DIFFERENT POSTPRANDIAL METABOLISM OF OLIVE OIL AND SOYBEAN OIL - A POSSIBLE MECHANISM OF THE HIGH-DENSITY-LIPOPROTEIN CONSERVING EFFECT OF OLIVE OIL

The postprandial lipoprotein metabolism of two orally administered vit amin A-fat loads consisting of either 20% (wt:vol) soybean oil or 17% olive oil plus 3% soybean oil was studied in six normolipidemic young men according to a randomized crossover design. Mean (+/-SEM) retinyl palmitate concentrations (area under the 24-h curve) were higher in ol ive oil chylomicrons (97.3 +/- 5.5 mmol . L-1 . h-1), than in soybean- oil chylomicrons (84.0 +/- 10.5 mmol . L-1 . h-1; P < 0.02). Apolipopr otein B-48 concentrations were higher in the olive oil chylomicron rem nants with densities (d) of 1.006-1.019 compared with soybean-oil remn ants. The slower removal of olive oil chy- with soybean-oil remnants. The slower removal of olive oil chylomicron remnants was correlated to hepatic lipase activity (r = 0.84, P < 0.02). The initial HDL-cholest erol concentration (0.87 +/- 0.17 mmol/L-relatively low but within the normal range for young Dutch men) decreased significantly after inges tion of soybean oil to 0.66 +/- 0.10 mmol/L after 5 and 7 h, but no si gnificant decrease was observed after olive oil ingestion. Soybean oil induced decreases in HDLs correlated inversely with hepatic lipase (r = -0.88, P < 0.02). The results suggested that competition between ol ive oil chylomicron remnants and HDL for hepatic lipase may have been the underlying mechanism that prevented the postprandial decrease in H DL cholesterol.