A Double-Blind, Cross-Over, Placebo-Controlled Study Evaluating the Effect of Quercetin 500 mg Tablets on Blood Uric Acid in Healthy Males

Effect of Quercetin Supplements on Healthy Males: a Four-Week Randomized Cross-Over Trial


Lead sponsor: University of Leeds

Source University of Leeds
Brief Summary

The purpose of this study was to test the effect of chronic consumption of Quercetin 500 mg tablets on blood uric acid and other biomarkers in adult males.

Detailed Description

The main goal of the research is to determine the long term effects of daily supplementation of quercetin, a compound naturally and normally present in food, on the chemical composition (uric acid ii and glucose) of blood and urine and on blood pressure, of healthy males.

Six of the volunteers will collect urine after consuming a standard meal made from fresh onion and after quercetin supplement intake, in the same way, with 3 days washout before each. The urine collected here will be analysed to check that the supplement is equivalent to the food. Stage 2 will only be conducted with supplement and placebo.

Healthy male volunteers with higher (than average) blood uric acid will be selected and will be asked to consume a standard supplement/placebo added to their own diet for 4 weeks per phase. Two arms are separated by 4 weeks resting period: quercetin supplement and placebo. Blood and urine samples will be taken every other week to detect any changes of uric acid and other biomarkers.

----- i) Quercetin is found in a variety of foods including apples, berries, brassica vegetables, capers, grapes, onions, shallots, tea, and tomatoes, as well as many seeds, nuts, flowers, barks, and leaves.

ii) Uric acid, a compound found in both in the human body and urine, is produced by the breakdown of purines, which are nitrogen-containing compounds in substances such as nucleic acids (DNA). They enter the circulation from digestion of certain foods, drinks (alcoholic beverages like beer and wine) or from normal breakdown and turnover of cells in the body. Most uric acid is removed by the kidneys and disposed of in the urine; the remainder is excreted in the stool.

Overall Status Completed
Start Date February 2013
Completion Date November 2014
Primary Completion Date April 2014
Phase Early Phase 1
Study Type Interventional
Primary Outcome
Measure Time Frame
Risk of getting hyperuricemia assessed by the measure of plasma uric acid. Fasting blood samples are taken on day 1, day 15 and day 29 of each arm
Secondary Outcome
Measure Time Frame
Kidney excretion of uric acid: urinary uric acid level 24 h urine samples are collected on day 14 and 28 of each arm and volume is recorded
Blood pressure Blood pressure is measured on day 1 and 29 of each arm
Blood glucose Fasted blood samples are collected on day 1, 15, 29 of each arm
Metabolomic and metabonomic profiling of blood plasma Fasting blood samples are taken on day 1, day 15 and day 29 of each arm
Enrollment 22

Intervention type: Dietary Supplement

Intervention name: Treatment

Description: Address: Nature's Best, Century Place, Tunbridge Wells, Kent, TN2 3BE Phone:+44(0)1892 552030 Email:[email protected]

Arm group label: Treatment

Intervention type: Dietary Supplement

Intervention name: Control

Description: Address: Fagron GmbH&Co. KG, 22885 Barsbuttel, Germany Phone: +49(0)4067067680

Arm group label: Placebo



Inclusion Criteria:

- Written informed consent

- Plasma Uric Acid > 300 micro Mole/L

- Generally Healthy

Exclusion Criteria:

- Body Mass Index (BMI) ≥ 30 kg/m² or <18.5 kg/m²

- Unable or unwilling to comply with the protocol, or likely to leave the study before its completion.

- Who would undertake important change in physical exercise or vigorous sport competitions during the study period.

- regularly drink more than 3 units of alcohol every day

- smokers

- have history of treated hyperuricemia, gout and/ or kidney stone

- have intestinal disorders

Gender: Male

Minimum age: 19 Years

Maximum age: 65 Years

Healthy volunteers: Accepts Healthy Volunteers

Overall Official
facility School of Food Science and Nutrition
Location Countries

United Kingdom

Verification Date

March 2015

Responsible Party

Responsible party type: Principal Investigator

Investigator affiliation: University of Leeds

Investigator full name: Yuanlu Shi

Investigator title: PhD Candidate

Has Expanded Access No
Condition Browse
Number Of Arms 2
Arm Group

Arm group label: Treatment

Arm group type: Experimental

Description: Daily intake of Quercetin supplement 500mg tablet for 28 days with meal (breakfast preferred.)

Arm group label: Placebo

Arm group type: Placebo Comparator

Description: Daily intake of Placebo (lactose) tablet for 28 days with meal (breakfast preferred)

Study Design Info

Allocation: Randomized

Intervention model: Crossover Assignment

Primary purpose: Basic Science

Masking: Double (Participant, Investigator)

Source: ClinicalTrials.gov