FASTING PLASMA TRIACYLGLYCEROL CONCENTRATIONS PREDICT ADVERSE CHANGESIN LIPOPROTEIN METABOLISM AFTER A NORMAL MEAL

The changes in lipoprotein metabolism which follow the ingestion of a large fat load have been well described. The hypothesis was tested tha t similar changes in lipoprotein metabolism would occur after a relati vely normal meal. Plasma and lipoprotein triacylglycerol, cholesterol and apolipoprotein concentrations were determined in twenty subjects ( ten female) given a mixed meal containing approximately one-third of t he daily intake of major nutrients in the typical Western diet. Fastin g plasma triacylglycerol concentrations (range 0.38-2.70 mm/l) and the postprandial rise in plasma triacylglycerol varied considerably betwe en subjects and were significantly associated (P < 0.01). The rise in plasma triacylglycerol corresponded to marked increases in the triacyl glycerol concentration of the triacylglycerol-rich lipoproteins (TRL; chylomicrons and very-low-density lipoproteins). TRL cholesterol also increased after the meal. An increase in high-density-lipoprotein (HDL )-triacylglycerol following the meal was accompanied by a decrease in HDL-cholesterol concentration, presumably due to the action of the cho lesteryl-ester transfer protein. The increases in HDL-triacylglycerol and in TRL-cholesterol were correlated with the postprandial rise in t riacylglycerol in the TRL (P < 0.01). We conclude that potentially adv erse changes occur in both triacylglycerol-rich and high-density lipop roteins following a typical mixed meal, as they do after large fat loa ds. The changes are exaggerated in those subjects with greater fasting plasma triacylglycerol concentrations.