Condition category
Circulatory System
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Prof Rosa Sola


Contact details

C/ Sant Llorenç

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effects of virgin olive oil enriched with phenolic compounds on blood pressure and endothelial function: a randomised double-blind crossover controlled trial


OLIPA study

Study hypothesis

Increased antioxidant capacity exerted by phenolic compounds improved endothelial function leading to reduced blood pressure in postprandial state.

Ethics approval

Local medical ethics committee (Comité d'Ètica d'Investigació Clínica Hospital Universitari Sant Joan, Reus) approved, 24/04/2008, ref: 08-04-24/4proj5

Study design

Randomised double-blind crossover controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Ischaemic reactive hyperaemia/blood pressure


All participants will follow a stabilisation period of 1 week with a low saturated fat diet. The day before to the postprandial test was followed by a polyphenol-free diet. Participants will be randomised individually between two postprandial tests:
1. Virgin olive oil. This will have a polyphenol content of 332.63 mg/kg (or 332.63 ppm measured by HPLC-DAD), an amount similar to oils in the area.
2. Virgin olive oil enriched with polyphenols. This will be enriched with polyphenols from defatted olive paste, which increase the concentrations up to three times, reaching a total content of 1008.14 mg/kg (or 1008.14 ppm measured by HPLC-DAD). These oils are prepared by the research group from Universitat de Lleida.

Participants will be provided with 80 g of bread containing 30 ml of the oil they have been allocated to. For 300 minutes after ingestion, participants will rest and may only drink water. One week later, participants will take the other investigational product in the same manner as before.

Diet monitoring will be conducted through a 3-day dietary record, in weeks 1 and 2. Participants are advised to maintain their usual physical activity and are monitored by a physical activity questionnaire.

Intervention type



Not Applicable

Drug names

Virgin olive oil enriched with phenolic compounds

Primary outcome measure

1. Blood pressure, measured at baseline and 120, 240 and 300 minutes on each study day
2. Endothelial function and activation biomarkers, measured at baseline and 120 , 240 and 300 minutes on each study day

Secondary outcome measures

Difference between the two oils (from baseline to 120, 240 and 300 minutes) of the following parameters:
1. The concentration of phenolic compounds in plasma, up to 300 minutes
2. Lipoproteins (total cholesterol, low density lipoprotein [LDL] cholesterol, high density lipoprotein [HDL] cholesterol, triglycerides) and apolipoproteins A1 and B100
3. Liver function tests
4. Angiotensin converting enzymes (ACE) inhibitory activity
5. Biomarkers of oxidation (LDL oxidised lipoperoxides, 8-epi-prostaglandin F2)
6. Biomarkers of inflammation (interleukin 6, high sensitivity C-reactive protein [hsCRP])
7. Antithrombotic activity biomarkers (plasminogen activator inhibitor-1 [PAI-1], factor VII antigen [FVIIag], activated factor VII [FVIIa])
8. Endothelial activation biomarkers (vascular cell adhesion molecules [VCAMs], intercellular adhesion molecules [ICAMs], e-selectin)
9. The relationship between nitrate (NO3)/nitrite (NO2)
10. Glycaemia and insulin resistance by Homeostatic Model Assessment (HOMA) index
11. The genetic profile of genes involved in endothelial function and blood pressure

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Healthy volunteers aged 18 to 75 years, either sex
2. Systolic blood pressure levels upper or equal 120 to 159 mmHg and/or diastolic blood pressure upper or equal 80 to 99 mmHg without antihypertensive treatment

Participant type

Healthy volunteer

Age group




Target number of participants

30 (15 men and 15 women)

Participant exclusion criteria

1. Low density lipoprotein cholesterol (LDL-c) levels upper 189 mg/dL
2. Triglycerides upper 350 mg/dL (the threshold level to determine LDL-c by the Friedewald formula)
3. Chronic alcoholism
4. Body mass index (BMI) upper 30 kg/m^2
5. Statin treatment prior to initiating the trial and would not have left at least 2 months before starting the study
6. Antihypertensive treatment prior to initiating the trial and would not have left at least 2 months before starting the study
7. Having diabetes mellitus (if you develop a blood glucose, fasting, upper 126 mg/dL, should be repeated and confirmed)
8. Renal disease (plasma creatinine levels upper 1.4 mg/dL for women and upper 1.5 mg/dL for men
9. Having acute infectious diseases, malignancies, severe liver insufficiency, chronic respiratory insufficiency or associated endocrine diseases
10. Other conditions such as special nutritional requirements or medications that may affect lipid metabolism or blood pressure
11. Participate or participating in a clinical trial in the last 3 months
12. Incapacity to continue in the study
13. History of gastrointestinal disease that can impair the absorption of nutrients
14. Suicide attempt

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

C/ Sant Llorenç, 21

Sponsor information


Rovira i Virgili University (Spain)

Sponsor details

Health Science Faculty
C/ Sant Llorenç

Sponsor type




Funder type


Funder name

Spanish Ministry of Education and Science (Spain) (ref: AGL2005-07881-C02-01/ALI)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2015 results in:

Publication citations

  1. Results

    Valls RM, Farràs M, Suárez M, Fernández-Castillejo S, Fitó M, Konstantinidou V, Fuentes F, López-Miranda J, Giralt M, Covas MI, Motilva MJ, Solà R, Effects of functional olive oil enriched with its own phenolic compounds on endothelial function in hypertensive patients. A randomised controlled trial., Food Chem, 2015, 167, 30-35, doi: 10.1016/j.foodchem.2014.06.107.

Additional files

Editorial Notes