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Trial registered on ANZCTR


Registration number
ACTRN12619000958189
Ethics application status
Approved
Date submitted
28/06/2019
Date registered
8/07/2019
Date last updated
4/02/2020
Date data sharing statement initially provided
8/07/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of wholegrain structure on metabolism and breath volatile organic compounds
Scientific title
Effect of wholegrain structure on metabolism and composition of breath volatile organic compounds in adults with normal glucose tolerance or type 2 diabetes mellitus: a randomised crossover study
Secondary ID [1] 298580 0
Nil known
Universal Trial Number (UTN)
U1111-1235-8907
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 2 Diabetes 313420 0
Blood Glucose Control 313546 0
Condition category
Condition code
Metabolic and Endocrine 311855 311855 0 0
Diabetes
Metabolic and Endocrine 311981 311981 0 0
Normal metabolism and endocrine development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study is a randomised crossover design to measure the postprandial blood glucose and breath volatile organic compound (VOC) response to wholegrain breads of differing structure.

The trial includes three food exposures:
* A bread made from finely milled wholegrains (100% wholegrain flour) providing 50g available carbohydrate (approx. four slices) served with 250mL water
* A bread made from of mixture of finely ground and intact wholegrains providing 50g available carbohydrate (approx. four slices) served with 250mL water
* A 250ml glucose drink as a control (at a glucose concentration of 20g/100mL)

Both breads are matched for available carbohydrate and fibre content, and only differ in the particle size and structure of the wholegrains. All three foods will provide 50g of available carbohydrate. Intervention order will be randomised for the three foods. A washout period of 3 days will be adhered to between testing days.

Key measures:
1. Blood glucose levels are being measured from capillary blood obtained via finger prick.
2. Blood short chain fatty acids acetate, butyrate and propionate are being measured from venous blood collected from the arm.
3. Breath VOCs (Including short chain fatty acids) will be measured from breath using both Gas chromatography mass spectrometry (GC-MS) and Proton transfer reaction mass spectrometry (PTR-MS)

Participants will arrive at the research clinic between 8:00am and 9:30am after a minimum 10 hour water only fast. A text reminder will be sent 24 hours before to remind participants to follow their similar dietary and exercise pattern, and to fast from 10pm that evening. Before their first visit a food and exercise diary will be completed and used to remind participants. Participants will be asked to sit for at least 10 minutes, to stabilise heart rate and breathing rate levels. A questionnaire asking about any changes since the last visit and adherence to study requirements the day before will be completed. On the first visit a food frequency questionnaire will be completed to measure usual intake. Two capillary blood samples will be taken by finger prick for the measurement of baseline fasted blood glucose and one 6mL venous blood sample will be taken by a nurse. One single, full breath will be captured into a tedlar bag for GC-MS analysis, and three exhaled breaths into the PTR-MS before the test food will be provided.

Participants will have 10 minutes to consume the test foods alongside 250mL of water. The participant will provide three fully exhaled breaths into the PTR-MS and one capillary blood glucose will be taken at 30, 60, 90, 120, 180, 240, 270, 300, 330, 360 minutes following consumption. Breath samples will be provided using a clean, dedicated mouthpiece according to an established protocol*. At 180 minutes post consumption, another portion (same size as at baseline) of the test food will be provided with 250mL of water with 10 minutes allowed to consume. At 300 minutes post consumption, a second fully exhaled breath into a tedlar bag and 6mL venous blood sample will be collected. A total of 12mL of venous blood will be collected each test day.

Physical activity and meals in the 24 hours before each intervention will be standardised and participants asked to abstain from alcohol and strenuous exercise. Participants will be required to stay at the research clinic for approximately 6.5 hrs on each test day.

During the six hours of testing, participants will be encouraged to sit for the duration, moving only for the toilet, to wash their hands before each capillary finger prick and for breath measures. However, participants will be able to undertake their own activities such as reading, working on a computer, watching TV on their computer, or relaxing. At the end of each 6 h testing session, a small meal will be provided.

* Participants are seated in front of the breath testing buffer tube with feet flat and knees at 90 degrees, and back straight and vertical. They then inhale fully, hold for 2 seconds, before bringing their mouth to the breath buffer tube and fully exhaling steadily and with control.
Intervention code [1] 314839 0
Diagnosis / Prognosis
Intervention code [2] 314840 0
Early detection / Screening
Comparator / control treatment
This is a crossover design where each participant acts as their own control across interventions. The bread tests will be compared against each other, and against a glucose drink containing no indigestible carbohydrate.
Control group
Active

Outcomes
Primary outcome [1] 320526 0
Breath volatile organic compound (VOC) composition and concentration as assessed by PTR-MS and GC-MS analysis of tedlar bag.
Timepoint [1] 320526 0
Baseline and then 30, 60, 90, 120, 150. 180, 240, 270, 300, 330, and 360 minutes after first food provided.
Secondary outcome [1] 371925 0
Blood glucose concentration as assessed by finger-prick blood glucose monitor
Timepoint [1] 371925 0
Baseline and then 30, 60, 90, 120, 150. 180, 240, 270, 300, 330, and 360 minutes after first food provided.
Secondary outcome [2] 371926 0
Blood plasma short chain fatty acids as assessed by laboratory analysis of whole blood sample
Timepoint [2] 371926 0
At baseline and 300 minutes after first food provided.

Eligibility
Key inclusion criteria
Two groups of adults aged 18 to 79 years are sought; one group reporting they have previously been diagnosed with type 2 diabetes mellitus and one reporting that they have not previously been diagnosed with type 2 diabetes or impaired glucose tolerance (as self-reported at the time of the screening visit).
Minimum age
18 Years
Maximum age
79 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Exclusion criteria include pregnancy, lactation, infection, smoking in the past 12 months, taking any insulin or a sulfonylurea, changes to any medications known to affect blood glucose levels in the past month, any normal glucose tolerant (NGT) participant identified as having elevated blood glucose or HbA1c, use of antibiotics or weight change greater than 2kg in the past 3 months, or inability or unwillingness to consume gluten containing cereals or comply with the intervention requirements.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The randomised orders will be stored in sealed opaque envelopes.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A simple randomisation will be created with computer software. (Stata, Statacorp, 2017. Stata Statistical Software. College Station, TX: StataCorp LLC)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Assuming a within-person correlation of between 0.4 and 0.7, with a sample size of 12 we would have 80% power to detect a difference of between 0.7 and 1.0 standard deviations between treatments to the alpha=0.05 level. We intend to over recruit to better consider secondary outcomes; thus, we will recruit 16 participants with type 2 diabetes and 16 participants without type 2 diabetes or impaired glucose tolerance (IGT).

A Mixed effects regression model using food exposures and randomization order as fixed effects and participant as random effect will be done on the VOCs of interest. Comparisons to the control condition will be made as well as between the two wholegrain conditions.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
22/07/2019
Actual
16/08/2019
Date of last participant enrolment
Anticipated
Actual
29/11/2019
Date of last data collection
Anticipated
Actual
16/12/2019
Sample size
Target
32
Accrual to date
Final
27
Recruitment outside Australia
Country [1] 21643 0
New Zealand
State/province [1] 21643 0
Otago

Funding & Sponsors
Funding source category [1] 303120 0
Other
Name [1] 303120 0
Riddet Institute
Country [1] 303120 0
New Zealand
Primary sponsor type
University
Name
University of Otago
Address
Po Box 56
Dunedin 9010 Otago
Country
New Zealand
Secondary sponsor category [1] 303121 0
None
Name [1] 303121 0
None
Address [1] 303121 0
None
Country [1] 303121 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303671 0
Health and Disability Ethics Committee
Ethics committee address [1] 303671 0
Ethics committee country [1] 303671 0
New Zealand
Date submitted for ethics approval [1] 303671 0
27/06/2019
Approval date [1] 303671 0
25/07/2019
Ethics approval number [1] 303671 0
19/STH/129

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 94446 0
Mr Caleb Robinson
Address 94446 0
University of Otago
Department of Human Nutrition
PO Box 56
Dunedin Otago 9010
Country 94446 0
New Zealand
Phone 94446 0
+64273526748
Fax 94446 0
Email 94446 0
caleb.robinson@postgrad.otago.ac.nz
Contact person for public queries
Name 94447 0
Graham Eyres
Address 94447 0
University of Otago
Department of Food Science
PO Box 56
Dunedin Otago 9010
Country 94447 0
New Zealand
Phone 94447 0
+64 3 479 7661
Fax 94447 0
Email 94447 0
graham.eyres@otago.ac.nz
Contact person for scientific queries
Name 94448 0
Graham Eyres
Address 94448 0
University of Otago
Department of Food Science
PO Box 56
Dunedin Otago 9010
Country 94448 0
New Zealand
Phone 94448 0
+64 3 479 7661
Fax 94448 0
Email 94448 0
graham.eyres@otago.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
All data analyses will be completed by the research team for publication as this is exploring a novel method for examining carbohydrate metabolism.


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
No additional documents have been identified.