Effects of palm oil and transesterified palm oil on chylomicron and VLDL triacylglycerol structures and postprandial lipid response

The effects of positional distribution of triacylglycerol (TAG) fatty acids to TAG structures in chylomicrons and VLDL, and to postprandial lipemia, w ere studied in 10 healthy premenopausal women using a 6-h oral fat load tes t and a randomized, double-blind cross-over design. Molecular level informa tion of TAG regioisomerism was obtained with a tandem mass spectrometric me thod. The positional distribution of fatty acids in chylomicron TAGs was si milar to the respective dietary fat; 79% of the analyzed regioisomers in pa lm oil and 84% of the analyzed regioisomers in transesterified oil were fou nd in chylomicron TAGs 3 h after the oral fat loads. VLDL TAGs were equal a fter the two fat loads in all but one regioisomer. Similarities in the fatt y acid compositions of chylomicron TAGs suggest that palmitic acid was abso rbed equally from both test fats. The proportion of palmitoleic acid in the chylomicrons was increased. Fat with palmitic acid predominantly in the sn -1 and sn-3 positions caused a larger incremental area of total TAGs in pla sma and reduced plasma insulin values at the beginning of the postprandial response (0-90 min) compared with fat with palmitic acid randomly distribut ed. jlr The relationship between TAG molecular structures in dietary fats a nd in lipoproteins provides new means for understanding the effects of fatt y acid positonal distribution on human lipid metabolism.