Plain English Summary
Background and study aims
Antioxidants are substances that may prevent or delay some types of cell damage (oxidative stress). The human diet provides a wide range of plant-derived phenolics with antioxidant effects. The body’s response to antioxidant-rich foods is determined by the bioavailability of the active molecules - the proportion which enters the circulation and so is able to have an active effect. However, phenolics are generally consumed in foods along with other nutrients such as proteins, fats and sugars. These nutrients may have an impact on the phenolics’ bioavailability. In many countries, polyphenol-rich food like tea or fruit juice is usually consumed with milk. Although there still some discrepancies, many researchers have reported milk reduces the phenolics’ bioavailability. However, the effect of the different components in milk on phenolics’ bioavailability is not known. The aim of this study is to examine the role of different milk components (protein, lipid, lactose) on the phenolics’ bioavailability.
Who can participate?
Healthy volunteers aged 18 - 65
What does the study involve?
Participants are asked to consume their regular diet while avoiding foods rich in polyphenols for 2 days before each study day. These foods include fruit, vegetables, high fibre products, and drinks such as tea, coffee, fruit juice and wine. On five different study days (with a 1-week break between them), participants are randomly allocated to one of five treatments: (a) jujube fruits and water; (b) jujube fruits and whole milk; (c) jujube fruits and skimmed milk; (d) jujube fruits and cream; (e) whole milk and water. Blood samples are collected from all participants 1, 2, 3, 4, 6, 8 hours later. Urine is collected 24 hours before each study day and over five time periods (0–2, 2–5, 5–8, 8-12 and 12–24 hours) after the drinks.
What are the possible benefits and risks of participating?
The results will show whether milk components affect the bioavailability of phenolics. There are no known risks to participants.
Where is the study run from?
China Agricultural University (China)
When is the study starting and how long is it expected to run for?
September 2011 to October 2011
Who is funding the study?
National Science and Technology Support Program (China)
Who is the main contact?
Prof. Fazheng Ren
renfazheng@263.net
Trial website
Contact information
Type
Scientific
Primary contact
Prof Fazheng Ren
ORCID ID
Contact details
17 Tsing Hua East Road
HaiDian District
Beijing
100083
China
-
renfazheng@263.net
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
Effect of different components in milk on bioavailability of phenolic acid in humans: a randomised crossover interventional study
Acronym
Study hypothesis
The presence of fat in milk will offer more locations for protein linking with phenolics. It means that the effect of cream on phenolics bioavailability is through the presence of mik protein. Accordingly, the phenolics increase fat globule size during digestion will affect the lipid absorption. Furthermore, the effect of lactose and ion in milk on phenolics bioavailability in vivo is not yet evaluated.
Ethics approval
Not provided at time of registration
Study design
Randomised crossover feeding intervention study
Primary study design
Interventional
Secondary study design
Randomised cross over trial
Trial setting
Hospitals
Trial type
Other
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Condition
Nutrition
Intervention
The acute effects were assessed and compared on five different days (with a 1-week interval between them), using a Latin-square design. The participants were asked to consume their regular diet while avoiding foods rich in polyphenols for 2 days before each study day. These foods included fruit, vegetables, high fibre products, beverages such as tea, coffee, fruit juice and wine. On each study day, the participants arrived at 9am after an overnight fast. Baseline blood was sampled and then participants were randomly assigned to one of five treatments.
Treatments included:
1. 200g jujube fruits and 200ml water
2. 200g jujube fruits and 200ml whole milk
3. 200g jujube fruits and 200ml skimmed milk
4. 200g jujube fruits and 200ml cream
5. 200ml whole milk and 200ml water
Intervention type
Other
Phase
Not Applicable
Drug names
Primary outcome measures
Phenolic acids in plasma and urine measured at 1, 2, 3, 4, 6, 8 hours after intervention
Secondary outcome measures
1. Serum triacylglycerols, total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol
2. Total antioxidant capacity in plasma
3. Resistance of serum lipids to oxidation
The outcomes will be measured at 1, 2, 3, 4, 6, 8 hours after intervention
Overall trial start date
17/09/2011
Overall trial end date
29/10/2011
Reason abandoned
Eligibility
Participant inclusion criteria
1. Healthy males or females
2. Aged 18 - 65
Participant type
Healthy volunteer
Age group
Adult
Gender
Both
Target number of participants
20
Participant exclusion criteria
1. Severe obesity, Body Mass Index (BMI) > 32 kg/m2
2. Metabolic and endocrine diseases
3. Malabsorption syndromes
4. Current smoking or smoking cessation for < 6 months
5. Alcohol abuse (> 40 g alcohol/d)
6. Pregnancy/lactation
7. Food allergy
8. Milk intolerance
9. Vegetarian
10. Blood donation or blood transfusion less than 3 months prior to the study
11. Major surgery within the 3 months preceding the study
12. Simultaneous participation in another drug trial and use of dietary supplements or any form of medication
Recruitment start date
17/09/2011
Recruitment end date
29/10/2011
Locations
Countries of recruitment
China
Trial participating centre
17 Tsing Hua East Road
Beijing
100083
China
Sponsor information
Organisation
China Agricultural University (China)
Sponsor details
College of Food Science and Nutritional Engineering
17 Tsing Hua East Road
HaiDian
Beijing
100083
China
Sponsor type
University/education
Website
Funders
Funder type
Government
Funder name
National Science and Technology Support Program (China) ref: 2011BAD09B03
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
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