Pharmacol Res. 2010 Apr;61(4):364-70. Epub 2010 Jan 4.
Human absorption of a supplement containing purified hydroxytyrosol, a natural antioxidant from olive oil, and evidence for its transient association with low-density lipoproteins.
González-Santiago M, Fonollá J, Lopez-Huertas E.
Puleva Biotech S.A. 66, Camino de Purchil, Granada 18004, Spain.
Abstract
There is growing interest in the health effects of olive oil polyphenols, particularly hydroxytyrosol (HT), for their potential application in the treatment of inflammatory conditions such as cardiovascular disease (CVD). As oxidative modification of low-density lipoproteins (LDL) plays a central role in the development of CVD, natural antioxidants are a main target for the nutraceutical industry. In this study we firstly investigated the absorption of pure hydroxytyrosol (99.5%) administered as a supplement in an aqueous solution (2.5mg/kg BW) in the plasma and urine of healthy volunteers (n=10). Plasma C(max) for HT and homovanillic alcohol (HvOH) were detected at 13.0+/-1.5 and 16.7+/-2.4min, respectively. The HT and HvOH levels were undetectable 2-h after the administration. HT, HvOH, homovanillic acid and 3,4-dihydroxyphenylacetic acid were found as free forms (44%) or as glucuronide (34.4%) or sulphate (21.2%) conjugates in the 24-h urine samples of the subjects. In a second phase of the study, the same amounts of HT were administered to the subjects and the presence of HT in purified plasma lipoproteins was investigated in LDL fractions freshly isolated. 10min after the ingestion of the HT supplement, more than 50% of the total amount detected was present in the LDL-purified fractions and its concentration declined in accordance with its presence in plasma but no changes were found in total antioxidant capacity, malondialdehyde or LDL lag time. These results indicate that pure HT transiently associates with LDL lipoproteins in vivo. Copyright 2009 Elsevier Ltd. All rights reserved.
I haven't had time to comb through the references but there are some very good papers there regarding bioavailability of the phenols from sources (oil, aqueous, yoghurt).
FASEB J. 2010 Feb 23. [Epub ahead of print]
In vivo nutrigenomic effects of virgin olive oil polyphenols within the frame of the Mediterranean diet: a randomized controlled trial.
Konstantinidou V, Covas MI, Muñoz-Aguayo D, Khymenets O, de la Torre R, Saez G, Del Carmen Tormos M, Toledo E, Marti A, Ruiz-Gutiérrez V, Ruiz Mendez MV, Fito M.
*Cardiovascular Risk and Nutrition Research Group andHuman Pharmacology and Clinical Neurosciences Research Group, Institut Municipal d'Investigació Mèdica (IMIM-Hospital del Mar), Centro de Investigación Biomédica Eu |$$Red (CIBER) de Fisiopatología de la Obesidad y Nutrición, Barcelona, Spain;PhD Program in Biomedicine, Departament de Ciencies Experimentals i de la Salut, Pompeu Fabra University, Barcelona, Spain;Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain;||Department of Preventive Medicine and Public Health and paragraph signDepartment of Nutrition, Food Science, Physiology, and Toxicology, University of Navarra, Navarra, Spain; and#Instituto de Nutrition and Lipid Metabolism, Instituto de la Grasa, Seville, Spain.
Abstract
The aim of the study was to assess whether benefits associated with the traditional Mediterranean diet (TMD) and virgin olive oil (VOO) consumption could be mediated through changes in the expression of atherosclerosis-related genes. A randomized, parallel, controlled clinical trial in healthy volunteers (n=90) aged 20 to 50 yr was performed. Three-month intervention groups were as follows: 1) TMD with VOO (TMD+VOO), 2) TMD with washed virgin olive oil (TMD+WOO), and 3) control with participants' habitual diet. WOO was similar to VOO, but with a lower polyphenol content (55 vs. 328 mg/kg, respectively). TMD consumption decreased plasma oxidative and inflammatory status and the gene expression related with both inflammation [INF-gamma (INFgamma), Rho GTPase-activating protein15 (ARHGAP15), and interleukin-7 receptor (IL7R)] and oxidative stress [adrenergic beta2-receptor (ADRB2) and polymerase (DNA-directed) kappa (POLK)] in peripheral blood mononuclear cells. All effects, with the exception of the decrease in POLK expression, were particularly observed when VOO, rich in polyphenols, was present in the TMD dietary pattern. Our results indicate a significant role of olive oil polyphenols in the down-regulation of proatherogenic genes in the context of a TMD. In addition, the benefits associated with a TMD and olive oil polyphenol consumption on cardiovascular risk can be mediated through nutrigenomic effects.-Konstantinidou, V., Covas, M.-I., Muñoz-Aguayo, D., Khymenets, O., de la Torre, R., Saez, G., del Carmen Tormos, M., Toledo, E., Marti, A., Ruiz-Gutiérrez, V., Ruiz Mendez, M. V., Fito, M. In vivo nutrigenomic effects of virgin olive oil polyphenols within the frame of the Mediterranean diet: a randomized controlled trial.
PMID: 20179144 [PubMed - as supplied by publisher]
J Nutr. 2001 Jul;131(7):1993-6.
The in vivo fate of hydroxytyrosol and tyrosol, antioxidant phenolic constituents of olive oil, after intravenous and oral dosing of labeled compounds to rats.
Tuck KL, Freeman MP, Hayball PJ, Stretch GL, Stupans I.
Centre for Pharmaceutical Research, School of Pharmaceutical, Molecular and Biomedical Sciences, University of South Australia, Adelaide, 5000, Australia. kellie.tuck@unisa.edu.au
Abstract
In vitro studies have shown phenolics in olive oil to be strong radical scavengers. The absorption and elimination of two radiolabeled phenolic constituents of olive oil, hydroxytyrosol and tyrosol were studied in vivo using rats. Compounds were administered intravenously (in saline) and orally (in oil- and water-based solutions). For both compounds, the intravenously and orally administered oil-based dosings resulted in significantly greater elimination of the phenolics in urine within 24 h than the oral, aqueous dosing method. There was no significant difference in the amount of phenolic compounds eliminated in urine between the intravenous dosing method and the oral oil-based dosing method for either tyrosol or hydroxytyrosol. Oral bioavailability estimates of hydroxytyrosol when administered in an olive oil solution and when dosed as an aqueous solution were 99% and 75%, respectively. Oral bioavailability estimates of tyrosol, when orally administered in an olive oil solution and when dosed as an aqueous solution were 98% and 71%, respectively. This is the first study that has used a radiolabeled compound to study the in vivo biological fates of hydroxytyrosol and tyrosol.
PMID: 11435519 [PubMed - indexed for MEDLINE]
Anyways Skot turned me onto tyrosol and oleuperin and I've been doing a bit of reading on it. To me it seems so far the oil based is better absorbed and also olive oil has other benefits beyond tyosol so why supplement with it. I also remember reading that dairy may help with absorption (don't quote me, I'll try and find the study).
Also if anyone has access to this study it would be much appreciated:
Infect Disord Drug Targets. 2009 Aug;9(4):400-14.
Relevance of nutritional antioxidants in metabolic syndrome, ageing and cancer: potential for therapeutic targeting.Soory M.
PMID: 19689382 [PubMed - indexed for MEDLINE]