NEW YORK (Reuters Health) Jul 15 - Findings from a large prospective study suggest that use of vitamin C supplements may protect against coronary heart disease (CHD).

Given the vitamin's antioxidant properties, it is plausible that high blood levels would protect the heart from injury, lead author Dr. Stavroula K. Osganian, from The Children's Hospital in Boston, and colleagues note. Still, previous studies examining the cardioprotective effects of vitamin C have yielded conflicting results. Most studies that have shown a benefit of vitamin C use have involved populations with low or deficient intake of the vitamin.

The new findings, published in the July 16th issue of the Journal of the American College of Cardiology, are based on data from the Nurses' Health Study in which 85,118 women completed food-frequency questionnaires and were followed for 16 years. During the study period, 1356 women developed CHD.

After adjusting for age, smoking status, and other heart disease risk factors, the researchers found that vitamin C intake was inversely related to CHD risk. Women who used vitamin C supplements were 28% less likely to develop CHD than were nonusers.

Among women who did not use supplements, dietary vitamin C intake was only weakly tied to CHD risk.

The results suggest that use of vitamin C supplements may protect against CHD, Dr. Osganian said in a statement. However, "our study cannot provide conclusive evidence for a protective role nor can it exclude the possibility that the association may be due to some other health-seeking characteristic among vitamin C supplement users," he added.

Randomized, placebo-controlled clinical trials are needed to prove that vitamin C is cardioprotective, Dr. Balz Frei, from Oregon State University in Corvallis, notes in a related editorial. However, such trials may be "prohibitively expensive and impractical" and "we may never know with certainty whether vitamin C supplementation is of benefit in the primary prevention of CHD."

"What we know with certainty, however, is that a healthy diet and lifestyle lowers the risk of CHD, and is what we should advocate to CHD patients and healthy people alike," Dr. Frei added.

J Am Coll Cardiol 2003;42:246-255.


http://www.medscape.com/viewarticle/458673?mpid=16083