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Effect of an Extract of Green Tea on Adults With Type 2 Diabetes

This study has been completed.
Information provided by:
Dartmouth-Hitchcock Medical Center Identifier:
First received: October 16, 2006
Last updated: October 17, 2006
Last verified: October 2006
The objective of this study was to determine if taking an extract of green tea for three months could improve glucose control in adults with diabetes.

Condition Intervention Phase
Diabetes Drug: Extract of Green and Black Tea Phase 2 Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double
Primary Purpose: Treatment
Official Title: The Effect of an Extract of Green Tea on Glucose Control in Adults With Type 2 Diabetes

Resource links provided by NLM:

Further study details as provided by Dartmouth-Hitchcock Medical Center:

Primary Outcome Measures:
  • HbA1c

Estimated Enrollment: 48
Study Start Date: August 2005
Estimated Study Completion Date: June 2006
Detailed Description:

Background: Recent evidence suggests that tea from Camellia Senensis (e.g., green, oolong and black tea) may have a hypoglycemic effect.

Objective: We evaluated the ability of an extract of green and black tea to improve glucose control over a three month period using a double blinded randomized multiple dose (either placebo, 375mg or 750mg) study in adults in with Type 2 Diabetes.

Patients: The 49 subjects who completed this study were predominantly whites with an average age of 65, a median duration of Diabetes of 6 years, and 80% reported using hypoglycemic medication.

Measurements: HbA1c at three months was the primary endpoint. Results: After three months the mean changes in HbA1c were +0.4, +0.3 and +0.5, in the placebo, 375mg and 750mg arms, respectively. The changes were not significantly different between study arms.

Limitations: Evaluation of a particular extract that contained components of black teas as well as green tea. Power insufficient to detect changes in HbA1c < 0.5.

Conclusions: We did not find a hypoglycemic effect of extract of green tea in adults with Type 2 Diabetes, but cannot rule out the possibility that tea may have a small beneficial effect.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Adults with Diabetes not taking insulin

Exclusion Criteria:

  • pregnancy, warfarin therapy
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Please refer to this study by its identifier: NCT00389350

United States, New Hampshire
Dartmouth-Hitchcock Medical Center
Lebanon, New Hampshire, United States, 03756
Sponsors and Collaborators
Dartmouth-Hitchcock Medical Center
Principal Investigator: Todd A MacKenzie, PhD Dartmouth-Hitchcock Medical Center
  More Information Identifier: NCT00389350     History of Changes
Other Study ID Numbers: Hitchcock Tea 1
Study First Received: October 16, 2006
Last Updated: October 17, 2006

Additional relevant MeSH terms:
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases processed this record on August 18, 2017