Gout, Hyperuricemia
Conditions
Keywords
hyperuricemia, gout, uric acid, xanthine oxidase inhibitor, green tea, catechins, antioxidant
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.
Interventions
DIETARY_SUPPLEMENTgreen 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_SUPPLEMENTgreen 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_SUPPLEMENTgreen 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.
Sponsors
Chiang Mai University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| serum uric acid | 4 weeks (prior to, immediately after and 7 days after intervention) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| urinary uric acid excretion | 4 weeks (prior to, immediately after and 7 days after intervention) | — |
| serum antioxidant activity | 4 weeks (prior to, immediately after and 7 days after intervention) | — |
| serum EGCG level | 1 week (immediately after and 7 days after intervention) | Measurements of serum level of epigallocatechin gallate (EGCG) |
| Adverse events | 4 week (prior to, immediately after and 7 days after intervention) | Adverse events during 4-week study |
Countries
Thailand
Outcome results
None listed