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

NCT ID: NCT01796561

Last Updated: 2013-10-11

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2013-02-28
• Study Completion Date: 2013-10-31

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

Conditions

Hypertension

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: QUADRUPLE

Study Groups

Olive leaf extract liquid

20ml of polyphenol-rich olive leaf extract liquid to be consumed daily for 6 weeks

Group Type: ACTIVE_COMPARATOR

Olive leaf extract liquid

Intervention Type: DIETARY_SUPPLEMENT

Commercially available polyphenol-rich olive leaf extract liquid

Placebo liquid

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

Group Type: PLACEBO_COMPARATOR

No interventions assigned to this group

Interventions

Olive leaf extract liquid

Commercially available polyphenol-rich olive leaf extract liquid

Intervention Type: DIETARY_SUPPLEMENT

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Massey University

OTHER

Sponsor Role: collaborator

University of Reading

OTHER

Sponsor Role: lead

Responsible Party

Jeremy Paul Edward Spencer

Professor of Biochemistry

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Welma Stonehouse, PhD

Role: PRINCIPAL_INVESTIGATOR

Massey University

Locations

Institute of Food, Nutrition and Human Health, Massey University

Albany, North Shore, Auckland, New Zealand

Countries

New Zealand

Other Identifiers

OLE chronic study

Identifier Type: -

Identifier Source: org_study_id