Diet-disease relationships: public health perspectives.

Recent nutrition recommendations are directed towards prevention of chronic degenerative diseases, particularly coronary heart disease and cancer. This focus is in response to morbidity and mortality trends during this century. The evidence supporting such dietary changes remains inconclusive because of difficulties inherent in the measurement of usual dietary intake. The association between dietary fat and breast cancer is reviewed as an example of the problems faced in assessing whether a dietary component does alter the risk of disease. Current recommendations suggest a population-based approach to dietary modifications; the public health implications of this approach are discussed.