Clinical trial NCT01881919: Effect of Quercetin Supplements on Healthy Males: a Four-Week Randomized Cross-Over Trial
Official title: A Double-Blind, Cross-Over, Placebo-Controlled Study Evaluating the Effect of Quercetin 500 mg Tablets on Blood Uric Acid in Healthy Males
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: EARLY_PHASE1
Conditions: Hyperuricemia
Gout
Kidney Calculi
Diabetes
Cardiovascular Disease
Keywords: Functional Food
Lead sponsor: University of Leeds
Sponsor class: OTHER
First posted: 2013-06-20
Enrollment: 22
Sex: MALE
Minimum age (years): 19
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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

Primary outcomes:
measure: Risk of getting hyperuricemia assessed by the measure of plasma uric acid.
timeFrame: Fasting blood samples are taken on day 1, day 15 and day 29 of each arm
Secondary outcomes:
measure: Kidney excretion of uric acid: urinary uric acid level
timeFrame: 24 h urine samples are collected on day 14 and 28 of each arm and volume is recorded
measure: Blood pressure
timeFrame: Blood pressure is measured on day 1 and 29 of each arm
measure: Blood glucose
timeFrame: Fasted blood samples are collected on day 1, 15, 29 of each arm
measure: Metabolomic and metabonomic profiling of blood plasma
timeFrame: Fasting blood samples are taken on day 1, day 15 and day 29 of each arm
Other outcomes:
measure: Urinary excretion of quercetin
timeFrame: 24 h urine will be collected on day 14 and 28 of each arm and volume is recorded
measure: Subject Body Weight
timeFrame: weight is measured on day 1 and 29 of each arm
measure: Subject Height
timeFrame: Height is measured on day 1 and 29 of each arm
measure: Life style maintenance
timeFrame: Recall Questionnaires about the past 28 days are required on day 1 and 29 of each arm.
measure: Primary health assessment
timeFrame: Recall Questionnaires about history of certain disease, routine medication / supplements, allergies and exercise/diet practice at enrollment
Locations:
city: Leeds
country: United Kingdom
facility: School of Food Science and Nutrition
state: West Yorkshire
Study officials:
affiliation: University of Leeds
name: Gary Williamson, PhD
role: STUDY_CHAIR
affiliation: University ofLeeds
name: Yuanlu Shi, PhD Candidate
role: PRINCIPAL_INVESTIGATOR
References: