How strong is the evidence on the role of diet, nutrition, physical activity and cancer?


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Martin Wiseman1
1World Cancer Research Fund

Abstract

Background

Here is considerable geographic variation in the incidence of cancers, but it is not fixed. Patterns of cancers change over decades within countries, and in migrating populations within one to two generations. There are consistent associations between consumption of food and drinks, adiposity or physical activity and cancer risk. Experimental evidence has demonstrated a plausible biological basis for causal connections between nutrition and cancer. In particular obesity is a contributory cause for at least 12 cancers. Greater adherence to recommendations for cancer prevention based on these findings predicts lower incidence and mortality from specific cancers, and from cancer in general, as well as all-cause mortality. Adherence to the recommended pattern of diet and activity is commonly low, and education and information alone are not effective in generating sustained or substantial change in behaviour. The major determinants of patterns of diet and activity in populations are not personal (knowledge, attitudes, beliefs) but are outside people's personal control, at local, national or international level in social, economic, political or environmental domains. Policy for cancer prevention needs to address these high level structural factors. The WCRF Nourishing framework offers policy options that have been used around the world to address dietary cancer prevention.