Deriving Policy from Evidence: Experience from the WCRF/AICR Report

• Published in: Critical reviews in food science and nutrition 2010-11, Vol.50 (sup1), p.22-23
• Main Author: Wiseman, Martin J.
• Format: Article
• Language: English
• ISSN: 1040-8398; 1549-7852
• DOI: 10.1080/10408398.2010.526856

Health is regarded as a basic human right. Governments, public health authorities, and health care and other professions have responsibilities to protect and promote public health. Policies to achieve this should be based on the best available evidence. Two fundamental questions follow from this statement: What is the best available evidence, and what are the processes best used to identify and use it to develop policies and actions? The maintenance of health requires an adequate supply of safe and varied food to meet human nutritional requirements. In many parts of the world in which food supplies are secure, the nature of the diet depends on decisions that people make, rather than their diets being restricted by supply. In these circumstances, rational choices can only be made if people have the relevant information and are educated to be able to use it. Even in regions in which the food supply is restricted, governments have responsibilities to ensure that the food supply is designed to protect and promote the health of their people as much as possible. It therefore follows that the protection of health requires that people have the necessary information from regulatory agencies to make informed choices about their diet and physical activity to make rational policy decisions. Although health concerns are only one among many considerations in people's food choices, and usually are not overriding, they can only be included if the information is available. Thus, it is important that people should be aware of the links between food and nutrition, and health and disease. Evidence of the relationship between food, nutrition, and physical activity comprises several different types. In the biomedical field, randomized, controlled trials are regarded as the best form of evidence. Observational evidence, of various types, is regarded as inferior because it is subject to confounding. Experimental evidence based on laboratory studies can provide valuable additional information. Although well-designed and well-conducted randomized trials provide the most robust answers (internal validity), the very stringency in their design often makes their generalizability (external validity) poor. In the context of the causation of cancer, it is important to consider the biology of the disease. The common cancers result from a decades-long process of cumulative cell damage. Trials, which rarely exceed a few years, are unlikely to be able to assess this damage directly over the w