Lack of influence of test meal fatty acid composition on the contribution of intestinally-derived lipoproteins to postprandial lipaemia

The extent and duration of postprandial lipaemia have been linked to risk o f CHD but the influence of dietary variables on, and the relative contribut ions of, exogenous (chylomicron) and endogenous (VLDL) triacylglycerols to the total lipaemic response have not been comprehensively evaluated. In the present study the triacylglycerol, apolipoprotein (apo) B-48 and retinyl e ster (RE) responses to three test meals of varying monounsaturated (MUFA) a nd saturated fatty acid (SFA) content were measured in the triacylglycerol- rich lipoprotein (TRL) fraction of plasma (rho = 1.006 g/ml) for 9 h after meal consumption. Fifteen healthy normolipidaemic young men consumed, on se parate occasions, three test meals which were identical apart from their MU FA and SFA contents. Expressed as a percentage of total energy the MUFA/SFA contents of the meals were: (1) 12 %/17 %; (2) 17 %/12 % and (3) 24 %/5 %. The contribution of the intestinally-derived lipoproteins (chylomicrons) t o the lipaemic response was investigated by determining the time to reach p eak concentration and the total and incremental areas under the time respon se curves (AUC and incremental AUC) for RE, apoB-48 and triacylglycerol in the TRL fraction. No significant differences in these measurements were obs erved for the three meals. However, visual comparison of the postprandial r esponses to the three meals suggested that as meal MUFA content increased t here was a tendency for the triacylglycerol, apoB-48 and RE responses to be come biphasic as opposed to the typical monophasic response seen with the 1 2 % MUFA/17 % SFA meal. Comparison of the apoB-48 and RE responses for the three test meals confirmed other workers' findings of delayed entry of RE r elative to apoB-48 in TRL. The value of the two markers in investigating di etary fat absorption and metabolism is discussed.