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Overview
In a recent study in the International Journal of Cancer  ,1 men with higher dietary intake of vitamin C were found to be at reduced risk of developing oral premalignant lesions (OPLs). This study finding was featured in online news articles from Reuters Health , 2 the Canadian Broadcast Corporation 3 and other agencies.
The newly published study evaluated the association between dietary and supplemental intake of vitamins C, E, A and carotenoids (e.g., alpha-carotene, beta-carotene, lycopene) and the incidence of leukoplakia (white patches) and other OPLs. For this prospective evaluation, over 42,000 male health professionals provided information on dietary and supplemental nutrient intake every two to four years through food frequency questionnaires. The data collection was performed as part of the Health Professional Follow-Up Study, an ongoing evaluation of health factors that may be related to cancer and other diseases. All study participants were between the ages of 40 and 75 years at the study’s inception in 1986.
Over the study period (from 1986 to 2002), 207 oral premalignant lesions were identified in the male subjects. The study reported that there was not a significant association between OPL risk and total intake (both dietary and supplemental sources) of vitamins C, E, A or carotenoids. However, after adjusting for tobacco use, age, alcohol consumption and other potential confounders, the authors concluded that increased consumption of vitamin C from dietary sources alone, but not supplements, was associated with reduced OPL risk.
Previous research has identified potential associations between dietary and nutritional factors and oral cancer risk. While studies have shown that nutritional deficiencies can produce changes in the oral cavity, the available evidence supporting the effectiveness of dietary supplements in reducing risks of various types of cancer is generally inconclusive. As explained in the new prospective study, “vitamin C has well-established antioxidant properties, [but] it is possible that the protection seemingly offered by its dietary intake is actually partly due to some other component of vitamin C-rich foods.” Overall, the new study suggests a possible association between high dietary intake of vitamin C and reduced OPL risk, but does not establish a definitive cause-effect relationship.
In a separate analysis of current tobacco users, the authors found that smokers with the highest intake of dietary beta-carotene or vitamin E had nearly twice the OPL risk than those in the lowest intake category. Based on this finding, the authors recommended further research “to consider possible detrimental effects of certain isolated supplements,” particularly in smokers.
Although the study has several design limitations (e.g., the uncertain premalignant potential of lichen planus, and drawing data solely from self-reported dietary intake), it offers a long-term epidemiological evaluation of dietary and supplemental intake and OPL risk in large cohort of American men. Importantly, 16 to 40 percent of oral premalignant lesions transform to cancer, and the annual incidence rate for oral cancer is twice as high in men than in women . Further, the available evidence commonly links a high percentage of oral cancer cases with tobacco smoking and alcohol use.
Early detection of OPLs is essential to improving oral cancer survival. Tobacco-use cessation is a primary goal in preventing or lowering risks of oral cancer and other primary diseases. To support oral cancer prevention and improved oral health, dentists are encouraged to take an active role in oral cancer screening, promoting tobacco cessation, and encouraging patients to maintain a healthy, balanced diet.
Footnotes
1Maserejian NN, Giovannucci E, Rosner B, Joshipura K. Prospective study of vitamins C, E and A and carotenoids and risk of oral premalignant lesions in men. Int J Cancer. 2007 Mar 1;120(5):970-7. Abstract available at: "http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=
pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=17163413&query_hl=5&itool=
pubmed_docsum ."
2Rizzo M. Dietary vitamin C may prevent oral pre-cancer. Reuters Health, March 16, 2007. Available at: “http://www.nlm.nih.gov/medlineplus/news/fullstory_46674.html ”.
Accessed March 20, 2007.
3Vitamin C from diet linked to lower oral cancer risk. Canadian Broadcast Corporation, March 19, 2007. Available at: "http://www.cbc.ca/health/story/2007/03/19/oral-cancer.html
?ref=rss
“.
Accessed March 22, 2007.
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Science in the News is a service by the American Dental Association (ADA) to present current information about science topics in the news. The ADA is a professional association of dentists committed to the public's oral health, ethics, science and professional advancement; leading a unified profession through initiatives in advocacy, education, research and the development of standards. As a science-based organization, the ADA's evaluation of the scientific evidence may change as more information becomes available. Your thoughts would be greatly appreciated.
Page Posted March 2007
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