Effect of triglyceride structure on fat absorption.

Stereospecific distribution of fatty acids on triacylglycerol structures influences the technological behavior of fats as well as their absorption fate. Long-chain fatty acids in external (sn-1 and sn-3) positions may impair fat absorption and therefore the physiological response to dietary fats. Lower digestibility of bovine milk fat compared with that of human milk is related to the different position of palmitic acid in both fats. Stereospecific analysis of cocoa butter and fats containing stearic acid of the stearic-oleic-stearic acid (SOS) type showed that long-chain saturated fatty acids are almost exclusively present in sn-1 and sn-3 positions, which could explain their impaired absorption and therefore their neutral effect on serum lipid in humans despite their saturation and chain length. The true energy value of these fats therefore needs to be verified in mixed diets.