EFFECTS OF A DIET RESTRICTED IN SATURATED FATTY-ACIDS AND CHOLESTEROLON THE COMPOSITION OF APOLIPOPROTEIN A-I-CONTAINING LIPOPROTEIN PARTICLES IN THE FASTING AND FED STATES

To test the hypothesis that diet may exert differential effects on apo lipoprotein (ape) A-I-containing high-density-lipoprotein (HDL) partic les with (w) and without (w/o) ape A-II [Lp(A-I w A-II) and Lp(A-I w/o A-II)], the effects of a diet low in saturated fatty acids and choles terol [National Cholesterol Education Panel (NCEP) Step 2 diet] on the se lipoproteins were determined in eight normolipidemic subjects, aged 53-74 y, in both the fasting and nonfasting states. Compared with a d iet high in saturated fatty acid and cholesterol, consumption of an NC EP diet (6 mo) lowered fasting plasma, low-density-lipoprotein, and HD L cholesterol, and nonfasting plasma cholesterol, triglyceride, and HD L cholesterol (P < 0.05- < 0.005). Phospholipid in fasting and nonfast ing Lp(A-I w A-II) and Lp(AI w/o A-II) was lower during the NCEP diet (P < 0.05-0.001), but reductions in ape A-I or A-II were observed only in Lp(A-I w A-II). In contrast, differences in particle-size profiles were detected in Lp(A-I w/o A-II) but not in Lp(A-I w A-II). These ob servations provide further evidence that Lp(A-I w A-II) and Lp(A-I w/o A-II) are distinct metabolic entities.