Dietary vitamin C may prevent oral pre-cancer

By Michelle Rizzo

NEW YORK (Reuters Health) - Vitamin C from dietary sources, but not from supplements, is associated with a reduced risk of oral pre-malignant lesions in men, a new study indicates.

Dr. Nancy Nairi Maserejian, of New England Research Institutes, Watertown, Massachusetts, and colleagues examined intake of vitamins C, E, A and carotenoids in 42,340 men enrolled in the Health Professionals Follow-up Study and the occurrence of oral pre-malignant lesions. The men provided information on supplement use and diet every 2 to 4 years.

A total of 207 oral premalignant lesions were diagnosed between 1986 and 2002, the team reports in the International Journal of Cancer.

The risk of developing such a lesion was not significantly linked to total intake of vitamin C, vitamin A, or carotenoids. However, dietary vitamin C was significantly associated with a reduced risk of oral premalignant lesions: those with the highest intake had a 50 percent reduction in risk compared to those with the lowest intake.

The researchers found no clear relationship with beta-carotene, lycopene, or lutein/zeaxanthin. A trend for increased risk of oral pre-malignant lesions was observed with vitamin E, especially among current smokers and with vitamin E supplements. Beta-carotene also increased the risk among current smokers.

"It is possible that the protection that seems to be offered by dietary intake of vitamin C is actually partly due to some other component of vitamin C-rich food," Maserejian said in an interview with Reuters Health.

"Although we do not yet know exactly what component -- or interaction between components -- is most important, a diet that includes vitamin C-rich foods as well as a variety of nutrients is likely to benefit most people," she said.

"Our results also highlight the need to consider possible harmful effects of high doses of vitamin E supplements among smokers," the researcher noted.

SOURCE: International Journal of Cancer, March 2007.