Recent News from the EUROLIVE Study

In the frame of the EUROLIVE Study a study on the absorption of olive oil phenolic compounds in the body has been assessed. 12 healthy male volunteers participated in the study. Before the study, volunteers were submitted to a low antioxidant diet which excluded the consumption of olive oil in order to avoid the interference of other antioxidants in the absorption of olive oil phenolic compounds. Volunteers ingested a dose of 25 mL of three similar olive oils, but with differences in their phenolic content: virgin (phenolic content = 366 ppm), common (phenolic content = 164 ppm), and refined (phenolic content = 2.7 ppm). We measured the levels of hydroxytyrosol and tyrosol, the two main olive oil phenolic compounds, in plasma and urine. Levels of these compounds in the body increased in a dose-dependent manner with the phenolic content of the olive oil administered.

Previous to the bioavailability study we performed a pilot study in which volunteers ingested a single dose of 25 mL of the high phenolic content olive oil, the virgin olive oil, and measured the levels of hydroxytyrosol in plasma and urine. Hydroxytyrosol is considered to be a powerful antioxidant in experimental studies. After virgin olive oil ingestion an increase of hydroxytyrosol, and also of 3-O-methyl-hydroxytyrosol, a compound derived from the hydroxytyrosol, in plasma and in urine was observed (See Figures 1 and 2). After 8 hours of virgin olive oil ingestion hydroxytyrosol values tended to return to basal values.

The results obtained show:

1. Hydroxytyrosol and tyrosol, can be absorbed in the human body from moderate, real-life doses of olive oil consumption. The administered dose, 25 mL, is close to the one used in Mediterranean countries.
2. Levels of phenolic compounds in plasma and in urine rise quickly and decrease during the 12 hours following virgin olive oil consumption. Thus, the best way to maintain a constant olive oil phenol concentration in the body, is the daily consumption of moderate and sustained doses of virgin olive oil.

Plasma hydroxytyrosol and 3-O-methyl hydroxytyrosol
levels after virgin olive oil ingestion

Urine hydroxytyrosol and 3-O-methyl hydroxytyrosol levels after virgin olive oil ingestion