary defense against oxidative stress. Intermittent claudication is a cramping pain induced by exercise (walking) and relieved by rest. It is caused by an inadequate supply of blood to the affected muscles and is most often a result of atherosclerosis. There is now considerable evidence that atherosclerosis is caused by a continual low-grade inflammation and the resulting oxidative stress. Their study involved 85 patients with peripheral arterial disease (PAD), the cause of intermittent claudication, 106 patients with high blood pressure, but no PAD and 113 age-matched healthy subjects. The analysis of fasting blood samples from all the participants showed that PAD patients had low serum vitamin C concentrations. Fifty-two per cent had concentrations below the lower reference limit of 28.4 micromol/L and 14 per cent had a clinical vitamin C deficiency. Vitamin C levels were normal in the healthy subjects and in the patients with hypertension. The researchers noted that smokers had vitamin C levels that were about 40 per cent lower than those found in non-smokers. They conclude that the vitamin C deficiency found in PAD patients is due to their increased level of oxidative stress (low-grade inflammation). They point out that a recent clinical trial found that antioxidant supplementation may prevent cardiovascular events in PAD patients, but does not improve walking distance.
Langlois, Michel, et al. Serum vitamin C concentration is low in peripheral arterial disease and is associated with inflammation and severity of atherosclerosis. Circulation, Vol. 103, April 10, 2001, pp. 1863-68