DIETARY FATTY-ACIDS AND CANCER

Results from epidemiologic studies are controversial with respect to t he relation between total dietary fat consumption and breast cancer ri sk; 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 relativ ely high intakes of long-chain n-3 fatty acids. and n-9 fatty acids pr esent in olive oil, reduce breast cancer risk by mechanisms that may i nvolve modification of the biosynthesis of eicosanoids from n-6 polyun saturated 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 produ ction, may enhance breast cancer invasion and metastasis; n-3 fatty ac ids may exert a suppressive effect. Although studies of prostate cance r are less advanced, the indication is that a high fat intake promotes the emergence of the metastatic phenotype; further research is requir ed 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 prost ate cancer progression.