Diet and primary prevention of cancer.

Various assessments have been made of the contribution of diet to the risk of developing cancer in industrialized societies. The evidence available for a causal relationship between diet factors and cancer of specific sites is still incomplete and further research is needed to fill gaps in knowledge. Nevertheless given the limited effectiveness of available therapy in the treatment of established disease, preventive measures based on available evidence should receive active consideration, particularly as they are unlikely to be hazardous in other respects and as they approximate to changes in food supply and diet recommended for general health maintenance. Prevention must address itself to the nature of the food supply, to the choice of the foods that constitute the normal diet and the way in which these are stored and prepared both domestically and industrially. The objectives of a primary prevention programme would be to develop dietary intake patterns that would meet established requirements for health maintenance, would minimize the intake of carcinogens and optimize the intake of inhibitors. The feasibility of public health measures in respect of these objectives is examined and the cost effectiveness assessed. Potential problems arising from the implementations are considered. Measures include the modification of agricultural practices and of food processing techniques as well as various approaches to nutrition education, and modification of food intake patterns. It is concluded that considerable experience exists in other areas of nutrition intervention to suggest that primary prevention of cancer in respect of dietary factors is feasible and would complement other public health activities in this area.