WEDNESDAY, Feb. 15, 2006 (HealthDay News) -- Vitamin C supplements can help halt the serious depletion of vitamin E in smokers and possibly help prevent cancer, U.S. researchers report.
The study led by investigators at Oregon State University is the first to demonstrate this type of interaction between the two antioxidants in humans. They researchers say the findings also suggest a possible mechanism by which smoking causes cancer.
Reporting in the Feb. 15 issue of Free Radical Biology and Medicine, the study researchers found that giving smokers 1,000 milligrams per day of vitamin C could reduce by up to 45 percent the rate of disappearance of one form of vitamin E. Vitamin C supplements also helped protect the function and plasma levels of vitamin E, the study authors found. Smokers who took vitamin C supplements had nearly the same amount of antioxidant protection as non-smokers.
Vitamin E is one of the lungs' first lines of defense against cigarette smoke, which creates destructive free radicals. Adequate levels of vitamin E can help prevent destruction of lung membranes. But, through this protective process, vitamin E itself can become a destructive radical, the scientists said.
This study found that sufficient levels of vitamin C help vitamin E return to non-radical form and continue to protect the lungs.
"What this clearly shows is that to perform their vital roles, vitamins C and E work together," Maret Traber, professor of nutrition, said in a prepared statement. "They have a synergistic effect that will not be gained just by intake of one or the other, and adequate levels of these nutrients is especially important for people who smoke."
"A lot of nutrition research in the past has been done by studying one nutrient or another in isolation, sometimes with conflicting results," Traber noted.
"What this and other studies like it are showing is that the protection we get from proper diet or supplements often comes from combinations of nutrients working together. This has implications not only for smokers but also for many other people."
The findings come on the heels of a study published Tuesday in the Journal of the National Cancer Institute that found that vitamin E supplements appeared to cut the risk of prostate cancer for men who smoke -- but not for non-smokers.
More information
The U.S. National Library of Medicine has more about vitamins.
