Diet and cancer prevention: evidence-based medicine to genomic medicine.

The practice of medicine, including health promotion and disease prevention, is on the verge of being revolutionized once again as the scientific and medical community transitions from evidence-based medicine to genomic medicine. Evidence-based medicine entails the systematic approach of formulating a question, developing literature search strategies, and evaluating and applying evidence to establish clinical practice guidelines. In 1982, when the National Research Council published the first comprehensive review of diet and cancer, the literature was primarily based on epidemiological studies, comparing dietary patterns between countries of low and high incidence for particular cancers.

Defining the state of knowledge with respect to food, nutrition, physical activity, and the prevention of cancer.

The 1997 World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) report, Food, Nutrition and the Prevention of Cancer: a global perspective, has become the most authoritative statement on the topic. WCRF International has begun the process of producing its second global report on food, nutrition, physical activity, and the prevention of cancer. The process is in three stages.

Diet, nutrition, and cancer prevention: the postgenomic era.

The genomic era of human nutrition is upon us: the human genome and several plant genomes have been characterized, and genetically modified foods are now abundantly available in the marketplace. The link between diet and cancer is well established, and new genomic technologies have made possible the investigation of nutritional modulation of the carcinogenesis pathway with nutrients, micronutrients, and phytochemicals. Current study of nutrient-modulated carcinogenesis involves exploring the effect of nutrients on DNA damage and repair mechanisms; DNA methylation, which influences gene expression and cellular phenotypes; antioxidant rearranging and oxidative stress; target receptors and signal transduction pathways; cell cycle controls and check points; apoptosis; and antiangiogenic processes.

The role of dietary supplements during cancer therapy.

This guide was compiled after recommendations by the American Institute for Cancer Research (AICR) Cancer Resource Advisory Council. It encompasses the AICR position on current issues in nutrition for cancer survivors during treatment and is intended to provide advice about dietary supplements for cancer survivors who are still being treated. Current scientific findings about the safety and effectiveness of some commonly used dietary antioxidants and nonantioxidant supplements during chemotherapy are presented and assessed.

Diet, nutrition and cancer prevention: where are we going from here?

Since the national declaration of the war on cancer three decades ago, research on carcinogenesis has yielded a tremendous knowledge base on cancer. Cancer cells are the result of multiple genetic defects resulting from exposure to environmental, dietary and infectious agents. Multistep and multistage carcinogenesis may span 20 y or more, a time that provides research and clinical opportunities to suppress this disease in its early and premalignant stages before clinical symptomatic, invasive stages.

NCI dietary guidelines: rationale.

The National Cancer Institute (NCI) believes that the potential for dietary changes to reduce the risk of cancer is considerable and that the existing scientific data provide evidence that is sufficiently consistent to warrant prudent interim dietary guidelines that will promote good health and reduce the risk of some types of cancer. Six interim dietary guidelines and their scientific rationale are discussed herein. The evidence presented for the scientific rationale is based on the 1982 National Academy of Sciences Committee report Diet, Nutrition and Cancer and NCI's own scientific reviews that link long-term dietary patterns with cancer risk.

A breast cancer Nutrition Adjuvant Study (NAS): protocol design and initial patient adherence.

To evaluate the feasibility of using a reduction in dietary fat intake as a component of treatment regimens for patients with resected breast cancer, a multi-disciplinary cooperative group protocol was developed. Females 50 to 75 years of age with stage II breast cancer who completed primary local therapy were eligible for randomization to a Control Dietary Group in which dietary fat intake was to remain unchanged from baseline level (at approximately 38% of calories derived from fat) and an Intensive Intervention Dietary Group designed to reduce dietary fat intake. Both Dietary Groups were given tamoxifen 20 mg/day.

Clinical trials in cancer prevention.

Research in cancer prevention can be divided into laboratory research, epidemiologic research, and clinical trials. When results from laboratory and/or epidemiologic research support the possibility of clinical cancer prevention, these leads should be subjected to study in clinical trials. If clinical trials produce positive results, wide application of these results to the relevant segments of the general population should then be emphasized.

A critical review of food fiber analysis and data.

Epidemiologists, research scientists, and dietitians need data on the dietary fiber content of foods. This article provides a provisional table on dietary fiber, compiled after a thorough search of the literature and a critical evaluation of the analytical methodology employed. To make fully understandable the limitations and problems associated with the current dietary fiber data base, a short review of what is meant by the term dietary fiber and the complex chemical structures of the major dietary fibers--cellulose, hemicellulose, pectin, and lignin--are presented.

The Diet and Cancer Branch, NCI: current projects and future research directions.

Diet, perhaps more than any other environmental factor, has a significant potential for reducing the incidence of cancer. It has been projected that as much as 35 percent of all human cancer can be prevented through effective dietary modification strategies. The comprehensive research program of the DCB significantly directs diet and cancer research toward the ultimate cancer prevention goal of modifying dietary habits of the general population for optimal health.

Development of a nutrient data system for international use: INFOODS (International Network of Food Data Systems).

The current interest in the area of nutrition, diet, and cancer has called attention to some major deficiencies in the data base available to support a variety of research activities in the field. These deficiencies have been especially evident in epidemiologic studies where attempts are being made to characterize the dietary differences existing among various populations who have markedly different incidences of chronic diseases, including cancers, thought to be associated with diet. Such studies have been able to characterize international differences in diet by broad, nutrient-food categorizations, but they suffer from a dearth of detailed information on the nutrient content of the enormous variety of foodstuffs consumed by different populations and by the subgroup populations within each of the countries or geographic areas.

International food component data system.

The International Network of Food Data Systems planning conference recommends establishing nomenclature and a system of coding for use in INFOODS. The International Food Naming System would facilitate collection, tabulation, storing, and retrieval of information. The system consists of two files for each food: one describing the name in a standardized manner and another reporting chemical and biological data.

Zinc and copper in infant diets.

The diets of 59 healthy Utah infants were examined for nutritional adequacy. The analysis included zinc and copper intake calculated from new assays of zinc and copper in commercial baby foods and table foods obtained at local retail outlets. Group averages showed adequate dietary intake, with copper the limiting nutrient.

Folacin in selected foods.

Representative values for folacin in 299 foods have been developed, based on an extensive literature review. A provisional table of these folacin values has been prepared for foods in 100-gm. portions and for specified weights, representing common household units.