The Influence of Dietary Fats on Serum Cholesterol Levels in Cholesterol-Fed Chicks

Abstract

Studies upon cholesterol-fed chicks demonstrate that the kind of dietary fat has a pronounced influence upon the serum cholesterol level. Three breeds of chicks demonstrated only minor differences. The serum cholesterol levels appear to be proportional to the log of the dietary cholesterol, other things being equal. The data demonstrate that fats high in saturated fatty acids promote hypercholesterolemia and that this effect is counteracted by unsaturated fatty acids. The polyunsaturated acids (primarily linoleic acid in the fats studied) appear considerably more active than the monounsaturated acids but the data do not permit a clear-cut distinction between linoleic acid and unsaturation per se as the primary cholesterol lowering factor. Equally good correlation between serum cholesterol and iodine number (total unsaturation) and with multiple regression equations involving the different classes of fatty acids was found. The coefficients of parital correlation suggest that iodine number may be of more significance than the polyunsaturated fatty acid content. The data also contain evidence that corn and cottonseed oil may contain factors which lower the serum cholesterol, which cannot be accounted for by the fatty acid composition. It appears that the chick, fed cholesterol, may be a valuable model for studies in the area of dietary fat-serum cholesterol relationships and the findings may have application in human nutrition.