Diet and Carcinogenesis
It is often believed that food and nutrition affect cancer risk only because diets may contain specific carcinogenic substances. Although various carcinogens have been identified in foods and beverages, these appear to contribute only slightly to the overall impact of diet on cancer risk. The most important effect of diet may be mediated by substances present in food that inhibit the cancer process. Nearly 200 studies in the epidemiologic literature have been reviewed and relate, with great consistency, the lack of adequate consumption of fruits and vegetables to the incidence of cancer.