Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Oranges are one of the most popular foods in the world and are commonly enjoyed as a fresh fruit and as a juice. They are a great source of many nutrients including polyphenolic compounds called flavanones. There is evidence to suggest that flavanones may be, in part, responsible for a potentially protective effect of orange juice against cardiovascular (heart) disease. Flavanones, like antioxidants, 'mop up' free radicals, molecules that damage blood vessels and cause arteries to become clogged up with cholesterol. Once drunk, the flavanones in orange juice are broken down into metabolites in the digestive system before they are then taken into the blood stream. It is, therefore, the effects of these metabolites that lead to the protective effects against cardiovascular disease (CD). The eventual aim is to understand how these metabolites work in the body, but here we are working towards identifying and quantifying those that are produced in the digestive system (namely the gastrointestinal tract) before they enter the bloodstream. In our previous work, we have looked at the appearance of flavonone metabolites in the blood after the drinking of some orange juice. This study will look at their excretion (removal from the body) in the urine 0-24 hours after the drinking of orange juice as this gives us a much better overall measure of how much has been absorbed.

Who can participate?
Healthy volunteers between 20 and 60 years old, non-smokers and not under medication.

What does the study involve?
Volunteers are required to follow a diet low in polyphenolic compounds for 48 hours before the start of the study and for 24 hours after supplementation, avoiding fruits, vegetables, high-fibre products, and drinks such as tea, coffee, fruit juice, and wine. Then, after an overnight fast, each person drinks 250 mL of pulp-enriched orange juice. A light breakfast of white bread, cheese, ham and milk is provided 2 hours after the orange juice has been drunk. Two weeks later, the volunteers drink 250 mL of a placebo drink. All urine is collected on five occasions over the periods 0, 0-2, 2-5, 5-10 and 10-24 hours after drinking either the orange juice or placebo drink.

What are the possible benefits and risks of participating?
There are no potential risks or benefits to taking part in the study.

Where is the study run from?
The University of Glasgow (UK)

When is the study starting and how long is it expected to run for?
January 2012 to December 2012

Who is funding the study?
The Coca-Cola Company (USA)

Who is the main contact?
Professor Mike Lean

Trial website

Contact information



Primary contact

Prof Mike Lean


Contact details

School of Medicine - GRI Campus
College of Medical
Veterinary and Life Sciences
University of Glasgow
2nd Floor
New Lister Building
Glasgow Royal Infirmary
10-16 Alexandra Parade
G31 2ER
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Bioavailabilty of Orange Juice polyphenols: a cross-over, non-randomised intervention



Study hypothesis

Including the detection and quantification of flavanone metabolites and their colonic microflora-mediated breakdown products in the investigation of orange juice polyphenol absorption and metabolism will lead to a better understanding of their real bioavailability in humans.

Ethics approval

University of Glasgow, MVLS College Ethics Committee, 21/12/2011, Project Number: 2011017

Study design

Cross-over non-randomised intervention

Primary study design


Secondary study design

Non randomised study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Bioavailabilty of orange juice polyphenols


Each subject will drink 250 ml of pulp-enriched orange juice. A light breakfast consisting of white bread, cheese, ham and milk will be provided 2 h after orange juice intake. After a wash-out period of 2 weeks, the volunteers will ingest 250 ml of a placebo drink. Following supplementation, all urine will be collected over five time periods (0, 0-2, 2-5, 5-10 and 10-24 hours).

Intervention type



Not Applicable

Drug names

Primary outcome measures

The absolute bioavailability of orange juice phenolics will be the primary outcome of this study. Polyphenol metabolites and catabolites will be identified and quantified in urine collected over five time periods (0, 0-2, 2-5, 5-10 and 10-24 hours) following supplementation, using high-performance liquid chromatography coupled with tandem mass spectrometry and gas chromatography coupled with mass spectrometry.

Secondary outcome measures


Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Healthy men and women.
2. Age 20-65 years

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Smoking
2. On no medication

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Glasgow Royal Infirmary
G31 2ER
United Kingdom

Sponsor information


The Coca-Cola Company (USA)

Sponsor details

c/o Dr Susan Roberts
GA 30313
United States of America

Sponsor type




Funder type


Funder name

The Coca-Cola Company (USA)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2014 results in:

Publication citations

Additional files

Editorial Notes