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Effects of Green Tea on Level of Serum Uric Acid in Healthy Individuals

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ClinicalTrials.gov Identifier: NCT01363869
Recruitment Status : Completed
First Posted : June 2, 2011
Last Update Posted : April 25, 2013
Sponsor:
Information provided by (Responsible Party):
Kanon Jatuworapruk, Chiang Mai University

Tracking Information
First Submitted Date  ICMJE May 31, 2011
First Posted Date  ICMJE June 2, 2011
Last Update Posted Date April 25, 2013
Study Start Date  ICMJE June 2011
Actual Primary Completion Date September 2012   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: May 31, 2011)
serum uric acid [ Time Frame: 4 weeks (prior to, immediately after and 7 days after intervention) ]
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: April 23, 2013)
  • urinary uric acid excretion [ Time Frame: 4 weeks (prior to, immediately after and 7 days after intervention) ]
  • serum antioxidant activity [ Time Frame: 4 weeks (prior to, immediately after and 7 days after intervention) ]
  • serum EGCG level [ Time Frame: 1 week (immediately after and 7 days after intervention) ]
    Measurements of serum level of epigallocatechin gallate (EGCG)
  • Adverse events [ Time Frame: 4 week (prior to, immediately after and 7 days after intervention) ]
    Adverse events during 4-week study
Original Secondary Outcome Measures  ICMJE
 (submitted: May 31, 2011)
  • urinary uric acid excretion [ Time Frame: 4 weeks (prior to, immediately after and 7 days after intervention) ]
  • serum antioxidant activity [ Time Frame: 4 weeks (prior to, immediately after and 7 days after intervention) ]
  • serum Catechins level [ Time Frame: 1 week (immediately after and 7 days after intervention) ]
    Measurements include serum level of Total catechins, catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG)
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Effects of Green Tea on Level of Serum Uric Acid in Healthy Individuals
Official Title  ICMJE Effects of Green Tea on Level of Serum Uric Acid in Healthy Individuals
Brief Summary Green tea has been extensively investigated for several potential health benefits. Previous studies have suggested that green tea may lower serum uric acid level in human. The purpose of this study is to investigate uric-lowering properties of green tea in healthy individuals.
Detailed Description

Elevated serum uric acid is related to the risk of development of gout, the most common inflammatory arthritis in men. Allopurinol, a xanthine oxidase inhibitor, is one of the uric-lowering agents commonly used in patients suffering from recurrent and chronic gout. Nevertheless, its use is limited by adverse effects and serious allergic reaction in some patients.

Green tea is one of the most frequently consumed beverages, particularly in Japan. Green tea contains high level of catechins, in which Epigallocatechin gallate (EGCG) is the most abundant compound among other types of catechins. Antioxidant effect contributes to various potential health benefits of green tea. Several in-vitro studies have found that green tea inhibits xanthine oxidase activity and subsequently decreases reactive oxygen species (ROS) and uric acid production. We therefore would like to investigate the hypouricemic effects of green tea.

The study consists of three periods with a total duration of four weeks. The first week is the control period. The following two weeks is the interventional period and the last week is the follow up period. Thirty healthy participants will be randomly assigned into three experimental groups, receiving 2 gm/day, 4 gm/day and 6 gm/day (in capsule, two times after meal) of green tea extract during interventional period. Blood and urine samples will be taken at the beginning and at the end of each study period.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Condition  ICMJE
  • Hyperuricemia
  • Gout
Intervention  ICMJE
  • Dietary Supplement: green tea extracts 2 gm/day

    Green tea extracts capsule (1 gm per capsule), taken after meal, twice daily for 14 days.

    Total dosage is 2 grams per day.

  • Dietary Supplement: green tea extracts 4 gm/day

    Green tea extracts capsule (1 gm per capsule), taken after meal, twice daily for 14 days.

    Total dosage is 4 grams per day.

  • Dietary Supplement: green tea extracts 6 gm/day

    Green tea extracts capsule (1 gm per capsule), taken after meal, twice daily for 14 days.

    Total dosage is 6 grams per day.

Study Arms  ICMJE
  • Experimental: Green tea extracts 2 gm/day
    Green tea extracts 2 gm/day for 14 days
    Intervention: Dietary Supplement: green tea extracts 2 gm/day
  • Experimental: Green tea extracts 4 gm/day
    Green tea extracts 4 gm/day for 14 days
    Intervention: Dietary Supplement: green tea extracts 4 gm/day
  • Experimental: Green tea extracts 6 gm/day
    Green tea extracts 6 gm/day for 14 days
    Intervention: Dietary Supplement: green tea extracts 6 gm/day
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: May 31, 2011)
30
Original Estimated Enrollment  ICMJE Same as current
Actual Study Completion Date  ICMJE March 2013
Actual Primary Completion Date September 2012   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Age 18 years or older
  • Healthy individuals
  • Normal renal and liver function from blood tests

Exclusion Criteria:

  • Presence of co-morbidity or currently ill
  • Currently using any medication or nutritional supplement product that may affect serum uric acid level
  • Serum creatinine higher than 1.5 mg/dl
  • Abnormal serum Aspartate aminotransferase (AST) and/or Alanine transaminase (ALT)
  • Greater than 15% change in serum uric acid during control period
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Thailand
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT01363869
Other Study ID Numbers  ICMJE MED-11-02-07-13-X
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party Kanon Jatuworapruk, Chiang Mai University
Study Sponsor  ICMJE Chiang Mai University
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Kanon Jatuworapruk, M.D Department of Internal medicine, Faculty of Medicine, Chiang Mai University, Thailand
PRS Account Chiang Mai University
Verification Date April 2013

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP