Influence of Various Dietary Fats on

• It is evident that both dietary and meta-bolic factors influence plasma cholesterol levels and the development of experimental athero-sclerosis. The type of fat normally consumed is one of the important dietary factors. Al-though the "polyunsaturated " fatty acids (con-sisting primarily of linoleic acid) are known to depress plasma cholesterol levels, it does not follow that an excess of dietary linoleic acid is necessarily more beneficial than a proper ratio of fatty acids of different chain length and saturation. The literature indicates a striking disparity between the effects of various dietary fats on plasma cholesterol levels in human beings and in animals.1 '- We ourselves were unable, in earlier studies, to find consistent differ-ences in hypercholesterolemia and athero-genesis in cockerels fed different saturated and unsaturated fats added to cholesterol supple-mented chick starter mash.8 This may have been due to the presence in this mash of 3 to 5 % of fatty acids of variable composition. In the present study, therefore, a fat-free, semi-synthetic diet was used as the basic ration