Effect of Positional Distribution on the Absorption of the Fatty Acids of Human Milk and Infant Formulas

Abstract

A fat absorption study was conducted in rats to determine if the unusually high proportion of palmitic acid in the 2-position of triglycerides could be related to the superior absorption of human milk fat. Digestion yields free fatty acids and 2-monoglycerides. The monoglycerides of the saturated fatty acids are more readily absorbed than the free acids. Tests run on a number of fats commonly fed to infants, showed that the high absorption of human milk fat, 94.6 (%), was equaled by a fat blend of a similar fatty acid composition with a high content of 2-palmitoyltriglyceride, 96.3, in contrast to one with low content, 89.9. Absorption of butterfat was 89.5, lard 92.4 and oleo 79.9. Individual fatty acid absorption was influenced by total fat absorption. A linear relationship between absorption and the proportion in the 2 position was demonstrated for palmitic, and to a lesser extent, for myristic and oleic, but not for stearic acid. Equations predicting fat absorption required emphasis of the product of stearic acid and palmitic acid esterified in the primary positions.