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.
"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
SOURCE: International Journal of Cancer, March