Triglyceride Configuration and Fat Absorption by the Human Infant

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Abstract
A metabolic balance study was performed with 11 newborn infants fed formulas identical except for the type of fat. Five infants received a formula containing natural lard (palmitic acid primarily in the 2-position of the triglyceride molecule) while six infants received a formula containing randomized lard (palmitic acid equally distributed among the 1-, 2-, and 3-positions of the triglyceride molecule). Excretion of fat by infants fed the formula containing natural lard averaged 0.30 g/kg per day (range 0.15 to 0.50) while that by infants fed randomized lard averaged 1.79 g/kg per day (range 1.09 to 3.11). All of the fatty acids of the natural lard were absorbed better, but this was most marked in the case of palmitic and stearic acids. The greater absorption of palmitic acid from lard is believed to result from the greater content of 2-monopalmitin and the lower content of free palmitic acid present in the intestine after hydrolysis. Although there is no obvious mechanism to explain the greater absorption of stearic acid from lard, it may be due to a more rapid rate or greater extent of micellization in the presence of greater amounts of 2-monopalmitin.