Influence of Diet on the Phospholipid Fatty Acids of Growing Rats.

Abstract

Evidence has been presented 1 to show that the type of diet has a characteristic influence on the degree of unsaturation of the phospholipid fatty acids of various tissues of the cat. This influence of food fat may be divided into 2 categories: (1) in the intestinal mucosa and in the liver the phospholipid is involved in the absorption and assimilation of fat and undergoes an immediate change in composition during the absorption of a characteristic fat; (2) in all tissues studied (mucosa, liver, smooth and skeletal muscle) the degree of unsaturation of the phospholipid fatty acids is characteristic of the type of diet fed over a considerable period of time. This latter influence is probably the result of the utilization of the fatty acids of the food for the repair of the phospholipid broken down by the continuous wear and tear of cellular protoplasm.

The data presented in the accompanying table show that the type of diet has a distinct and uniform influence on the constitution of the phospholipid synthesized by young growing rats. Likewise the values given for the iodine numbers of the fatty acids of the neutral fat show the unmistakable influence of diet, thus confirming the findings of Shioji 2 and Anderson and Mendel. 3

Two facts are outstanding. It is evident that the neutral fat of the young control rats is similar in composition to that synthesized by the rats raised on a totally fat-free diet, while the phospholipid fatty acids of the latter are distinctly more saturated than those of the controls. This suggests that in the young controls (which had only recently been weaned) the neutral fat was synthesized from carbohydrate, but that the food contained a sufficient amount of unsaturated fatty acids to produce a highly unsaturated phospholipid.