Dietary modifiers of cancer.

The foregoing review of current risk factors associated with single nutrients and nutritional status in human populations, supported by animal studies, point clearly to a possibility for manipulation of nutrients in our diet, which may be a major tool for prevention of cancer. Migrant populations exhibit changes in incidence and frequency of certain types of cancer indicating external causes for cancer with diets high on the list of suspects. The foods we eat are probably the most important risk factors that human populations encounter and they offer a major focus for hope of preventing cancer. Food is also the most complex mixture to which we are exposed. Of all lifestyle factors associated with cancer, diet is one over which we exercise control. Epidemiologic observations, supported by controlled animal model research on carcinogenesis strongly suggest that through dietary control, some types of cancer are preventable. The evidence to date suggest that of all dietary factors of significance, those most likely to affect risk include total calories, protein, fat, vitamin A and carotene, the lipotropic factors methionine and choline, and the minerals zinc and selenium.