Bioavailability of Hydroxytyrosol From Olive Watery Extract Supplements
Condition: Biological Availability
Study type: Interventional

Summary: 
      The aim of this cross-over study is to assess the bioavailability of hydroxytyrosol in
      healthy males after the intake of two olive watery extract supplements and one olive oil.
      Blood and urine samples will be collected before and after intake of the investigational
      products. Sample will be analysed regarding the level of hydroxytyrosol and preventing lipid
      peroxidation.
    

Detailed description: 
      Background:

      Hydroxytyrosol is a phenolic phytochemical naturally occurring in olives with potential
      antioxidant, anti-inflammatory, and health benefits mainly related with cardiovascular
      diseases [for review see Covas et al., 2015]. OliPhenolia® bitter and OliPhenolia® are two
      food supplements resulting from the liquid by-product generated during olive oil production,
      that are rich in olive polyphenols, mainly hydroxytyrosol. Hydroxytyrosol and its derivatives
      (tyrosol and oleuropein) are present in higher levels in the watery extracts from olives when
      compared with the oil fraction.

      Most studies on hydroxytyrosol bioavailability have been performed by consuming it with olive
      oil or as a highly purified molecule. In a study by D'Angelo and collaborators [D'Angelo et
      al, 2001] it was shown that hydroxytyrosol can be rapidly absorbed from the blood and
      distributed in the human body, metabolized and eliminated rapidly in urine mainly as a
      glucuronide. It has been estimated that the absorption process depends on the composition of
      the food matrix through which hydroxytyrosol is administered [Visioli et al, 2003], when
      consumed together with fats (e.g. olive oil) it is absorbed in a greater extent. By being a
      water-soluble molecule, hydroxytyrosol is only slightly soluble in fats, therefore naturally
      present in significantly higher concentrations in the olive fruit aqueous fractions than in
      the olive oil.

      Overall, the human studies support the need to evaluate the bioavailability of hydroxytyrosol
      following its administration as a major component of the two aqueous food supplements,
      OliPhenolia® and OliPhenolia® bitter.

      Study Procedure:

      After detailed information and signed informed consent all males meeting the inclusion and
      exclusion criteria will be included into the study. During their study participation,
      participants are not allowed to consume any products with or made from olives or olive oil as
      well as alcohol and supplements with hydroxytyrosol, vitamins, minerals and antioxidants.
      Products high in polyphenols and antioxidants may only be consumed in moderate amounts. Three
      days prior to and at each intervention day, volunteers will be requested to avoid moderate or
      intense physical activity.

      After a run-in period, participants will return in a fasted state to the site for the first
      intervention visit. Volunteers will be asked to empty their bladder at home 2h before IP
      intake. After arriving at the site, a baseline blood and urine sample (-5 min) will be
      collected and the participants receive according to the individual allocation determining the
      sequence of the IP intake either one of the olive watery extract supplements (OliPhenolia®
      bitter or OliPhenolia®) or the olive oil first. Further blood and urine samples will follow
      (+30 min, +60 min, +90 min, +120 min, +240 min, +12 h). Vital signs and AEs will be checked
      throughout the intervention visit. Participants will receive several snacks and water during
      their visit.

      After a one-week washout phase each, participants will return to their second and third
      intervention visit. The same procedures as on intervention visit 1 will take place except the
      IP intake will vary according to the individual allocation.

      At the end of the third intervention visit, participants will receive a study compensation.
    

Intervention name(s): Oliphenolia® bitter; Oliphenolia®; La Vialla Extra Virgin Olive Oil containing 5 mg hydroxytyrosol
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): ingredients: concentrated watery extract of olives 94%, lemon juice 6%
35 mg hydroxytyrosol, 0,24 mg Oleuropein; ingredients: grape juice concentrate 70%, concentrated watery extract of olives 30%
38 mg hydroxytyrosol, 0,28 mg Oleuropein; extra virgin olive oil
5 mg hydroxytyrosol
Intervention MeSH terms: 3,4-dihydroxyphenylethanol
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Three-armed study with a cross-over design. Participants will be randomly assigned to either group A, B or C. The group allocation will define the sequence of product intake:
Group A: first OliPhenolia® bitter, second OliPhenolia®, third La Vialla Extra Virgin Olive Oil
Group B: first OliPhenolia®, second La Vialla Extra Virgin Olive Oil, third OliPhenolia® bitter
Group C: first La Vialla Extra Virgin Olive Oil, second OliPhenolia® bitter, third OliPhenolia®
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Olives