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The Effect of Olive Leaf Extract on Blood Pressure in Overweight Prehypertensives

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ClinicalTrials.gov Identifier: NCT01796561
Recruitment Status : Completed
First Posted : February 21, 2013
Last Update Posted : October 11, 2013
Massey University
Information provided by (Responsible Party):
Jeremy Paul Edward Spencer, University of Reading

Brief Summary:

Cardiovascular disease (CVD) is the leading cause of death in New Zealand (40% of all deaths). 37% of New Zealanders suffer from high blood pressure (World Health Organisation 2008 figures), a well established modifiable risk factor for CVD. Above 115/75 mmHg, CVD risk doubles for each increment of 20/10 mmHg that blood pressure is raised. An increase in BMI and waist circumference has been associated with an increase in blood pressure. The leaves of the olive plant are rich in plant compounds known as polyphenols. This particular group of polyphenols are known secoiridoids, which are also present in olive oil and olives though at lower concentrations, are only found in this family of plants. Diets high in polyphenols have been found to reduce the risk of chronic diseases. Studies have shown that consumption of phenolic-rich olive leaf extract (OLE) can significantly reduce blood pressure in individuals suffering from high blood pressure (hypertension), with the magnitude of effect being comparable to a commonly used antihypertensive drug. In such trials OLE also resulted in an improved blood lipid (a reduction in total and LDL cholesterol and triacylglycerides) which also reduces CVD risk. One study testing the effect of OLE on individuals with mild or prehypertension (i.e. those with systolic blood pressure in the range 121-139 mmHg and diastolic blood pressure in the range 81-89 mmHg but not taking antihypertensive medication) also found these same improvements. OLE has been indicated to have the potential to improve other cardiovascular risk markers such as vascular function, inflammation, platelet aggregation, oxidation of LDL and glucose tolerance however much of this evidence is derived from animal, in vitro and ex vivo studies and so well designed and controlled human studies are required to verify that these findings are applicable to humans. Therefore OLE supplementation may be a useful dietary strategy for reducing CVD risk in a cohort of overweight prehypertensive individuals.

The aim of the study is to determine the effect of OLE intake on blood pressure and other CVD risk markers in overweight subjects with mild hypertension and to link any study outcomes with the presence of OLE phenolics in urine

Condition or disease Intervention/treatment Phase
Hypertension Dietary Supplement: Olive leaf extract liquid Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 60 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Effect of Chronic Polyphenol-rich Olive Leaf Extract Intake on Cardiovascular Risk Markers
Study Start Date : February 2013
Actual Primary Completion Date : October 2013
Actual Study Completion Date : October 2013

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: Olive leaf extract liquid
20ml of polyphenol-rich olive leaf extract liquid to be consumed daily for 6 weeks
Dietary Supplement: Olive leaf extract liquid
Commercially available polyphenol-rich olive leaf extract liquid

Placebo Comparator: Placebo liquid
20ml of polyphenol-free placebo liquid (containing water, glycerin, flavours, colours and aromas) to be consumed daily for 6 weeks

Primary Outcome Measures :
  1. Blood pressure measured via 24 hour ambulatory blood pressure monitors [ Time Frame: 6 weeks ]

Secondary Outcome Measures :
  1. Vascular function assessed by pulse wave velocity (PWV) [ Time Frame: 6 weeks ]
  2. Lipid profile measured via serum assay [ Time Frame: 6 weeks ]
  3. Inflammatory cytokines measured via plasma assay [ Time Frame: 6 weeks ]
  4. Fructosamine measured via plasma assay [ Time Frame: 6 weeks ]
  5. Glucose measured via plasma assay [ Time Frame: 6 weeks ]
  6. Nitric oxide measured via plasma assay [ Time Frame: 6 weeks ]
  7. Insulin measured via plasma assay [ Time Frame: 6 weeks ]
  8. Haemostatic factors (D-dimer, PAI-1 ag, von Willebrand factor, prothrombin F1+2, factor VIII) measured via plasma assay [ Time Frame: 6 weeks ]
  9. Oxidised LDL measured via plasma assay [ Time Frame: 6 weeks ]
  10. Obesity markers (adiponectin, CCL-2, complement factor D, CRP, IL-6, IL-10, leptin, resistin, serpin E1 and TNF-a) measured via plasma assay [ Time Frame: 6 weeks ]

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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

Men 18-65 years; Non-smokers; Prepared to consume olive leaf extract liquid Systolic blood pressure 121-139 mmHg and diastolic blood pressure 81-89 mmHg Body mass index (BMI) between 25-30 kg/m2 or waist >102 cm

Exclusion Criteria:

Smokers Using blood pressure, lipid lowering, thyroid disorder, blood clotting medication Using supplements or functional foods that will affect lipid concentrations (e.g. sterol enriched spreads) Chronic disease e.g. CHD, diabetes, cancer, digestive disorders Individuals who are unwilling to refrain from consuming olive containing products for the duration of the study

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01796561

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New Zealand
Institute of Food, Nutrition and Human Health, Massey University
Albany, North Shore, Auckland, New Zealand, 0745
Sponsors and Collaborators
University of Reading
Massey University
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Principal Investigator: Welma Stonehouse, PhD Massey University
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Responsible Party: Jeremy Paul Edward Spencer, Professor of Biochemistry, University of Reading
ClinicalTrials.gov Identifier: NCT01796561    
Other Study ID Numbers: OLE chronic study
First Posted: February 21, 2013    Key Record Dates
Last Update Posted: October 11, 2013
Last Verified: October 2013
Additional relevant MeSH terms:
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Vascular Diseases
Cardiovascular Diseases