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

Area of Science:

• Nutritional Biochemistry
• Cardiovascular Health

Background:

• Chronic fish oil (FO) intake is known to reduce postprandial lipemia.
• The precise mechanism underlying this effect, specifically regarding chylomicron metabolism, requires further elucidation.

Purpose of the Study:

• To investigate whether enhanced clearance of chylomicrons is the primary mechanism responsible for the hypolipidemic effect of chronic fish oil supplementation.
• To differentiate between reduced production versus increased clearance of chylomicrons following fish oil intake.

Main Methods:

• A double-blind, crossover study involving eight healthy volunteers.
• Participants received either fish oil (64 mg n-3 fatty acids/kg body weight) or an olive oil placebo daily for four weeks.
• Intravenous fat-tolerance and a 24-hour oral fat-load test were conducted at the end of each treatment phase.

Main Results:

• Fish oil supplementation significantly reduced chylomicron triglyceride and retinyl palmitate concentrations by 40% (P < 0.01).
• Very-low-density lipoprotein retinyl palmitate concentrations were also decreased by 27% (P < 0.01) with fish oil.
• No significant differences in the clearance rates of the administered fat emulsion were observed between the fish oil and placebo treatments.

Conclusions:

• The hypochylomicronemic effect of chronic fish oil supplementation is not attributed to an increased clearance of chylomicrons.
• Reduced production or secretion of chylomicrons is the more probable mechanism responsible for the observed reduction in postprandial lipemia after fish oil intake.