ARTICLE NO. FC970554 EDITORIAL Diet and Cancer: Some Thoughts for Future Research A report entitled ''Food, Nutrition, and the Prevention of Cancer: A Global Perspective'' 1 was released and discussed at a recent international meeting in Washington DC sponsored by the American Institute for Cancer Research. The thrust of this report was that cancer appeared to be (at least in part) a preventable disease, and it recommended an increased consumption of fruits and vegetables that should play a major role in the prevention of most cancers. This was a useful recommendation and I believe that we can do more than just suggest that people eat more fruits and vegetables.
A historical perspective can be provided by reminding people of some nutrition history. At one time there were some diseases that ravished the United States (and world) population. These diseases were major causes of death and in many cases were direct contributors to mental disease. After intensive studies, it was recognized that increased consumption of some foods was known to help prevent these diseases. However, these diseases still were a major scourge of mankind. A number of pioneering chemists isolated and characterized those diet components that prevented the diseases. The disease preventing diet components were synthesized and/or isolated in bulk and a three-pronged attack on the diseases was launched. These approaches were fortification of selected foods, manufacturing and distribution of supplements containing the anti-disease components, and education programs to convince people to undertake diet modification to consume more of the foods that contained the antidisease components. These approaches were so successful that these diseases became rare medical curiosities in many countries. Some of the nutritional diseases that were eliminated in many parts of the world are beriberi, pellagra, and goiter. There are many other vitamin and mineral deficiency diseases whose occurrences have been drastically reduced. I would like to suggest that this vitamin story is a good model for future research on diet and cancer. The diet and cancer epidemiologists have been very successful. They have identified many of the probable sources of dietary anticancer compounds. The strongest evidence points to high consumption of fruits and vegetables. The findings on the exact components in fruits and vegetables that have the anti-cancer activity are more sketchy. Thus, we do not know why diets high in fruits and vegetables reduce the risk of cancer. This should not be unexpected. The chemical composition of plants is very complex. Best estimates of the composition of plants yield the following numbers of compounds and their precursors and derivatives: 120 amino acids; 100 nucleotides; 100 fatty acids; 200 lipids; 250 carbohydrates; 300 vitamins, coenzymes, isoprenoids, and porphyrins; more than 5000 phytosterols, flavinoids, alkaloids, and anthrocyanins; about 5000 enzymes, other proteins and peptides; and unknown numbers of other compounds. The plant food composition data bases have pretty good data for traditional nutrients but have essentially no data for all the other compounds.