The role of foods and nutrients on oral and pharyngeal cancer risk.

The relation between selected aspects of diet and the risk of oral and pharyngeal cancer was considered in a few cohort studies and approximately 30 case-control studies. These studies reported consistent inverse associations with fruit and vegetable consumption. beta-carotene, vitamin C and selected flavonoids were also inversely related to risk, although it remains difficult to disentangle their potential effect from that of fruit and vegetables. Whole-grain cereals, but not refined grain ones, were also favorably related to the risk of oral and pharyngeal cancer. The results were not consistent for other foods, including meat, fish, eggs, milk and dairy products, but it is now possible to exclude a strong relation with oral and pharyngeal cancer risk. Data are also reassuring for coffee and tea, while hot maté drinking has been related to increased risk in studies from Argentina and Brazil. There is no consistent association with total fat intake, but monounsaturated fats (and olive oil) have resulted inversely related to risk. In developed countries, selected aspects of diet may account for 20% to 25% of oral and pharyngeal cancers. This proportion is likely greater in selected developing countries.