- Posted by jdavis on June 23, 2011
Increased intake of vitamin C from the diet, but not supplements, may slash the risk of mouth cancer by 48 per cent, says a epidemiological study.
According to British charity the Mouth Cancer Foundation, oral cancers have a higher proportion of deaths per number of cases than breast, skin, or cervical cancer, with a mortality rate of about 50 per cent due to late detection.
The new research, led by Nancy Nairi Maserejian from Harvard School of Public Health, suggests that increased intake of vitamin C from the diet may reduce the risk of developing the cancer by about 50 per cent.
The new study, published in the International Journal of Cancer, used data on supplement use and diet for 42,340 men in the Health Professionals Follow-up Study. Information obtained from food frequency questionnaires was updated every two to four years.
During the course of the study, 207 oral pre-malignant lesions (OPL) events were documented by Maserejian and her co-workers. After adjusting for various confounding factors, they found no significant risk reduction for total intake o vitamin C, vitamin A or carotenoids.
However, vitamin C from dietary sources was significantly associated with a reduced risk, but no association with the vitamin from supplements was found. Risk reductions were also found for the carotenoids, beta-cryptoxanthin and alpha-carotene, but no statistically significant changes in OPL were observed for beta-carotene, lycopene or lutein/zeaxanthin intakes.
An increase in the risk of oral cancer was observed with increasing vitamin E intake, said the researchers, particularly among smokers who were taking supplements, a result that should be explored further in additional studies.
“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 told 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.
The study does have several notable limitations, including relying on food frequency questionnaires to gather dietary information. FFQs are susceptible to recall of the subjects. It is also not known if cases adjusted their diet after diagnosis of their disease.
International Journal of Cancer
Volume 120, Issue 5, Pages 970 – 977