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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

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]

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

Condition category

Condition code

Metabolic and Endocrine

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]

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]

Plasma glucose levels during the session. The plasma glucose level will be measured using glucose oxidase commercial kits (Stanbio).

Timepoint [1]

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]

Plasma insulin levels during the session. The plasma insulin levels will be measured using enzyme-linked immunosorbent assay (ELISA).

Timepoint [2]

Secondary outcome [1]

Plasma active GLP-1 levels during the session. The active GLP-1 levels will be measured using enzyme-linked immunosorbent assay (ELISA).

Timepoint [1]

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

Sex

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

1/06/2018

Actual

4/06/2018

Date of last participant enrolment

Anticipated

26/02/2019

Actual

19/02/2019

Date of last data collection

Anticipated

7/05/2019

Actual

19/04/2019

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

Hong Kong

State/province [1]

Funding & Sponsors

Funding source category [1]

University

Name [1]

The University of Hong Kong

Address [1]

1 Pokfulam Road, Pokfulam

Country [1]

Hong Kong

Primary sponsor type

University

Name

The University of Hong Kong

Address

1 Pokfulam Road, Pokfulam

Country

Hong Kong

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Human Research Ethics Committee - University of Hong Kong Research Services

Ethics committee address [1]

9/F, Knowles Building, University of Hong Kong, 1 Pokfulam Road, Pokfulam, Hong Kong Special Administrative Region.

Ethics committee country [1]

Hong Kong

Date submitted for ethics approval [1]

01/12/2017

Approval date [1]

28/12/2017

Ethics approval number [1]

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

Dr Jimmy Chun Yu Louie

Address

5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,

Country

Hong Kong

Phone

+852 2299 0677

Fax

[email protected]

Contact person for public queries

Name

Jimmy Chun Yu Louie

Address

5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,

Country

Hong Kong

Phone

+852 2299 0677

Fax

[email protected]

Contact person for scientific queries

Name

Jimmy Chun Yu Louie

Address

5S-14, Kadoorie Biological Sciences Building, The University of Hong Kong, 1 Pokfulam Road, Pokfulam,

Country

Hong Kong

Phone

+852 2299 0677

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

No/undecided IPD sharing reason/comment

To protect the privacy of participants

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Consumption of decaffeinated coffee with milk and sugar added before a high-glycemic-index meal lowers postprandial glucose surge when compared with consuming it after the meal.	2021	https://dx.doi.org/10.1016/j.hnm.2021.200124

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically