A new randomized controlled trial has shown olive oil polyphenols that decrease plasma LDL concentrations and LDL atherogenicity in a cohort of healthy European young men aged between 20 and 59 years.
The effects of olive oil polyphenols on plasma LDL concentrations and atherogenicity were determined in a crossover, randomized clinical trial RCT of 25 healthy European men (EUROLIVE study) consuming 25 ml of low- or high-polyphenol-content olive oil for three weeks.
Increased plasma LDL concentrations, especially the number of small LDL particles are one of the best accepted indicators for the risk of atherosclerosis and cardiovascular diseases (CVD). (Though CVD is a complex, multi-factorial disease and over-reliance should not be placed on a single biomarker).
This study (1) showed that both the number of total and small LDL particles decreased which support previous evidence indicating that olive oil polyphenols can contribute highly to the control of cardiovascular risk. A small human trial in 2004 established that olive polyphenols decreased the oxidative status of men who were already on a low anti-oxidant diet (2).
The Mediterranean diet, particularly a diet rich in olive oil, has been demonstrated to lower the risk of CVD in a large, multi-center, randomized trial of older people (aged 55 to 80) in comparison with other low fat diets (3). Participants in the olive oil arm of this study showed reduced systolic blood pressure, improved HDL/total cholesterol ratio and lower levels of the inflammatory indicator, C-reactive protein.
Hydroxytyrosol is the main antioxidant polyphenol in olive extract able to demonstrate an anti-inflammatory effect. Hydoxytyrosol is believed to help prevent oxidation of LDL cholesterol. It is thought that oxidized LDL particles are taken up by macrophages (scavenger cells) into blood vessel walls, which turns the macrophages into foam cells. These foam cells then become the foundation of an atherosclerotic plaque.