[Nutrition and cancer. Nutrition-associated risk for the development of various malignancies].

A scientific assessment of dietary risks encounters great difficulties, since reliable prospective studies are hardly possible, and the various forms of retrospective studies are associated with considerable error probabilities. Nevertheless, on the basis of the similar results obtained with numerous investigations, it is possible to make statements about definite or potential risks. Thus, the correlation between high levels of dietary fat and meat and colorectal cancer, and that between high levels of fat and mammary carcinoma, have been adequately demonstrated. Alcohol is a proven risk factor for numerous carcinomas of the gastrointestinal tract, in particular for tumors of the oropharynx and larynx, the esophagus and liver. But it may also be a possible risk factor for breast cancer and other gynecological tumors. Conversely, with respect to protective factors it is accepted that what is generally recognized to be a healthy diet (fruit, vegetables, fiber) can apparently offer a certain degree of protection from malignant disease.