The Metabolism of Native and Randomized Butterfat Chylomicrons in the Rat Is Similar

Reportedly, randomly rearranging the position of fatty acids (FA) in butterfat triacylglycerol (TAG) by interesterification, thereby lowering the proportion of saturated FA in the sn-2 position, reduces its hypercholesterolemic and hypertriglyceridemic properties when fed to humans. The aim of this work was to determine if these reductions in plasma cholesterol and TAG could be explained by an improved rate of clearance from the plasma of chylomicrons composed of randomized butterfat, using a rat model. Acute chylomicron clearance studies demonstrated no differences in fractional clearance rates pf cholesteryl esters and TAG from the plasma of rats infused with chylomicrons produced from gastric feeding of either native (NBF) or randomized (RBF) butterfat. Although there was a 14% decrease in the level of saturated EA occupying the sn-2 position of TAG in RBF compared with NBF, this difference became negligible (similar to 5%), following digestion of the fat and subsequent repackaging of TAG into chylomicrons. These observations suggest that the previously observed reduction in hypercholesterolemic properties of randomized butterfat in rat is unlikely to be explained by improved clearance of chylomicron TAG.