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Trial registered on ANZCTR


Registration number
ACTRN12618000645257
Ethics application status
Approved
Date submitted
3/04/2018
Date registered
23/04/2018
Date last updated
13/06/2019
Date data sharing statement initially provided
9/11/2018
Date results information initially provided
13/06/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of drinking coffee at different time-points around a meal on after-meal blood glucose metabolism
Scientific title
The effect of drinking coffee at different time-points around a high glycemic index meal on postprandial blood glucose metabolism
Secondary ID [1] 294491 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postprandial blood glucose and insulin levels 307259 0
Condition category
Condition code
Metabolic and Endocrine 306378 306378 0 0
Normal metabolism and endocrine development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The time-points of interest in this study are 60, 30 and 15 minutes before meal (the pre-feeding sessions), and 10 minutes after meal (the post-feeding sessions). There will be two sessions for each time-point, thus making up a total of eight sessions for each participant. The sessions will be carried out in a random order, with at least 3 days apart..

In pre-feeding sessions, participants will first consume the test drinks. Each cup of test drink is made by mixing 2g decaffeinated coffee granules, 50g low-fat cow’s milk, and 7.5g white sugar with 140ml hot water. Participants are required to finish the test drink in 5 minutes.

Depending on the time-point allocated to that session, after 15, 30 or 60 minutes, they will consume a standard breakfast, which consists of 30g Kellogg’s Rice Krispies and 150g rice milk. They are required to finish the standard breakfast in 10 minutes.

In post-feeding sessions, upon the participants' arrival, they will first consume the same standard breakfast. They are required to finish the breakfast in 10 minutes and after that, they are required to drink the test drink in 5 minutes.

All test drinks and standard breakfasts will be prepared by a research staff. He also makes sure that the participants finish the breakfast and test drinks within the time limit.
Intervention code [1] 300787 0
Lifestyle
Comparator / control treatment
The control arm is 60 minutes before meal. Participants will first consume the test drinks, which consists of decaffeinated coffee with low-fat cow’s milk and white sugar added. They are required to finish the test drink in 5 minutes. After 60 minutes, they will consume a standard breakfast, which consists of 30g Kellogg’s Rice Krispies and 150g rice milk. They are required to finish the standard breakfast in 10 minutes.

All test drinks and standard breakfasts will be prepared by a research staff. He also makes sure that the participants finish the breakfast and test drinks within the time limit.
Control group
Active

Outcomes
Primary outcome [1] 305388 0
Plasma glucose levels during the session. The plasma glucose level will be measured using glucose oxidase commercial kits (Stanbio).
Timepoint [1] 305388 0
In pre-feeding sessions, a blood sample will be collected upon the participants' arrival. Then the time of the next blood sample collection depends on the time-point allocated to that particular session (15, 30, or 60 minutes after test drink consumption). Further blood samples will also be collected at specific time-points after meal i.e. 15, 30. 45, 60, 90, and 120 minutes (primary endpoint) after meal.

In post-feeding sessions, a blood sample will be collected upon the participants' arrival. Then further blood samples will be collected at specific time-points after meal (15, 30, 45, 60, 90, 120, and 180 minutes).

In all sessions, 8 blood samples will be collected in total.
Primary outcome [2] 305389 0
Plasma insulin levels during the session. The plasma insulin levels will be measured using enzyme-linked immunosorbent assay (ELISA).
Timepoint [2] 305389 0
In pre-feeding sessions, a blood sample will be collected upon the participants' arrival. Then the time of the next blood sample collection depends on the time-point allocated to that particular session (15, 30, or 60 minutes after test drink consumption). Further blood samples will also be collected at specific time-points after meal i.e. 15, 30. 45, 60, 90, and 120 minutes (primary endpoint) after meal.

In post-feeding sessions, a blood sample will be collected upon the participants' arrival. Then further blood samples will be collected at specific time-points after meal (15, 30, 45, 60, 90, 120, and 180 minutes).

In all sessions, 8 blood samples will be collected in total.
Secondary outcome [1] 345038 0
Plasma active GLP-1 levels during the session. The active GLP-1 levels will be measured using enzyme-linked immunosorbent assay (ELISA).
Timepoint [1] 345038 0
In pre-feeding sessions, a blood sample will be collected upon the participants' arrival. Then the time of the next blood sample collection depends on the time-point allocated to that particular session (15, 30, or 60 minutes after test drink consumption). Further blood samples will also be collected at specific time-points after meal (15, 30. 45, 60, 90, and 120 minutes).

In post-feeding sessions, a blood sample will be collected upon the participants' arrival. Then further blood samples will be collected at specific time-points after meal (15, 30, 45, 60, 90, 120, and 180 minutes).

In all sessions, 8 blood samples will be collected in total.

Eligibility
Key inclusion criteria
The criteria of taking part in this study are as follow:
- Aged between 18-40 years old
- Body mass index (BMI) WITHIN the range of 18.0-23.0
- Consumed at least 1 cup of coffee per day in the past 3 months
- Have never smoked before
- Able to tolerate cow’s milk
- Able to tolerate pork (present in the standard dinner)
- Able to tolerate coffee
- Not on regular medication, except oral contraceptives
- Women who are not pregnant or does not plan to be pregnant during the study
- Without high blood lipid or cholesterol
- Without current or history of type 1 or type 2 diabetes
- Without current or history of cardiovascular diseases
- Without current or history of liver diseases
- Without current or history of gastrointestinal diseases
- Without hemophobia
Minimum age
18 Years
Maximum age
40 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
- hemophobia
- cannot tolerate coffee
- cannot tolerate cow's milk
- current and ex-smoker
- do not consume coffee habitually

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 10254 0
Hong Kong
State/province [1] 10254 0

Funding & Sponsors
Funding source category [1] 299115 0
University
Name [1] 299115 0
The University of Hong Kong
Address [1] 299115 0
1 Pokfulam Road, Pokfulam
Country [1] 299115 0
Hong Kong
Primary sponsor type
University
Name
The University of Hong Kong
Address
1 Pokfulam Road, Pokfulam
Country
Hong Kong
Secondary sponsor category [1] 298373 0
None
Name [1] 298373 0
Address [1] 298373 0
Country [1] 298373 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 300048 0
Human Research Ethics Committee - University of Hong Kong Research Services
Ethics committee address [1] 300048 0
9/F, Knowles Building, University of Hong Kong, 1 Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region.
Ethics committee country [1] 300048 0
Hong Kong
Date submitted for ethics approval [1] 300048 0
01/12/2017
Approval date [1] 300048 0
28/12/2017
Ethics approval number [1] 300048 0
EA1712012

Summary
Brief summary
Coffee is a staple drink worldwide and is mainly consumed for its stimulating effect. The protective effects of habitual coffee consumption towards several chronic diseases related to unhealthy lifestyles, such as type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVD) and metabolic syndrome, have been demonstrated. However, these findings contradict with the results of acute feeding studies, which found that coffee is capable of impairing the body's own ability to control blood sugar level. This project aims at investigating the acute effect of consuming coffee at different time-points before or after meals on postprandial blood glucose and lipid levels.

The outcome of this project enables the identification of the optimal time of drinking coffee around meal time, in terms of leading to the most beneficial changes in the biomarkers measured. This may explain the discrepancies between the results of acute feeding trials and epidemiological studies. Further investigation of the biological mechanisms involved may also be developed depending on the results of this project.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 82386 0
Dr Jimmy Chun Yu Louie
Address 82386 0
5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,
Country 82386 0
Hong Kong
Phone 82386 0
+852 2299 0677
Fax 82386 0
Email 82386 0
jimmyl@hku.hk
Contact person for public queries
Name 82387 0
Dr Jimmy Chun Yu Louie
Address 82387 0
5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,
Country 82387 0
Hong Kong
Phone 82387 0
+852 2299 0677
Fax 82387 0
Email 82387 0
jimmyl@hku.hk
Contact person for scientific queries
Name 82388 0
Dr Jimmy Chun Yu Louie
Address 82388 0
5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,
Country 82388 0
Hong Kong
Phone 82388 0
+852 2299 0677
Fax 82388 0
Email 82388 0
jimmyl@hku.hk

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
To protect the privacy of participants
What supporting documents are/will be available?
Ethical approval
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary