The Absorbability of Stearic Acid when Fed as a Simple or Mixed Triglyceride

Abstract

Rats were fed a series of fats in which the level of stearic acid and the distribution of the stearic acid among simple and mixed triglycerides were varied. The coefficients of absorbability of these fats were determined. From the results obtained it is shown that the stearic acid of tristearin is not absorbed. On the other hand, the stearic acid of distearin-monounsaturated or monostearin-diunsaturated triglycerides is almost completely absorbed. These results show that the theory which holds that the coefficient of absorbability of fat is a function of its content of saturated fatty acids containing 18 or more carbon atoms is not tenable. Since natural fats do not have a sharp melting point but melt over a temperature range, it is not reasonable to continue to use melting point as a parameter in fat utilization studies. It is concluded that the coefficient of absorbability of a fat is inversely proportional to its content of simple triglycerides made up of saturated fatty acids having a chain length of 18 carbon atoms or greater and is influenced by the level of such saturated fatty acids only insofar as they are present as saturated triglycerides.