Diet to Prevent Gastrointestinal Cancer?

Abstract

Correlations between dietary habits and the occurrence of certain cancers have been known for a long time. There is abundant, impressive, if somewhat controversial epidemiological data on this topic (Diet, Nutrition and Cancer 1982). However, even the strongest statistically significant correlation between intake of a certain food and incidence or mortality of a certain tumor is no proof of a causal relationship. Epidemiological and preclinical research have clarified some possible causal connections, especially in the gastrointestinal tract, but in many instances it has still not been determined whether specific dietary components or habits really have an etiological role, are carcinogens or cocarcinogens, or are rather “innocent bystanders,” i.e., markers, a consequence of malignant growth during the long phases of promotion and conversion (Fig. 1). Retrospective analyses are all of limited value and no substitute for the prospective trials which alone will bring definitive answers to which diet really enhances or hinders the development of a specific tumor and under what conditions.