title: Hydroxytyrosol supplementation increases vitamin C levels in vivo. A human volunteer trial.
abstract: Hydroxytyrosol (HT) is a main phenolic component of olive oil. In this study, we investigated the safety and effects produced by HT purified (99.5%) from olive mill waste. HT was administered at a daily dosage of 45mg for 8 weeks to volunteers with mild hyperlipidemia (n=14). We measured markers of cardiovascular disease risk, enzyme markers of several clinical conditions, hematology, antioxidant parameters, vitamins and minerals at baseline (T0), 4 weeks (T4) and 8 weeks (T8). The values obtained at T4 and T8 were compared with baseline. We found that the HT dose administered was safe and mostly did not influence markers of cardiovascular disease, blood lipids, inflammatory markers, liver or kidney functions and the electrolyte balance. Serum iron levels remained constant but a significant (P<0.05) decrease in ferritin at T4 and T8 was found. Serum folate and red blood cell folate levels were also reduced at T4 and T8. Finally, vitamin C increased by two-fold at T4 and T8 compared with levels at baseline. These results indicate a physiologically relevant antioxidant function for HT through increasing endogenous vitamin C levels.
authors.affiliation: Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), 1, Profesor Albareda, Granada 18008, Spain. Electronic address: eduardo.lopezhuertas@eez.csic.es.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lopez-Huertas
authors.affiliation: BIOSEARCH LIFE S.A. 66, Camino de Purchil, Granada 18004, Spain.
authors.forename: Juristo
authors.initials: J
authors.lastname: Fonolla
mesh_terms: D000328:Adult; D001205:Ascorbic Acid / Q000819:agonists* / Q000097:blood; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000097:blood; D064368:Healthy Volunteers; D006801:Humans; D007501:Iron / Q000097:blood; D007677:Kidney Function Tests; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008111:Liver Function Tests; D008297:Male; D000069463:Olive Oil / Q000737:chemistry*; D010626:Phenylethyl Alcohol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000302:isolation & purification
chemical_list: D008055:Lipids; D000069463:Olive Oil; C005975:3,4-dihydroxyphenylethanol; D005492:Folic Acid; D007501:Iron; D010626:Phenylethyl Alcohol; D001205:Ascorbic Acid
keywords: Antioxidant; Human study; Hydroxytyrosol; Olive oil; Polyphenolics; Vitamin c