Plasma lipoprotein fatty acids are altered by the positional distribution of fatty acids in infant formula triacylglycerols and human milk.
BACKGROUND
Triacylglycerol digestion involves hydrolysis of fatty acids esterified at the glycerol 1,3 positions by gastric and pancreatic lipase to produce 2-monoacylglycerols and unesterified fatty acids, which are then absorbed, reesterified to triacylglycerol, and secreted in chylomicrons. Palmitic acid (16:0) is predominantly esterified to the 2 position of human milk triacylglycerol but to the 1,3 positions in the oils used in infant formulas.


OBJECTIVE
We aimed to determine whether the position of 16:0 in human milk and infant formula triacylglycerol influences the position of fatty acids in postprandial plasma chylomicron triacylglycerol.


METHODS
Full-term infants were fed formula with 25-27% 16:0 with either 39% of the 16:0(synthesized triacylglycerol) or 6% of the 16:0 (standard formula) esterified at the triacylglycerol 2 position, or were breast-fed (23% 16:0, 81% at the triacylglycerol 2 position) from birth to 120 d of age. Chylomicron fatty acids and plasma lipids were assessed at 30 and 120 d of age.


RESULTS
Infants fed the synthesized triacylglycerol formula, standard formula, or breast milk had 15.8%,8.3%, and 28.0% 16:0 in the chylomicron triacylglycerol 2 position (P < 0.05). These results suggest that >/=50% of the dietary triacylglycerol 2-position 16:0 is conserved through digestion, absorption, and chylomicron triacylglycerol synthesis in breast-fed and formula-fed infants. Infants fed the synthesized triacylglycerol formula had significantly lower HDL-cholesterol and apolipoprotein A-I and higher apolipoprotein B concentrations than infants fed the standard formula.


CONCLUSIONS
Dietary triacylglycerol fatty acid distribution may alter lipoprotein metabolism in young infants.
Nelson
C M
CM
Department of Paediatrics, University of British Columbia, Vancouver, Canada.
Innis
S M
SM
D002788:Cholesterol Esters / Q000097:blood; D002914:Chylomicrons; D005227:Fatty Acids / Q000032:analysis* / Q000097:blood*; D006801:Humans; D007223:Infant; D007225:Infant Food; D008074:Lipoproteins / Q000097:blood*; D008895:Milk, Human / Q000737:chemistry*; D011446:Prospective Studies; D014280:Triglycerides / Q000008:administration & dosage / Q000737:chemistry*; D015430:Weight Gain
D002788:Cholesterol Esters; D002914:Chylomicrons; D005227:Fatty Acids; D008074:Lipoproteins; D014280:Triglycerides