January 2000, Volume 54, Issue 1, Pages 61 - 67

Original Communication

Comparison of an oleic acid enriched-diet vs NCEP-I diet on LDL susceptibility to oxidative modifications P Castro1, J López Miranda1, P Gómez1, DM Escalante1, F López Segura1, A Martín2, F Fuentes1, Á Blanco1, JM Ordovás2 & FP Jiménez1 1Lipids Research Unit, Hospital University Reina Sofia, Medical School, University of Córdoba, Spain; and     2The Lipid Metabolism Laboratory, USDA, Human Nutrition Research Center on Aging at Tufts University, Boston, USA     Correspondence to: Francisco Pérez Jiménez , Departamento de Medicina, Avda, Menéndez Pidal s/n, Facultad de Medicina, 14004, Córdoba, Spain.     Guarantor: FP Jiménez Contributors: P Gómez and MD Escalante, in vitro experiments of oxidation of LDL. A Martin and F López Segura the determination of -tocoferol. J López Miranda, selection of the populations, the control of the adherence of the diets and different biochemical determinations. A Blanco and F Fuentes the determinations of fatty acid composition and the control of the adherence of the diets. JM Ordovas provided advice during all the stages of the work and participated actively in data analysis and manuscript preparation. F Perez-Jimenez is the group leader and contributed to the experimental design and data analysis. P Castro contributed to the experimental design, the control of adherence of the diets, data analysis and prearation of the manuscript.

Keywords

oxidized low density lipoproteins ;   -tocopherol;   phospholipid;   monounsaturated fatty acids;   low fat diets;   fatty acids

Abstract

Objective: The objective of this trial was to compare the effect on the susceptibility of plasma Low Density Lipoprotein (LDL) to oxidative modifications of consumption of two oleic rich diets, prepared with two different plant oils, virgin olive oil (OL)1 and refined high monounsaturated fatty acids (MUFA sunflower oil (SU)), with the susceptibility of plasma LDL to oxidation after an National Cholesterol Education Program step 1 (NCEP-I) phase diet. Design: A randomized crossover design. Subjects and interventions: Twenty-two healthy normolipidemic young males consumed an NCEP-I diet for a 4-week period. Subjects were then assigned to two diets each of 4-weeks duration. Group one was placed on an olive oil enriched diet (40% fat, 22% MUFA) followed by a 4-week period of a MUFA diet enriched in sunflower oil (40% fat, 22% MUFA). In group two, the order of the diets was reversed. Results: Both MUFA diets induced a decrease in saturated (14:0, 16:0, and 18:0) and an increase in monounsaturated and polyunsaturated n-6 (18:2, 20:3, and 20:5) plasma LDL-phospholipid fatty acids, compared to the NCEP-I diet (P<0.01). No significant differences in lag times were observed between the olive oil and the NCEP-I diet periods. However there was a greater inhibition time (P<0.001) when subjects consumed the MUFA rich sunflower oil diet compared to the NCEP-I diet. These differences were probably related to the relative enrichment of plasma LDL particles in -tocopherol due to the high vitamin E content of the MUFA-rich sunflower oil. Indeed, the -tocopherol content was positively correlated with lag time (r=0.338; P<0.008). Conclusion: Our findings suggest that changes in plasma LDL -tocopherol content with practical solid-food diets can decrease its susceptibility to oxidation. Sponsorship: This work has been supported by grants from the Investigaciones de la Seguridad Social (FIS 92/0182, to Francisco Pérez Jiménez); and from Koype Co, Andújar, Jaén, Spain. European Journal of Clinical Nutrition (2000) 54, 61-67

Received 18 March 1998; Revised 18 March 1999; Accepted 30 March 1999

^© Macmillan Publishers Ltd 2000