Dietary fatty acids and cancer.
Results from epidemiologic studies are controversial with respect to the relation between total dietary fat consumption and breast cancer risk; there is more general agreement that a high-fat diet is associated with aggressive prostate cancer. Recent epidemiologic investigations and laboratory experimentation with animal models suggest that relatively high intakes of long-chain n-3 fatty acids, and n-9 fatty acids present in olive oil, reduce breast cancer risk by mechanisms that may involve modification of the biosynthesis of eicosanoids from n-6 polyunsaturated fatty acids. Although there is only limited support for the hypothesis that total fat intake affects breast cancer risk, there is experimental evidence that n-6 fatty acids, again via eicosanoid production, may enhance breast cancer invasion and metastasis; n-3 fatty acids may exert a suppressive effect. Although studies of prostate cancer are less advanced, the indication is that a high fat intake promotes the emergence of the metastatic phenotype; further research is required to establish the roles of the various classes of fatty acids but it does appear that the long-chain n-3 fatty acids may also retard prostate cancer progression.