Effect of Olive Leaves as Hypoglycemic Agents in Diabetic Subjects

A Phase Three Clinical Intervention Trial of Olive Leaves and Their Extracts in Human Diabetic Subjects

Background: Animal studies indicate that olive leaf extract normalizes blood glucose. We hypothesized that olive leaf extract might be of benefit in human subjects.

Methods: A total of 79 adults with diabetes were randomly assigned to treatment with olive leaf extract capsules or matched placebo. Measures of glucose homeostasis including glucose, insulin and HbA1c were measured and compared by treatment group.

Study Overview

• Status: Completed
• Conditions: Diabetes
• Intervention / Treatment: Other: placebo; Dietary supplement: olive leaf extract

Detailed Description

The present study is a randomized, double blind, placebo controlled, clinical trial with a 14 week duration. Patients were randomized to treatment with a tablet of olive leaves or matching placebo in 1:1 ratio.

Patients were instructed to consume a diet consistent with ADA recommendations and an exercise training program was prescribed.

Weight, height, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in all subjects at the beginning and at the end of the study. Venous blood samples were drawn after an overnight fast of not less than 12 hours. Laboratory tests included fasting blood glucose (FBG), HbA1c, insulin, lipid panel and liver and renal function.

A total of 79 subjects (51 men, 28 women) aged 18-79 years with type 2 diabetes mellitus, were recruited from and followed up at an outpatient clinic. The subjects were selected from a series of 93 consecutive diabetic patients. Eligible patients had been diagnosed with T2DM for at least 1 year.

Subjects were randomized to treatment with olive leaf extract pills (1 500 mg pill daily taken orally) or matching placebo. The intervention was prepared as follows: olive leaves were picked from the Barnea cultivar in the Jezreel Valley region of Israel and immediately freeze-dried on dry ice. After the leaves were thoroughly rinsed with sterile distilled water to remove dust, insecticides, and contaminating material, the leaves were ground and successively Soxhlet extracted with hexane for 3 h and 80% aqueous ethanol for 6 h. The alcoholic extract was concentrated under reduced pressure at 25 °C, and reconstituted with 30% ethanol in water.

Olive leaves or placebo tablet was taken once daily orally throughout the study. All subjects continue their stable treatment to diabetes.

Data were analyzed using SPSS v10.0 (SPSS Inc., Chicago, USA). Continuous data were described a mean ± standard deviation and compared by treatment assignment using the t-test for independent samples. Associations between continuous variables were described by calculating the Pearson's correlation coefficients. Nominal variables such as sex and treatment assignment are described using frequency counts and compared by treatment assignment using the chi square test (exact as appropriate). All tests are two-sided and considered significant at p<0.05.

• Study Type: Interventional
• Enrollment (Actual): 79
• Phase: Phase 3

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 78 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• adults
• type 2 diabetes

Exclusion Criteria:

• type 1 diabetes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: placebo; matched placebo	Other: placebo; placebo
Active Comparator: olive leaf extract; Olive leaf polyphenol concentrate (OLPC) extraction OLPC was prepared from olive leaves as follows (Zaslave et al, 2005) : The leaves were randomly picked from the Barnea cultivar in the Jezreel Valley region of Israel and immediately freeze-dried on dry ice. After the leaves were thoroughly rinsed with sterile distilled water to remove dust, insecticides, and contaminating material, the leaves were ground and successively Soxhlet extracted with hexane for 3 h and 80% aqueous ethanol for 6 h. The alcoholic extract was concentrated under reduced pressure at 25 °C, and reconstituted with 30% ethanol in water.	Dietary supplement: olive leaf extract; olive leaf extract, 1 pill daily, 500 mg, for a duration of 14 wks; Other Names: Olife

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum glucose	serum glucose	14 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma insulin	Plasma insulin	14 weeks

Collaborators and Investigators

• Sponsor: Wolfson Medical Center
• Investigators: Principal Investigator: Julio Wainstein, MD, E. Wolfson Medical Center

Study record dates

Study Major Dates

• Study Start: August 1, 1999
• Primary Completion (Actual): August 1, 2001
• Study Completion (Actual): August 1, 2001

Study Registration Dates

• First Submitted: August 3, 2011
• First Submitted That Met QC Criteria: September 1, 2011
• First Posted (Estimate): September 2, 2011

Study Record Updates

• Last Update Posted (Estimate): September 2, 2011
• Last Update Submitted That Met QC Criteria: September 1, 2011
• Last Verified: September 1, 2011

More Information

Terms related to this study

• Keywords: diabetes; blood glucose; olive leaf extract
• Other Study ID Numbers: WMC1111