COMPOSITION OF HUMAN VLDL TRIACYLGLYCEROLS AFTER INGESTION OF OLIVE OIL AND HIGH OLEIC SUNFLOWER OIL

This work was undertaken to determine the effect of diets enriched wit h olive oil or high oleic sunflower oil on very low density lipoprotei n (VLDL) triacylglycerol composition of healthy human subjects. Both o ils contain a similar proportion of monounsaturated fatty acids (MUFA) but differ in their triacylglycerol composition. All 22 human subject s initially consumed a low fat, high carbohydrate diet as recommended by the National Cholesterol Education Program (NCEP-I). They then cons umed the two experimental oils (40% dietary energy) in a crossover des ign. The olive oil and high oleic sunflower oil diets resulted in sign ificant increases in palmitoleic (55%, P < 0.05), oleic (27%, P < 0.01 ) and eicosenoic (>100%, P < 0.001) acids of VLDL triacylglycerols, wh ereas there was a significant decrease in linoleic acid (38%, P < 0.00 1). In addition, the high oleic sunflower oil diet increased the conte nt of stearic acid (60%, P < 0.05) and total saturated fatty acids (14 %, P < 0.05). Both MUFA-rich diets significantly (P < 0.01) decreased the content of sn-glycerol-palmitate-linoleate-oleate, sn-glycerol-pal mitoleate-dioleate and sn-glycerol-palmitate-dilinoleate in VLDL with regard to the NCEP-I diet, whereas they increased the content of sn-gl ycerol-trioleate (>100%, P < 0.001 after the olive oil diet; 80%, P < 0.05 after the high oleic sunflower oil diet). Intake of olive oil, in particular, significantly decreased the content of sn-glycerol-tripal mitate (36%, P < 0.01) and increased the content of dioleoyl-containin g triacylglycerols, MUFA (P < 0.01) and arachidonic acid (P < 0.001) t ended to be rich in the sn-2 position of VLDL triacylglycerols during the periods of consuming the olive oil or high oleic sunflower oil die ts. In addition, olive oil, but not high oleic sunflower oil, further contributed to VLDL triacylglycerols that contained cr-linolenic and d ocosahexaenoic acids acylated in the sn-2 position. These data suggest that differences in the composition of VLDL triacylglycerols may be o f major importance in explaining the beneficial effects of dietary oli ve oil in reducing the atherogenic risk profile in healthy subjects.