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

Hypertension Clinical Trial

Official title:

Effect of Chronic Polyphenol-rich Olive Leaf Extract Intake on Cardiovascular Risk Markers

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01796561
• Other study ID #: OLE chronic study
• Status: Completed
• Phase: N/A
• First received: February 20, 2013
• Last updated: October 10, 2013
• Start date: February 2013
• Est. completion date: October 2013

Study information

• Verified date: October 2013
• Source: University of Reading
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Research Ethics Committee
• Study type: Interventional

Clinical Trial 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

Recruitment information / eligibility

• Status: Completed
• Enrollment: 60
• Est. completion date: October 2013
• Est. primary completion date: October 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 65 Years

Eligibility

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

Study Design

Allocation: Randomized, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Hypertension

Intervention

Dietary Supplement:
• Olive leaf extract liquid
Commercially available polyphenol-rich olive leaf extract liquid

Locations

Country	Name	City	State
New Zealand	Institute of Food, Nutrition and Human Health, Massey University	Albany, North Shore	Auckland

Sponsors (2)

Lead Sponsor	Collaborator
University of Reading	Massey University

Country where clinical trial is conducted

New Zealand, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Blood pressure measured via 24 hour ambulatory blood pressure monitors		6 weeks	No
Secondary	Vascular function assessed by pulse wave velocity (PWV)		6 weeks	No
Secondary	Lipid profile measured via serum assay		6 weeks	No
Secondary	Inflammatory cytokines measured via plasma assay		6 weeks	No
Secondary	Fructosamine measured via plasma assay		6 weeks	No
Secondary	Glucose measured via plasma assay		6 weeks	No
Secondary	Nitric oxide measured via plasma assay		6 weeks	No
Secondary	Insulin measured via plasma assay		6 weeks	No
Secondary	Haemostatic factors (D-dimer, PAI-1 ag, von Willebrand factor, prothrombin F1+2, factor VIII) measured via plasma assay		6 weeks	No
Secondary	Oxidised LDL measured via plasma assay		6 weeks	No
Secondary	Obesity markers (adiponectin, CCL-2, complement factor D, CRP, IL-6, IL-10, leptin, resistin, serpin E1 and TNF-a) measured via plasma assay		6 weeks	No