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

Gout Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01363869
• Other study ID #: MED-11-02-07-13-X
• Status: Completed
• Phase: N/A
• First received: May 31, 2011
• Last updated: April 23, 2013
• Start date: June 2011
• Est. completion date: March 2013

Study information

• Verified date: April 2013
• Source: Chiang Mai University
• Contact: n/a
• Is FDA regulated: No
• Health authority: Research Ethics Committee, Faculty of Medicine, Chiang Mai University, Thailand:
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: March 2013
• Est. primary completion date: September 2012
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years and older

Eligibility

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

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Gout
• Hyperuricemia

Intervention

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.
• 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.
• 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.

Locations

Country	Name	City	State
Thailand	Department of Internal Medicine, Faculty of Medicine, Chiang Mai University	Chiang Mai

Sponsors (1)

Lead Sponsor	Collaborator
Chiang Mai University

Country where clinical trial is conducted

Thailand, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	serum uric acid		4 weeks (prior to, immediately after and 7 days after intervention)	No
Secondary	urinary uric acid excretion		4 weeks (prior to, immediately after and 7 days after intervention)	No
Secondary	serum antioxidant activity		4 weeks (prior to, immediately after and 7 days after intervention)	No
Secondary	serum EGCG level	Measurements of serum level of epigallocatechin gallate (EGCG)	1 week (immediately after and 7 days after intervention)	No
Secondary	Adverse events	Adverse events during 4-week study	4 week (prior to, immediately after and 7 days after intervention)	Yes