Retinyl palmitate is a reproducible marker for chylomicron elimination from blood

To study the individual variation in chylomicron clearance rate, young healthy volunteers were given a p.o. dose of 50,000 IU retinyl palmitate in the morning to label their chylomicrons. Serial blood samples were then obtained in the time interval 4-8 h after retinyl palmitate intake, to closely monitor the clearance of retinyl ester from the blood. The procedure was repeated in an identical way two days later. The calculated individual halflives for retinyl palmitate clearance ranged from 1.54 to 9.90 h, i.e. a more than five-fold variation. The intraindividual variation was much less (relative SD 11%). Retinyl palmitate clearance (and probably chylomicron clearance) is, thus, relatively constant within the same individual on different occasions but varies considerably between individuals.