April 9, 2001 -- A glass of orange juice is a popular breakfast drink, and for most of us it also supplies needed vitamin C. But for people who have a disease that affects circulation to the legs and feet, called peripheral arterial disease or PAD, a glass of orange juice or even a vitamin C supplement may not be enough.
Michel Langlois, MD, PhD, a researcher from Belgium who has been studying PAD, tells WebMD that even if people with the disease consume a healthy amount of vitamin C, blood tests still indicate low levels of the vitamin.
So is the answer another glass of OJ or few vitamin C capsules? No so fast, says Langlois. He says that more studies are needed before any recommendations about vitamin C and PAD can be issued. Based on the research he has already completed, which is published in the April 10 issue of Circulation, Journal of the American Heart Association, Langlois says "we cannot conclude that increasing vitamin C intake would increase [blood] levels of vitamin C."
Additional studies may be able to nail down what is depleting vitamin C in people with PAD. Langlois says that although vitamin C levels bottom out among patients with PAD, these same people have high levels of what's called C-reactive protein or CRP, which is an indicator for inflammation.
He says this combination in people with PAD -- low levels of vitamin C and high levels of CRP -- may be explained by understanding the underlying disease.
People with PAD have painful and disabling cramps in their legs when they walk, he says. The condition is actually a type of atherosclerosis, or hardening of the arteries, the same disease that causes heart attacks and stroke, he says. In fact, people with PAD are more likely to die of a heart attack or stroke than are people whose arterial disease doesn't affect the legs.
In atherosclerosis, arteries and other blood vessels are lined with fat deposits and buildup of cellular materials, including inflammatory cells, which release unstable molecules called free radicals. The free radicals do additional damage to the delicate vessels, says Langlois. Antioxidants such as vitamin C seek out and destroy free radicals, but in the process the antioxidants are themselves destroyed.
The bottom line, says Langlois, is that PAD appears to kick the body's inflammatory process into high gear, which then releases a free radical bombardment, that can "deplete the supply of vitamin C."
Langlois, who is a specialist in clinical pathology at the Hospital of Ghent in Belgium, discovered the association between PAD and vitamin C when he tested 85 people with PAD, 106 people who had high blood pressure but no circulation problems in their legs, and 113 healthy volunteers.
People in each group consumed an average of 120 mg of vitamin C daily, he says. But the blood levels of vitamin C "did not correlate with dietary intake in the PAD group," he says. In the other two groups, the blood levels "correlated with dietary intake." Moreover, the other groups had no evidence of elevated CRP, but the PAD group did.
So turning the concept around, does this research mean that increasing the intake of vitamin C could actually help people suffering from PAD, or even atherosclerosis in general? Not necessarily, says Ronald M. Krauss, MD, who chairs the American Heart Association's council on nutrition, physical activity, and metabolism. "We are still lacking clear evidence that vitamin C supplementation can actually treat atherosclerosis," he tells WebMD. But, he says the study by Langlois does add some needed information to the ongoing vitamin C debate.
For example, Krauss says that earlier studies demonstrated that smoking depletes the levels of vitamin C in the blood. In the new study, Langlois "demonstrated that the low level of vitamin C in people with PAD appears to be independent of smoking. That is an important observation because it suggests that something about the condition [PAD] itself is associated with loss of vitamin C."
Krauss says that such observations help researchers understand the mechanism of disease, but don't add much to current treatment approaches.
Although Americans are very intrigued by the possibility that they could take a vitamin to cure or prevent heart disease, Krauss says that is probably just wishful thinking. Though taking "a modest dose of vitamin C, say 500 mg a day, is generally safe, I don't think that something so powerful as atherosclerosis is going to be overcome by one or another simple vitamin supplement."
A better approach, says Krauss, is to follow a diet high in fruits, vegetables, and grains and low in fat and to exercise regularly.