Tyrosol and hydroxytyrosol are absorbed from moderate and sustained doses of virgin olive oil in humans

Objective: To investigate the absorption of tyrosol and hydroxytyrosol from moderate and sustained doses of virgin olive oil consumption. The study also aimed to investigate whether these phenolic compounds could be used as biomarkers of virgin olive oil intake. Design and interventions: Ingestion of a single dose of virgin olive oil (50 ml). Thereafter, for a week, participants followed their usual diet which included 25 ml/day of the same virgin olive oil as the source of raw fat. Setting: Unitat de Recerca en Farmacologia. Institut Municipal d'Investigacio Medica (IMIM). Subjects: Seven healthy volunteers. Results: An increase in 24h urine of tyrosol and hydroxytyrosol, after both a single-dose ingestion (50 ml) and short-term consumption (one week, 25 ml/day) of virgin olive oil (P < 0.05) was observed. Urinary recoveries for tyrosol were similar after a single dose and after sustained doses of virgin olive oil. Mean recovery values for hydroxytyrosol after sustained doses were 1.5-fold those obtained after a single 50 ml dose. Conclusions: Tyrosol and hydroxytyrosol are absorbed from realistic doses of virgin olive oil. With regard to the dose-effect relationship, 24 h urinary tyrosol seems to be a better biomarker of sustained and moderate doses of virgin olive oil consumption than hydroxytyrosol. Sponsorship: This work was supported by grants AL197-1607-CO2-01 from CICYT, 98/9562 FPI from FIS and by Federacio de Cooperatives Agraries de Catalunya.