EFFECT OF FISH-OIL-ENRICHED MARGARINE ON PLASMA-LIPIDS, LOW-DENSITY-LIPOPROTEIN PARTICLE COMPOSITION, SIZE, AND SUSCEPTIBILITY TO OXIDATION

We investigated the effect of incorporating n-3 polyunsaturated fatty acids (PUFAs) into the diet on the lipid-class composition of LDLs, th eir size, and their susceptibility to oxidation. Forty-seven healthy v olunteers incorporated 30 g sunflower-oil (SO) margarine/d into their habitual diet during a 3-wk run-in period and then used either SQ or a fish-oil-enriched sunflower oil (FO) margarine for the following 4 wk . Plasma concentrations of total cholesterol, triacylglycerols, HDL ch olesterol, LDL cholesterol, and apolipoproteins A-I and B did not diff er significantly between the groups during intervention. The FO margar ine increased the concentration of n-3 very-long-chain PUFAs in the LD L particles, showing 93% (P less than or equal to 0.0001), 8% (P = 0.0 5), and 35% (P = <0.0001) increases in eicosapentaenoic acid, docosape ntaenoic acid, and docosahexaenoic acid, respectively, in the FO group compared with 3%, 7%, and 7%, respectively, in the SO group during th e intervention. The cholesterol content of the LDL particles increased in the FO group [total cholesterol: 6% (P = 0.008); cholesterol ester : 12% (P = 0.014)], although it was not significantly different from t hat in the control group, whereas the other lipid classes and the size of the LDL particles remained unchanged in both groups. A reduction i n the alpha-tocopherol content in LDL (6%, P = 0.005) was observed in the FO group. Ex vivo oxidation of LDL induced with Cu2+ showed a sign ificantly reduced lag time (from 91 to 86 min, P = 0.003) and lower ma ximum rate of oxidation (from 10.5 to 10.2 nmol.mg(-1).min(-1), P = 0. 003) after intake of the FO margarine. The results indicate that consu mption of the FO compared with the SO margarine had no effect on LDL s ize and lipid composition and led to minor changes in LDL alpha-tocoph erol content and oxidation resistance.