title: Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation--a randomized controlled trial.
abstract: BACKGROUND
  Evidence from in vitro studies suggests that antioxidant olive oil phenolic compounds can prevent LDL oxidation. However, in vivo evidence in support of this hypothesis is sparse.
  
  
  OBJECTIVE
  to establish the antioxidant effect of olive oils with differences in their phenolic compounds content in humans
  
  
  METHODS
  A controlled, double blind, cross-over, randomized, clinical trial using three similar olive oils with increasing phenolic concentration (from 0 to 150 mg/Kg) was conducted in 30 healthy volunteers. Olive oils were administered over three periods of 3 weeks preceded by two-week washout periods.
  
  
  RESULTS
  Urinary tyrosol and hydroxytyrosol increased (p < 0.020), in vivo plasma oxidized LDL decreased (p = 0.006), and ex vivo resistance of LDL to oxidation increased (p = 0.012) with the phenolic content of the olive oil administered. After virgin olive oil administration, an increase (p = 0.029) was observed in HDL cholesterol levels.
  
  
  CONCLUSIONS
  Sustained consumption of virgin olive oil with the high phenolic content was more effective in protecting LDL from oxidation and in rising HDL cholesterol levels than that of other type of olive oils. Dose-dependent changes in oxidative stress markers, and phenolic compounds in urine, were observed with the phenolic content of the olive oil administered. Our results support the hypothesis that virgin olive oil consumption could provide benefits in the prevention of oxidative processes.
authors.affiliation: Lipids and Cardiovascular Epidemiology, Research Unit, Institut Municipal d'Investigació Mèdica, Carrer Dr Aiguader 80, 08003 Barcelona, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Marrugat
authors.forename: María-Isabel
authors.initials: MI
authors.lastname: Covas
authors.forename: Montserrat
authors.initials: M
authors.lastname: Fitó
authors.forename: Helmut
authors.initials: H
authors.lastname: Schröder
authors.forename: Elisabet
authors.initials: E
authors.lastname: Miró-Casas
authors.forename: Eva
authors.initials: E
authors.lastname: Gimeno
authors.forename: M Carmen
authors.initials: MC
authors.lastname: López-Sabater
authors.forename: Rafael
authors.initials: R
authors.lastname: de la Torre
authors.forename: Magí
authors.initials: M
authors.lastname: Farré
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000097:blood; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D008077:Lipoproteins, LDL / Q000737:chemistry* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000494:pharmacology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000652:urine; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D008076:Cholesterol, HDL; D008077:Lipoproteins, LDL; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol; D010626:Phenylethyl Alcohol