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Trial registered on ANZCTR


Registration number
ACTRN12618001576213
Ethics application status
Approved
Date submitted
26/07/2018
Date registered
21/09/2018
Date last updated
13/11/2020
Date data sharing statement initially provided
26/08/2019
Date results information initially provided
26/08/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of low vs high glycaemic index diet on day-long glycaemia in healthy adults
Scientific title
Effect of low vs high glycaemic index diet on day-long glycaemia in healthy adults
Secondary ID [1] 295652 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Postprandial blood glucose 309024 0
Condition category
Condition code
Metabolic and Endocrine 307913 307913 0 0
Normal metabolism and endocrine development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Two different study diets are provided i.e. low glycemic index (LGI) and high glycemic index (HGI). The subjects will be randomized to start the trial with one of the two study diets for 5 days. After that the subjects will have a 3-day wash-out period, and then they will be switched to the other diet for another 5 days. The details of the 2 study diets are as follows:

Study diets
We will use a meal-delivery service Eatology (http://www.eatologyasia.com) which allows customization of the foods to provide all foods during the study period. A sample 5-day menu is attached as appendix. We will discuss with their team to come up with meals and snacks that conforms to the following specifications, that are delicious and attractive:

Table 1 – Nutritional composition of the study diets
---------------------------------------------------------------------------------------------------------------
Parameter LGI diet HGI diet
Energy (kcal/d) 1600 (F) – 2000 (M) 1600 (F) – 2000 (M)
Protein (%kcal) 25 25
Carbohydrates (%kcal) 50 50
Total fats (& saturated fats) (%kcal) 25 (10) 25 (10)
Fibre (g/1000kcal) 15 15
Dietary GI 40-45 60-65
Dietary Glycemic Load (GL) 110-120 150-170
---------------------------------------------------------------------------------------------------------------
F- Female, M – Male. These are approximations only.
Two versions of each study diet will be formulated, one western-style and one Asian-style to cater for individual preference. The diets will be designed to be matched for macronutrient and fibre for each meal and the whole day, with a 15-25 units difference in dietary GI (i.e. the weighted average GI of all foods consumed by the carbohydrate contribution), and 40-50 units difference in dietary glycemic load (GL) (i.e. the sum of the GL from all foods). Only foods with a tested GI in the international GI database (Atkinson et al. Diabetes Care. 2010) will be used in the design of the study diets to ensure accuracy of the dietary GI which is calculated using the following formula:
Dietary GL * 100 / total available carbohydrates (in grams). The study foods will be delivered to the subjects’ home or office address daily, with instructions on how to store, reheat and prepare the foods properly.
After a 1-day run-in period, the subjects will be randomized to start the trial with one of the two study diets for 5 days. Then they will have a 3-day wash-out period before being switched to the other diet for another 5 days. The compositions of the diets are given in the next sub-section. All foods and drinks during the intervention periods (i.e. 2 × 5 days) will be provided, while the subjects are allowed to resume their normal diet during the run-in and wash-out period. Subjects will be instructed to eat only foods provided by the researchers through the meal-delivery service, and take and send photos before and after their meal for assessment of compliance. Subjects will be given a list of beverages they could consume which is appropriate for their assigned diet (for example, watermelon juice for HGI; most fruit juices other than watermelon juice for LGI. Water and sugar-free soft drinks are considered acceptable for both diets) . The subjects are required to take and send photos of all the drinks they taken.
In the evening of the run-in period, the research assistant will insert the FreeStyle CGMS sensor into the upper arm of the subject and calibrate the reader for use. Each FreeStyle CGMS sensor can last 14-days, will automatically sample blood glucose data every 15-minutes, and can store up to 8-hours’ worth of data since the last scan. Subjects will be educated on how to scan the sensor for data, and indicate their meal-time using the inbuilt function of the reader. They will be instructed to scan for data every 6-7 hours during the time they are awake to avoid loss of data.
Intervention code [1] 301989 0
Lifestyle
Comparator / control treatment
This study is a randomized cross-over short-term trial, where each subject acts as their own control.
Control group
Active

Outcomes
Primary outcome [1] 306894 0
Day-long glycaemia (as indicated by the AUC of glucose from the time the subject wakes up until he/she goes to sleep at night); Hyperglycaemic index, defined as the AUCglucose above 6.0 mmol/L divided by the total time of the observation period (i.e. 24 hours).
Timepoint [1] 306894 0
In the evening of day 1, the research assistant will insert the FreeStyle CGMS sensor into the upper arm of the subject and calibrate the reader for use. Each FreeStyle CGMS sensor will be stayed on each subject's arm for 14-days, The sensor will automatically sample blood glucose data every 15-minutes until the subjects finish the second study diet.
Secondary outcome [1] 350045 0
Mean amplitude of glycaemic excursion, which takes into account the glycaemic peaks and nadirs encountered during a day, beyond average glucose values, will be calculated using the standard formula (Diabetes Care. 2011 May; 34(Suppl 2): S120–S127)
Timepoint [1] 350045 0
In the evening of day 1, the research assistant will insert the FreeStyle CGMS sensor into the upper arm of the subject and calibrate the reader for use. Each FreeStyle CGMS sensor will be stayed on each subject's arm for 14-days, The sensor will automatically sample blood glucose data every 15-minutes until the subjects finish the second study diet.
Secondary outcome [2] 350085 0
Postprandial glycaemia (as indicated by the iAUC of glucose)
Timepoint [2] 350085 0
Breakfast, lunch, dinner and snack time as identified by the participants
Secondary outcome [3] 350086 0
A 5-point Likert scale will be given to the subjects to assess the subjects’ like or dislikes of the diet
Timepoint [3] 350086 0
At the end of each 5-day intervention period
Secondary outcome [4] 350087 0
Peak blood glucose at each meal derived from the record of FreeStyle CGMS sensors
Timepoint [4] 350087 0
Breakfast, lunch, dinner and snack time as identified by the participants

Eligibility
Key inclusion criteria
1. Aged between 18 – 40 years
2. Body mass index between 18.5 – 23 kg/m2
3. Non-smoking
4. Non-regular alcohol drinker
5. Generally healthy with no chronic disease (including type 2 diabetes)
6. No skin sensitivity issues
7. Able to wear the subcutaneous CGMS sensor for 14 days
8. Able to receive, store and reheat the study meals according to the instructions
9. No special dietary requirement including vegetarianism and veganism
10. Ownership of a smartphone with camera function
Minimum age
18 Years
Maximum age
40 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
1. Doctor’s diagnosis of any form of impaired glucose tolerance
2. Doctor’s diagnosis of any chronic diseases
3. Individuals with impaired immunity
4. Regularly taking any form of medication (except oral contraceptives)
5. Women who are pregnant or planning to be pregnant during the study

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
26/09/2018
Actual
26/09/2018
Date of last participant enrolment
Anticipated
Actual
19/12/2018
Date of last data collection
Anticipated
Actual
27/02/2019
Sample size
Target
15
Accrual to date
Final
15
Recruitment outside Australia
Country [1] 10686 0
Hong Kong
State/province [1] 10686 0

Funding & Sponsors
Funding source category [1] 300232 0
University
Name [1] 300232 0
The University of Hong Kong
Country [1] 300232 0
Hong Kong
Primary sponsor type
University
Name
The University of Hong Kong
Address
University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong
Country
Hong Kong
Secondary sponsor category [1] 299647 0
None
Name [1] 299647 0
Address [1] 299647 0
Country [1] 299647 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 301055 0
Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (HKU/HA HKW IRB)
Ethics committee address [1] 301055 0
Rm 901, 9/F, Administration Block, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong
Ethics committee country [1] 301055 0
Hong Kong
Date submitted for ethics approval [1] 301055 0
08/05/2018
Approval date [1] 301055 0
05/06/2018
Ethics approval number [1] 301055 0
UW 18-313

Summary
Brief summary
Chronic postprandial hyperglycaemia, even within the normal physiological range, may lead to adverse health outcomes in the long term. Postprandial hyperglycaemia has been shown to increase oxidative stress, and may cause glycation of protein and enzymes important for glucose metabolism. Thus finding a diet which may limit postprandial glucose excursions and overall daylong glycaemia is important for the promotion of health. Furthermore, if such a diet is found among healthy subjects, there is real impedes to further test such diet among patients with T2DM, who face daily challenges to keep their blood glucose levels within clinically acceptable ranges. Previous studies examining the effect of LGI diets on glycaemic control rarely collect data on daily long glycaemic profile of the subjects, and hence the utility of a LGI diet in the management of hyperglycaemia was not universally accepted, even though theoretically it should improve glycaemic control. Utilizing the latest technology in continuous blood glucose monitoring systems (CGMS), this proof-of-concept study will provide pilot data to support a proposal for a clinical trial amongst subjects with T2DM, which may generate the much needed evidence to support the use of a LGI diet as a first line management for T2DM.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 85730 0
Dr Jimmy Chun Yu Louie
Address 85730 0
School of Biological Sciences, Kadoorie Biological Sciences Building, University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong
Country 85730 0
Hong Kong
Phone 85730 0
+852 2299 0677
Fax 85730 0
+852 2559 9114
Email 85730 0
jimmyl@hku.hk
Contact person for public queries
Name 85731 0
Dr Jimmy Chun Yu Louie
Address 85731 0
School of Biological Sciences, Kadoorie Biological Sciences Building, University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong
Country 85731 0
Hong Kong
Phone 85731 0
+852 2299 0677
Fax 85731 0
+852 2559 9114
Email 85731 0
jimmyl@hku.hk
Contact person for scientific queries
Name 85732 0
Dr Jimmy Chun Yu Louie
Address 85732 0
School of Biological Sciences, Kadoorie Biological Sciences Building, University of Hong Kong, Pokfulam Road, Pokfulam, Hong Kong
Country 85732 0
Hong Kong
Phone 85732 0
+852 2299 0677
Fax 85732 0
+852 2559 9114
Email 85732 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 the participants


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
TypeIs Peer Reviewed?DOICitations or Other DetailsAttachment
Plain language summaryNo In young healthy adults, following a low glycaemic... [More Details]

Documents added automatically
No additional documents have been identified.