Fish oil reduces postprandial triglyceride concentrations without accelerating lipid-emulsion removal rates

Chronic intake of fish oil (FO) reduces postprandial lipemia. Our aim was to determine whether increased clearance of chylomicrons was the mechanism. Eight normal volunteers were randomly assigned to take 64 mg n-3 fatty acids/kg body wt or an olive oil placebo daily for 4 wk in a double-blind, crossover design. At the end of each phase, an intravenous fat-tolerance test and a four-meal, 24-h oral fat-load test were administered. The latter was designed to mimic normal eating patterns (fat provided 42% of energy). FO lowered chylomicron triglyceride and retinyl palmitate concentrations by 40% (P < 0.01) and very-low-density lipoprotein retinyl palmitate concentrations by 27% (P < 0.01). However, clearance rates of the fat emulsion were not significantly different between treatments. The results suggest that the hypochylomicronemic effect of chronic FO supplementation is not due to increased chylomicron clearance, leaving reduced chylomicron production or secretion as a more likely cause of the reduced postprandial lipemia.