The health benefits of olive oil are well known. Olive oil is the main source of fat shown to be associated with longevity in those persons living in the Mediterranean region.
Scientists have assumed previously that monounsaturated fat (MUFA) contained in olive oil was responsible for wellness and longevity. Recently, researchers have shown that the effects of polyphenols in olive oil are just as important as MUFA, if not more so. Maria Covas and co-workers studied 200 healthy men in six research centers located in five European countries. The participants were assigned to receive a daily administration of 25ml (about 2 tablespoons) of one of three different types of olive oil. The olive oil types had a concentration of polyphenols ranging from 2.7 mg/kg of olive oil (low-type) to 366 mg/kg (high) in the olive oils.
The results showed that there was a linear increase in the high density lipoprotein fraction (HDL-the good type) from the low to the high polyphenol containing olive oils. The low density lipoprotein (LDL-the bad type) was decreased following the intake of the oil containing the highest concentration of polyphenols when compared to the low polyphenol content olive oil. These changes are beneficial and accentuate the importance of extra virgin olive oil.
The scientists concluded that the polyphenols are equally (or more) important for a healthy heart than are the monounsaturated fats. The higher the polyphenol content the more strongly it correlated with a higher level of HDL lipoproteins (this is beneficial). Extra virgin olive oil contains the highest amount of polyphenols.
COVAS, M. et al, Ann Intern Med 2006: 145: 333-341 – The Effect of Polyphenols in Olive Oil on Heart Disease Risk Factors.