The Effects of Glyceride Structure on Absorption and Metabolism

The subtle effects of the stereochemistry of acyl glycerols are apparent from the cited studies. It is not adequate to simply measure the fatty acid composition of dietary lipids or chylomicrons generated from them. To understand the importance of stereospecific acyl glycerols, simplification of the systems is necessary because of the incredible diversity found among dietary triacylglycerols. By feeding simple analogues corresponding to major triacylglycerols found in oils and fats it should be possible to determine the absorption, uptake into the mucosa, resynthesis into chylomicrons, and the stereospecificity that remains. Hydrolysis and uptake of these defined chylomicron triacylglycerols into adipose tissue or muscle could be followed and stereospecificity again determined in depot fats. Finally, the composition of the remnants, particularly the core and surface, and of the bound apoproteins needs to be related to their plasma residence time, hepatic removal, and deposition in nonhepatic tissues such as spleen, bone marrow, and arterial intima. Since increased serum cholesterol and atherogenicity in animals have been related to different dietary fats, some of the effects noted here, that is the retention of certain kinds of remnants in plasma, may lead to increased serum cholesterol and atherogenesis. We must study the metabolism of a few key stereospecific triacylglycerols in more detail to increase our understanding of their effects on hypercholesterolemia and atherogenesis.