Effect of 6 dietary fatty acids on the postprandial lipid profile, plasma fatty acids, lipoprotein lipase, and cholesterol ester transfer activities in healthy young men.

BACKGROUND: There is increasing evidence that postprandial triacylglycerol-rich lipoproteins may be related to atherogenic risk.

OBJECTIVE: The objective was to investigate the effect of individual fatty acid intakes on postprandial plasma lipoprotein triacylglycerol and cholesterol concentrations, plasma fatty acids, and preheparin lipoprotein lipase and cholesterol ester transfer protein (CETP) activities.

DESIGN: Six test fats high (approximately 43% by wt) in stearic acid, palmitic acid, palmitic + myristic acid, oleic acid, elaidic acid (trans 18:1), and linoleic acid were produced by interesterification. After having fasted for 12 h, 16 healthy young men were served the individual test fats incorporated into meals (1 g fat/kg body wt) in random order on different days separated by washout periods. Blood samples were drawn before and 2, 4, 6, and 8 h after the meals.

RESULTS: Different responses to the test-fat meals were observed for plasma lipoprotein triacylglycerol and cholesterol concentrations, plasma fatty acid concentrations, and lipoprotein lipase and CETP activities (diet x time interaction: 0.001 < P < 0.05). Intake of the long-chain saturated fatty acids stearic and palmitic acids resulted in a relatively lower lipemic response than did intake of the unsaturated fatty acids, probably because the saturated fatty acids were absorbed less and at a lower rate; therefore, the lipemic response took longer to return to postabsorptive values.

CONCLUSIONS: Fatty acid chain length and degree of saturation appear to affect the extent and duration of lipemia and affect hepatic output indirectly. These effects may not be mediated via effects on lipoprotein lipase and CETP activities.