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Trial registered on ANZCTR


Registration number
ACTRN12619000789167
Ethics application status
Approved
Date submitted
17/05/2019
Date registered
28/05/2019
Date last updated
28/05/2019
Date data sharing statement initially provided
28/05/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Does a meal containing green tea extract lower diabetes risk?
Scientific title
Can a meal containing green tea extract lower postprandial glycaemia in healthy participants: a randomised crossover trial
Secondary ID [1] 298013 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Diabetes
312463 0
Post-prandial glycaemic response 312464 0
Condition category
Condition code
Metabolic and Endocrine 311014 311014 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study will investigate the effect of 6g of a green tea extract (high in polyphenols) cooked into a meal containing 50 g of available carbohydrates in the form of jasmine rice vs placebo (no green tea) in the morning and at night. The intervention will be run by University research students overseen by Senior University researchers.

Blood glucose will be measured at baseline, 15, 30, 45, 60, 90, 120, 150 and 180 minutes to assess the postprandial glucose response. Insulin will be measured at baseline and at 30, 60, 90, 120, 150 and 180 minutes post meal to assess postprandial insulin response. Participants will also complete questionnaires relating to their habitual diet and physical activity. This is a 4 way crossover with participants completing the test (polyphenol) and placebo meals in the morning and also in the evening.

Morning session

Participants will be provided with a standardised commercially available frozen meal to consume between 7 - 9 pm the night before each testing day, then will be asked to fast until testing is complete, drinking only water. Participants are also asked to avoid foods high in polyphenols and strenuous exercise for 24 hours prior to testing. Participants will be asked to come in to the lab at 7 am in the morning following an overnight fast. They will have an initial finger prick tests done to provide fasting levels of blood glucose and insulin then be given either a test meal or placebo meal containing 50 g of available carbohydrates from white rice, which must be consumed within 15 minutes.

Evening session
The same protocol as for the mornings will be carried out for evening testing, but with participants consuming a standardised commercially available frozen meal between 8 and 9 am and arriving at the testing facility at 6 pm after fasting throughout the day.

Participants will consume the test doses and placebo in a cross-over fashion (four sessions in total) with at least three days washout in between each treatment. All treatment will be administered and supervised on site.

Prior to each study session participants will be asked to confirm that they have fasted (either overnight or during the day depending on the session) and consumed the control meal provided.

Intervention code [1] 314246 0
Treatment: Other
Intervention code [2] 314247 0
Prevention
Comparator / control treatment
Cooked white rice (50 g of available carbohydrate) with no green tea extract
Control group
Active

Outcomes
Primary outcome [1] 319803 0
Postprandial blood glucose incremental area under the curve.
Samples will be capillary blood samples via finger prick and measured using the HemoCue system.
Timepoint [1] 319803 0
Blood samples taken at baseline and at 15, 30, 45, 60, 90, 120 and 180 minutes after test meal.
Primary outcome [2] 319804 0
Postprandial blood insulin incremental area under the curve.
Blood samples will be collected via fingerprick into 200 ul capillary tubes, centrifuges and frozen for batch analysis on completion of the trial. Insulin will be assessed using a radioimmunoassay.
Timepoint [2] 319804 0
Blood samples taken at baseline and at 30, 60, 90, 120, 150 and 180 minutes after test meal.
Secondary outcome [1] 369576 0
Postprandial blood glucose 'time to peak'.
Samples will be capillary blood samples via finger prick and measured using the HemoCue system.
Timepoint [1] 369576 0
Blood samples taken at baseline and at 15, 30, 45, 60, 90, 120 and 180 minutes after test meal.
Secondary outcome [2] 369578 0
Postprandial blood insulin 'time to peak'.
Blood samples will be collected via fingerprick into 200 ul capillary tubes, centrifuges and frozen for batch analysis on completion of the trial. Insulin will be assessed using a radioimmunoassay.
Timepoint [2] 369578 0
Blood samples taken at baseline and at 30, 60, 90, 120, 150 and 180 minutes after test meal. .

Eligibility
Key inclusion criteria
Body mass index (BMI) from 18.5 to less than 28 kg/m2, a fasting blood glucose test below 5.5 mmol/L
Minimum age
18 Years
Maximum age
65 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Taking medications that affect blood sugar
Taking natural health products that affect polyphenols (e.g. fish oil)
Implanted cardiac defibrillator
Pregnant, planning a pregnancy or breastfeeding
Gastrointestinal conditions that may affect polyphenol action
Serious health conditions that may affect participation e.g. liver or thyroid dysfunction, recent major surgery
Consume more than 4 alcoholic drinks per day
Current shift workers
Consume large amounts of herbal tea daily, e.g. green tea
Vegetarian and vegan

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The researcher conducting participant allocation will be separate from the researcher/s conducting participant screening. Allocation will remain hidden from the researcher doing the screening in a secure computer database.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using computerised sequence generation will be used to determine the order in which participants receive each treatment.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s

The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Twenty individuals will be recruited with the expectation that at least 16 will complete the whole protocol. Sample size calculations were performed, assuming 2-sided 0.80 power, with 0.05 significance level based on data from studies that have shown a change in postprandial blood glucose after consumption of a green tea extract (n = 10). in the morning (Chepulis et al, 2016). To detect a change of 40 units in postprandial blood glucose iAUC we require 14 people to complete the intervention. Equivalent data is not available for night.

All results will be assessed for normality. Paired t-tests will be used to compare the difference between intervention and placebo groups for blood glucose and insulin iAUC and blood glucose and insulin time to peak. Descriptive statistics (number and percentages) will be used to interpret intolerance symptoms.

Recruitment
Recruitment status
Not yet recruiting
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 in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 302537 0
University
Name [1] 302537 0
.Monash University
Address [1] 302537 0
.Dept of Nutrition, Dietetics and Food
Level 1, 264 Ferntree Gully Road
Notting Hill
Monash University
VIC, 3168
Country [1] 302537 0
Australia
Primary sponsor type
Individual
Name
A/Prof Maxine Bonham
Address
Department of Nutrition, Dietetics and Food,
Level 1, 264 Ferntree Gully Rd,
Notting Hill 3168, VIC
Country
Australia
Secondary sponsor category [1] 302448 0
None
Name [1] 302448 0
None
Address [1] 302448 0
None
Country [1] 302448 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303187 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 303187 0
Monash University
Room 111, Chancellery Building E
24 Sports Walk
Clayton Campus
Wellington Rd
Clayton VIC 3800
Ethics committee country [1] 303187 0
Australia
Date submitted for ethics approval [1] 303187 0
12/04/2019
Approval date [1] 303187 0
01/05/2019
Ethics approval number [1] 303187 0

Summary
Brief summary
Effect of eating at night time results in blood glucose levels up to 6 times higher than the same meal consumed in the morning. Dietary polyphenols favourably influence blood glucose, but studies are usually undertaken in the morning. We hypothesise that polyphenols from green tea incorporated into a meal may be effective at lowering blood glucose both in the morning and at night.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 92790 0
A/Prof Maxine Bonham
Address 92790 0
Monash University
Be Active Sleep Eat Facility
Level 1, 264 Ferntree Gully Road
Notting Hill VIC 3168
Country 92790 0
Australia
Phone 92790 0
+61 3 9902 4272
Fax 92790 0
Email 92790 0
maxine.bonham@monash.edu
Contact person for public queries
Name 92791 0
A/Prof Maxine Bonham
Address 92791 0
Monash University
Be Active Sleep Eat Facility
Level 1, 264 Ferntree Gully Road
Notting Hill VIC 3168
Country 92791 0
Australia
Phone 92791 0
+61 3 9902 4272
Fax 92791 0
Email 92791 0
maxine.bonham@monash.edu
Contact person for scientific queries
Name 92792 0
A/Prof Maxine Bonham
Address 92792 0
Monash University
Be Active Sleep Eat Facility
Level 1, 264 Ferntree Gully Road
Notting Hill VIC 3168
Country 92792 0
Australia
Phone 92792 0
+61 3 9902 4272
Fax 92792 0
Email 92792 0
maxine.bonham@monash.edu

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
No Results