Effect of meal fat quality on oxidation resistance of postprandial VLDL and LDL particles and plasma triacylglycerol level

This study was performed to examine the postprandial effects of meals conta ining dietary fats, with their natural fatty acid composition and tocophero l content, on the plasma triacylglycerols (TG) and tocopherols and on the r esistance of VLDL and LDL to oxidation. On six separate days eighteen healt hy male subjects were given low-fat meals (LF) or the LF meals enriched wit h sunflower oil (SO), rapeseed oil (RO), olive oil (OO), palm oil (PO), or butter (B) in a crossover design. The fat-rich meals all resulted in simila r postprandial TG responses while the LF test meal did not increase plasma TG level. The postprandial plasma fatty acid profile changed to resemble th e fatty acid composition of the ingested test fat. The alpha -tocopherol: g amma -tocopherol ratios in postprandial plasma and VLDL samples were greate r than in the test fats. We found that the resistance of VLDL particles to oxidation in the postprandial state as assessed from lag time was increased after the PO-rich meal as compared with the SO-rich meal (P = 0.018), and the propagation rate was greater after the SO- and RO-rich meals compared w ith the others (P < 0.001). The resistance of LDL particles to oxidation wa s unaffected by the meals. In postprandial VLDL samples, the content of <al pha>-tocopherol was greater after the OO- and SO-rich meals compared with t he meal rich in PO (P = 0.034 and 0.042 respectively). The gamma -tocophero l content of VLDL was highest after RO-meal as compared with all other test meals (P = 0.0019), and higher after SO as compared with B (P = 0.0148). L arge individual differences were noted. In conclusion, meals enriched with different fats lead to the formation of VLDL particles with varying resista nce to oxidation.