Influence of apolipoprotein-E phenotypes on postprandial lipoprotein metabolism after three different fat loads.

The aim of this study was to evaluate the postprandial response to three fat-loading tests in healthy subjects with different apolipoprotein E (apoE) phenotypes. Thirty-four subjects were studied: 15 with apoE3/3 (7 men and 8 women), 12 with apoE4/3 (5 men and 7 women), and 7 with apoE2/3 (4 men and 3 women). All received three oral fat loads at 1-wk intervals in meals rich in monounsaturated fatty acid, polyunsaturated fatty acid, and saturated fatty acid, with retinyl palmitate (60000 IU/m(2) of aqueous vitamin A) to quantify lipoproteins secreted by the intestine. No significant differences in postprandial lipoproteins were found between the three different fat loads. Peaks and incremental areas under the curve of retinyl palmitate in non-chylomicron fractions were higher in the apoE2/3- than in the apoE3/3- and apoE4/3-phenotype groups in meals rich in monounsaturated and polyunsaturated fatty acids (P < 0.05). When the three fat loads were analyzed together, the incremental area under the curve of retinyl palmitate was much higher in the apoE2/3- than in the other apoE-phenotype groups (P = 0.0004). In conclusion, the magnitude of intestinal lipoproteins after fat load, especially with monosaturated and polyunsaturated fatty acids, is higher in subjects with apoE2/3 than in those with apoE3/3 and apoE4/3 phenotypes.