THE EFFECT OF TRIGLYCERIDE POSITIONAL DISTRIBUTION ON FATTY-ACID ABSORPTION IN RATS

Background: Human milk contains palmitic acid predominantly in the tri glyceride sn-2 position, and differs from the palmitic acid positional distribution found in most infant formulas (predominantly positions s n-1 and sn-3). Following lipolysis by pancreatic lipase, 2-monoglyceri des and free fatty acids are produced. All 2-monoglycerides are well a bsorbed, including 2-monopalmitin, thus providing one reason for the e fficient absorption of palmitic acid in breast-fed infants. If infants are fed fat blends with palmitic acid located in the sn-l and sn-3 po sitions, the resulting free fatty acids may form poorly absorbed calci um soaps. Therefore, many infant formulas contain only modest levels o f palmitic acid. Methods: Fat absorption studies were conducted in rat s with preparations containing various amounts of palmitic acid in the triglyceride sn-2 position. Determining total fat absorption, specifi c fatty acid absorption, and the presence of calcium-fatty acid soaps. Results: Betapol, a new triacylglycerol, similar to human milk in its palmitic acid content and positional distribution, demonstrated excel lent absorption characteristics compared to fat blends derived from ei ther palm olein or oleo (similar in fatty acid profile to Betapol, but with most palmitic acid in the sn-1 and sn-3 positions). A five-point dose response was used to further evaluate the relationship of positi onal distribution and fat loss. Palmitic acid excretion and fecal fatt y acid soaps were negatively correlated to the presence of palmitic ac id in the sn-2 position. Conclusion: These studies provide evidence th at palmitic acid can be efficiently absorbed, avoiding fatty soap form ation of it is present in the sn-2 position.