Abstract
It is supposed that the rising incidence of cancers of the breast and colon in postwar Japanese people may be relevant to the rapid westernization of their diet style. Some of both epidemiological and animal experimental studies have been reported on the relation of the increase in intake of fat among other diet components to the incidence of these cancers. Recent studies have proved that effects on these cancers are greatly different by the type of fatty acids contained in the fatty diet rather than the quantity of the fat intake itself. Some proofs have been furnished that n-6 polyunsaturated fatty acids promote these cancers while n-3 polyunsaturated fatty acids inhibit them. This paper describes the promoting and inhibiting effects of dietaly fat on cancers of the breast and colon, and their mechanism.
