Studies have shown a large, statistically significant reduction in the risk of cancers of the oral cavity and pharynx with high intake of fruits and vegetables (1).
This may be due to the potency of vitamins and minerals found in fruit and vegetable products, which aid the production of collagen, as well as the production of enzymes necessary for optimal metabolic function. In the absence of adequate vitamin and mineral intake, oxidative stress may lead to cellular changes that increase cancer risk.
Additionally, the antioxidant properties of certain vitamins and minerals work to inhibit the oxidative damage that sets the cellular change process in motion.
Vitamin C, a water-soluble vitamin found plentifully in bright-hued fruits and vegetables, has been of particular interest with regards to cancer prevention, including cancers of the oral cavity. Studies have shown a strong association between high Vitamin C intake and the prevention of oral cancer, but these findings have not translated to studies wherein Vitamin C was consumed in supplement form (2).
Vitamin C is found in abundant concentrations in broccoli, tomatoes, peppers, spinach, and other leafy greens.
Other studies have echoed the notion that vitamin and mineral-containing dietary supplements have not been shown to be nearly as beneficial as vitamins and minerals obtained from whole food sources (3).
This is likely because supplements are not currently regulated by the Food and Drug Administration, causing a reduction in product quality, or thanks to the symbiotic effect of whole food nutrition on digestion and absorption.
Vitamin A (also commonly referred to as beta-carotene) has shown a protective effect in animal models as well as epidemiological human studies (4,5). Vitamin A consumption is of particular debate with regards to tobacco consumers, as smokers present with depleted levels of Vitamin A.
However, studies wherein tobacco users supplemented with Vitamin A were ill-fated, with Vitamin A supplementation increasing risk for lung cancer (6).
Currently, the link between Vitamin A supplementation and increased cancer risk is not understood, especially given that smokers present with reduced Vitamin A status, which would theoretically be remedied by supplementation.
Vitamin A is found in large concentrations in green, leafy vegetables and yellow and orange fruits and vegetables, including (but not limited to) broccoli, carrots, cantaloupe, sweet potatoes, and pumpkin.
It’s important to note that studies have shown that diet plays a lesser role than other potent, cancer-increasing risk factors, such as alcohol and tobacco consumption. While studies have shown moderate risk reduction even for tobacco and alcohol consumers with higher intake of fruits and vegetables, the overall risk in tobacco and alcohol consumers is still higher (7).
This makes cessation a more important component of overall risk reduction than fruit and vegetable consumption, despite the high vitamin and mineral content of fruits and vegetables.
Research on Vitamin D and the prevention of various cancers has been of particular interest to researchers, as it was not previously believed to play a large role in the immune system. However, in recent years, Vitamin D has been shown to play a strong, protective role in various forms of cancer, including colorectal, breast, and prostate cancer (8).
Vitamin D intake in relation to oral cancers is of interest, but studies are few. While some studies have shown an inverse relationship between Vitamin D status and risk of oral cancer (9,10), the minimal number of studies on the topic leaves much room for additional research.
The body is able to synthesize Vitamin D with adequate exposure to natural sunlight. However, minimal exposure thanks to climate and geography, as well as the increased risk for skin cancers with prolonged exposure to UVB rays make this difficult. Additionally, dietary sources of Vitamin D are few. Dietary sources of Vitamin D include fatty fish (including but not limited to tuna, mackerel, sardines, and salmon) and mushrooms.
- Winn, DM. Diet and nutrition in the etiology of oral cancer. Am J Clin Nutr. 1995 Feb;61(2):437S-445S.
- Byers T, Guerrero N. Epidemiologic evidence for vitamin C and vitamin E in cancer prevention. The American Journal of Clinical Nutrition, Volume 62, Issue 6, 1 December 1995, Pages 1385S–1392S
- Chainani-Wu N, Epstein J, Touger-Decker R.Diet and prevention of oral cancer: strategies for clinical practice. J Am Dent Assoc. 2011 Feb;142(2):166-9.
- Garewal H. (1995) Beta-carotene and Antioxidant Nutrients in Oral Cancer Prevention. In: Prasad K.N., Santamaria L., Williams R.M. (eds) Nutrients in Cancer Prevention and Treatment. Experimental Biology and Medicine, vol 27. Humana Press, Totowa, NJ
- James Marshall, Saxon Graham, Curtis Mettlin, Donald Shedd & Mya Swanson (2009) Diet in the epidemiology of oral cancer, Nutrition and Cancer, 3:3, 145-149, DOI: 10.1080/01635588109513716
- Tanvetyanon T, Bepler G.Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands. Cancer. 2008 Jul 1;113(1):150-7. doi: 10.1002/cncr.23527.
- Macfarlane GJ, Zheng T, Marshall JR, Boffetta P, Niu S, Brasure J, Merletti F, Boyle P. Alcohol, tobacco, diet and the risk of oral cancer: a pooled analysis of three case-control studies. Eur J Cancer B Oral Oncol. 1995 May;31B(3):181-7.
- Gandini S, Boniol M, Haukka J, et al. Meta-analysis of observational studies of serum 25-hydroxyvitamin D levels and colorectal, breast and prostate cancer and colorectal adenoma. International Journal of Cancer. 2011;128(6):1414-1424.
- Lipworth L, Rossi M, McLaughlin JK, Negri E, Talamini R, Levi F, Franceschi S, La Vecchia C. Dietary vitamin D and cancers of the oral cavity and esophagus.Ann Oncol. 2009 Sep;20(9):1576-81. doi: 10.1093/annonc/mdp036. Epub 2009 Jun 1.
- Anouar Fanidi, David C. Muller. Circulating vitamin D in relation to cancer incidence and survival of the head and neck and oesophagus in the EPIC cohort Scientific Reports volume 6, Article number: 36017 (2016).