Palmitic acid is absorbed as sn-2 monopalmitin from milk and formula with rearranged triacylglycerols and results in increased plasma triglyceride sn-2 and cholesteryl ester palmitate in piglets.
Milk fatty acids contain 20-30% palmitic acid (16:0), with approximately 70% of the 16:0 esterified to the sn-2 position of the milk triacylglycerol. Formulae containing vegetable and oleo oils contain different amounts of 16:0, but all have unsaturated fatty acids esterified to the triacylglycerol sn-2 position. Intraluminal triacylglycerol hydrolysis by endogenous lipases produces sn-2 monoacylglycerols and free fatty acids, which are absorbed and re-esterified in the enterocyte for secretion to plasma. The extent of absorption and re-esterification of sn-2 monoacylglycerols from milk or formula fats in infants is unknown. This was studied by feeding piglets sow milk or formulae containing similar total saturated fat, 18:1, 18:2(n-6) and 18:3(n-3) with unsaturated fatty acids at the sn-2 position or with rearranged triacylglycerols containing approximately 30% 16:0, with 70% 16:0 in fatty acids at the sn-2 position. Feeding milk or 16:0 on the sn-2 position of formula with rearranged triacylglycerols resulted in higher 16:0 esterified to the plasma triacylglycerol sn-2 position and in cholesteryl esters than feeding formulae with 0.4 to 4.4% 16:0 in the sn-2 position fatty acids. The absorption of 16:0 as monopalmitin from milk and any metabolic importance in human infants has yet to be determined.
Innis
S M
SM
Department of Paediatrics, University of British Columbia, Vancouver, Canada.
Dyer
R
R
Quinlan
P
P
Diersen-Schade
D
D
D000818:Animals; D002788:Cholesterol Esters / Q000097:blood*; D004952:Esters; D005227:Fatty Acids / Q000097:blood; D005526:Food, Formulated / Q000032:analysis*; D007408:Intestinal Absorption; D008297:Male; D008892:Milk / Q000737:chemistry*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000493:pharmacokinetics*; D010743:Phospholipids / Q000097:blood; D013552:Swine; D014280:Triglycerides / Q000097:blood / Q000737:chemistry*
D002788:Cholesterol Esters; D004952:Esters; D005227:Fatty Acids; D010169:Palmitic Acids; D010743:Phospholipids; D014280:Triglycerides; D019308:Palmitic Acid; C026651:cholesteryl palmitate