Partial conservation of the sn-2 position of dietary triglycerides in fasting plasma lipids in humans.

The authors investigated the effect of the position of fatty acids within dietary triglycerides on the composition of plasma lipids. Sixty volunteers consumed two diets of equal fatty acid compositions for 3 weeks each. In the palm oil diet 82% of palmitic acid was attached to the sn-1 and sn-3, and 18% to the sn-2 position of glycerol. In the diet rich in a palm oil analogue, Betapol, these figures were 35% and 65% respectively. Oleic and linoleic acid in palm oil were mainly in the sn-2 position, and in Betapol mainly in the sn-1 and sn-3 position. The proportion of palmitic acid in the 2 position of fasting plasma triglycerides was 10·2 g 100 g-1 on palm oil and 12·3 on Betapol; that of oleic acid was 46·dot 9 vs. 43·6 (P < 0·0001). Overall oleic acid content of triglycerides was 1·4 g 100 g-1 lower on Betapol than on palm oil (P = 0·002). Betapol increased palmitic and palmitoleic acid in cholesteryl esters by 1 g 100 g-1 (P < 0·0001) at the expense of oleic and linoleic acid. The positional configuration of dietary fatty acids has small but consistent effects on lipid metabolism that persist beyond fat absorption and chylomicron clearance.