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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Hyperuricemia, Gout, Kidney Calculi, Diabetes, Cardiovascular Disease

Intervention / Treatment
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* Dietary Supplement: Treatment
* Dietary Supplement: Control


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Treatment<br>Daily intake of Quercetin supplement 500mg tablet for 28 days with meal (breakfast preferred.) | Dietary Supplement: Treatment<br>* Address: Nature's Best, Century Place, Tunbridge Wells, Kent, TN2 3BE Phone:+44(0)1892 552030 Email:info@naturesbest.co.uk<br>* Other names: Serial Number: 5055148404901;|
| Placebo Comparator: Placebo<br>Daily intake of Placebo (lactose) tablet for 28 days with meal (breakfast preferred) | Dietary Supplement: Control<br>* Address: Fagron GmbH&Co. KG, 22885 Barsbuttel, Germany Phone: +49(0)4067067680<br>* Other names: Batch Number:1208D001A;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Risk of getting hyperuricemia assessed by the measure of plasma uric acid. | The change of plasma uric acid level from day 1 on day 15 and day 29 of each arm. | Fasting blood samples are taken on day 1, day 15 and day 29 of each arm | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Kidney excretion of uric acid: urinary uric acid level | Difference in 24-h urinary uric acid level at 14 days and 28 days between arms | 24 h urine samples are collected on day 14 and 28 of each arm and volume is recorded | 
| Blood pressure | To monitor the compliance of subject. | Blood pressure is measured on day 1 and 29 of each arm | 
| Blood glucose | The change of plasma glucose level from the baseline at day 15 and day 29 of each arm. | Fasted blood samples are collected on day 1, 15, 29 of each arm | 
| Metabolomic and metabonomic profiling of blood plasma | 1H NMR (proton nuclear magnetic resonance ) | Fasting blood samples are taken on day 1, day 15 and day 29 of each arm | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Functional Food