Nutrition and human cancer.

It is now widely accepted that nutrition is as important as tobacco as a cause of human cancer. However, whereas we can dispense with tobacco with general benefit to health, we cannot do without food. It is, therefore, necessary to determine the pattern of nutrition that is associated with the lowest overall cancer risk. This is made more difficult by the fact that some kinds of cancer are associated with overnutrition (e.g., that of the colon, breast, and prostate) and some with poor nutrition (e.g., esophagus, stomach, and liver). The tools to determine this are epidemiology, animal models, in vitro studies, and dietary intervention studies. These all have their strengths and weaknesses, which will be discussed. It is concluded that the major nutrition factors associated with increased cancer risk are: (a) overweight [as a surrogate for excess energy intake]; (b) low intake of fresh fruit; (c) low intake intake of vegetables; and (d) low intake of whole-grain cereals. There have been many other associations with cancer at specific sites noted in the literature. However, it is the overall risk of cancer that must be minimized.