Effect of consumption of phenols from olives and extra virgin olive oil onLDL oxidizability in healthy humans

A high intake of olive oil has been proposed as an explanation for the low incidence of coronary heart disease in Mediterranean countries, but it is u nclear whether olive oil offers specific benefits beyond a low content of s aturated fat. Some types of extra virgin olive oil are rich in non-polar ph enols, which might be taken up by plasma LDL particles and protect these fr om becoming atherogenic by oxidative modification. In a pilot study we foun d that consumption of 47 g fortified olive oil containing 31 mg phenols sig nificantly increased the lag time of LDL oxidation from 112 +/- 5 min befor e to 130 +/- 7 min 2 h after the meal. However, this study was not controll ed, and in the current study we therefore investigated whether olive oil ph enols increase the lag time of LDL oxidation in postprandial samples when c ompared with a control group. Twelve healthy men and women consumed four different olive oil supplements with a meal on four separate occasions: one similar to the supplement in th e pilot study (positive control); one containing mainly non-polar olive oil phenols; one containing mainly polar olive oil phenols; and one without ph enols (placebo). Lag time significantly increased 2 h after the meals with the positive control (8 +/- 2 min), the polar phenols (8 +/- 2 min), and th e placebo (8 2 min), but not after the non-polar phenols (-0.4 +/- 3 min). Increases were not statistically different between supplements. These results indicate that the lag time of LDL-oxidation is increased afte r consumption of a meal. This increase is probably due to non-specific meal or time effects and not to phenols from olives or olive oil. Furthermore, these findings stress the need for adequate controlled studies to avoid mis interpretations of the data.