Lipoprotein concentrations in normolipidemic males consuming oleic acid-rich diets from two different sources: olive oil and oleic acid-rich sunflower oil.

The effects on plasma lipid concentrations of two oleic acid-rich diets, prepared with two different plant oils-olive oil and sunflower oil high in monounsaturated fatty acids (MUFAs)-were compared with a National Cholesterol Education Program (NCEP) I diet. Twenty-one healthy, normolipidemic, young males consumed an NCEP-I diet (30% of energy as fat) during a 25-d period. Subjects were then assigned to two 4-wk study periods, according to a randomized, crossover design. Group one was placed on an olive oil-enriched diet (40% fat, 22% MUFAs), followed by a 4-wk period of a sunflower oil-enriched diet (40% fat, 22% MUFAs). In group two, the order of the diets was reversed. Both MUFA dietary periods resulted in an increase in high-density-lipoprotein (HDL) cholesterol (7% for the olive oil diet and 4% for the sunflower oil diet) and in apolipoprotein (apo) A-I (9% for both) compared with the NCEP-I diet. Low-density-lipoprotein (LDL) cholesterol and apo B concentrations (x ± SEM) were lower (P < 0.05) during the sunflower oil diet (2.40 ± 0.11 mmol/L, 0.85 ± 0.04 mg/L) than during the olive oil diet (2.64 ± 0.15 mmol/L, 0.93 ± 0.05 mg/L). No significant differences were observed in these variables between the sunflower oil and NCEP-I (2.48 ± 0.13 mmol/L, 0.89 ± 0.04 mg/L) diets. Because the plant sterol composition and non-fatty acid constituents were different in both MUFA diets, our findings suggest that minor constituents in the oils may account for some of the differences in plasma lipid concentrations observed after diets similar in fatty acid content.