Foods, nutrients and the risk of oral and pharyngeal cancer

Background: Besides tobacco and alcohol, dietary habits may have a relevant role in oral cavity and pharyngeal (OCP) cancer. Methods: We analysed the role of selected food groups and nutrients on OCP cancer in a case-control study carried out between 1997 and 2009 in Italy and Switzerland. This included 768 incident, histologically confirmed squamous cell carcinoma cases and 2078 hospital controls. Odds ratios (ORs) were estimated using logistic regression models including terms for tobacco, alcohol and other relevant covariates. Results: Significant inverse trends in risk were observed for all vegetables (OR = 0.19, for the highest vs the lowest consumption) and all fruits (OR = 0.39), whereas significant direct associations were found for milk and dairy products (OR = 1.50), eggs (OR = 1.71), red meat (OR = 1.55), potatoes (OR = 1.85) and desserts (OR = 1.68), although trends in risk were significant only for potatoes and desserts. With reference to nutrients, significant inverse relations were observed for vegetable protein (OR = 0.45, for the highest vs the lowest quintile), vegetable fat (OR = 0.54), polyunsaturated fatty acids (OR = 0.53), alpha-carotene (OR = 0.51), beta-carotene (OR = 0.28), beta-cryptoxanthin (OR = 0.37), lutein and zeazanthin (OR = 0.34), vitamin E (OR = 0.26), vitamin C (OR = 0.40) and total folate (OR 0.34), whereas direct ones were observed for animal protein (OR = 1.57), animal fat (OR = 2.47), saturated fatty acids (OR = 2.18), cholesterol (OR = 2.29) and retinol (OR = 1.88). Combinations of low consumption of fruits and vegetables, and high consumption of meat with high tobacco and alcohol, led to 10- to over 20-fold excess risk of OCP cancer. Conclusion: Our study confirms and further quantifies that a diet rich in fruits and vegetables and poor in meat and products of animal origin has a favourable role against OCP cancer.