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Trial registered on ANZCTR


Registration number
ACTRN12621000012875p
Ethics application status
Submitted, not yet approved
Date submitted
3/11/2020
Date registered
11/01/2021
Date last updated
14/10/2021
Date data sharing statement initially provided
11/01/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
A study on the effect of kiwifruit on exercise performance.
Scientific title
Evaluating the effect of partial kiwifruit exchange of high glycaemic index (GI) carbohydrate on exercise performance in healthy individuals
A randomised, repeated measures, human intervention study
Secondary ID [1] 302682 0
None
Universal Trial Number (UTN)
U1111-1260-6404
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Exercise performance 319932 0
Condition category
Condition code
Metabolic and Endocrine 317537 317537 0 0
Normal metabolism and endocrine development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Each participant will receive each intervention listed below on a trial day, to consume within 10 minutes, in a randomised order separated by at least one week. Participants will
1. Weet-Bix™: containing 40 g available carbohydrate moistened with 180 ml water
2. Kiwifruit 30 minutes prior to Weet-Bix™: Weet-Bix™ (20 g available carbohydrate) and kiwifruit (20 g available carbohydrate)
3. Weet-Bix™ 30 minutes prior to another portion of Weet-Bix™: Weet-Bix™ (20 g x 2 available carbohydrate) moistened with 180 ml water.

135 minutes after the dietary intervention, exercise performance (power output, time and distance) will be assessed with a 30 minute cycle.
Intervention code [1] 318963 0
Prevention
Comparator / control treatment
The study aims to evaluate the effect of partial carbohydrate exchange of kiwifruit fed 30 minutes before Weet-Bix on blood glucose response and exercise performance. The control will be Weet-bix fed alone. Each participant will receive all diets and will act as their own control.
Control group
Active

Outcomes
Primary outcome [1] 325578 0
Cardiopulmonary parameters: O2/CO2 exchange, VO2 max, respiratory exchange ratio (RER), ventilation will be measured with a face mask and measured with a Cortex Metalyzer 3B Cardiopulmonary exercise testing (CPET) machine.
Timepoint [1] 325578 0
Measures will be taken continuously during a 30 minute cycle applied at 135 minutes after the last test meal on each trial day.
Primary outcome [2] 325887 0
Exercise performance: Power output, exercise duration (time and distance)
Timepoint [2] 325887 0
Measures will be taken continuously during a 30 minute cycle applied at 135 minutes after the last test meal on each trial day.
Primary outcome [3] 325888 0
Heart rate will be measured with a heart rate monitor.
Timepoint [3] 325888 0
Heart rate will be taken continuously during a 30 minute cycle applied at 135 minutes after the last test meal on each trial day.
Secondary outcome [1] 388439 0
Biochemical outcomes:
Whole blood glucose will be measured via a finger prick capillary blood draw.
Plasma insulin, glucagon and IL-6 will be measured via a finger prick capillary blood draw.
Plasma malodialdehyde (a measure of oxidative stress), lactate and use the Oxidative Potential assay (OPA) and the Ferric Reducing Antioxidant Power (FRAP) assays as a measures of antioxidant potential.
Timepoint [1] 388439 0
Blood glucose will be taken -30 mins (baseline 1) prior to diet intervention, 0 min (baseline 2) 15 min, 30 min, 45 min, 60 min, 90 min, 120 min, 165 min (post-exercise) on each trial day.
Insulin, glucagon and IL-6 will be taken -30 mins (baseline 1) prior to diet intervention, 0 min (baseline 2), 30 min, 45 min, 60 min, 90 min, 120 min, 165 min (post-exercise) on each trial day.
Lactate, malodialdehyde, OPA and FRAP will be taken -30 mins (baseline 1) prior to diet intervention, 120 min, 165 min (post-exercise) on each trial day.
Secondary outcome [2] 388440 0
Mood state outcomes:
Subjective scores: Perceived mood state questionnaire (POMS-SF).
Timepoint [2] 388440 0
These questionnaires will be taken at -30 mins (baseline 1) prior to the dietary intervention, 120 min, 165 min (post-exercise) on trial days.
Secondary outcome [3] 388441 0
Exercise performance outcomes:
Subjective scores: Rating of Perceived Exertion (RPE)
This is a scale from 1-10 on how much effort the participant believes they are applying to the 30 minute exercise intervention.
Timepoint [3] 388441 0
The rating will be take every 5 minutes during the 30 minute cycling session applied at 135 min after the last dietary intervention meal.
Secondary outcome [4] 389432 0
Satiety outcomes:
Subjective scores: Visual analogue scale questionnaire.
Timepoint [4] 389432 0
These questionnaires will be taken at -30 mins (baseline 1) prior to the dietary intervention, 120 min, 165 min (post-exercise) on trial days.

Eligibility
Key inclusion criteria
• Age: Aged between 18 and 55.
• Sex: Male or female.
• Glucose tolerance: No history of diabetes or evidence of glucose intolerance in a preliminary screening test.
• HBA1c <40 mmol/mol
• BMI: Volunteers have a body mass index between 18.5 and 30 kg/m2
• Health: Healthy as gauged by self-assessment and result on the General Health Questionnaire.
• Agreement: Participant having given written informed consent to comply with the conditions of the trial.
Minimum age
18 Years
Maximum age
55 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Glucose intolerance: Any history of diabetes or evidence of glucose intolerance in a preliminary test (Greater than or equal to 6.0mmol/l fasting glucose, International Diabetes Federation recommendation) and HbA1c greater than 40 mmol/mol.
Non-fasting: Having consumed anything apart from water in the twelve hours prior to the test.
Allergic or intolerant kiwifruit or wheat
Pregnant or breastfeeding or planning to get pregnant in the near future.
Long term chronic illnesses requiring treatment, such as cancer and cardiovascular disease.
Gut conditions or drugs effecting gut transit time, such as irritable bowel syndrome, peptic ulcers and laxatives.
Habitual Physical Activity questionnaire sports index greater than 4, assessed by a Baecke questionnaire.
Participants will be excluded if they are unwilling or unable to provide informed consent or comply with the study procedures.
Participants that have health conditions that impair their ability to perform the exercises or may be aggravated by the exercises in this study (e.g. injury, hernia, back or joint pain, cardiovascular and breathing problems).
Participants that have Type I or II diabetes or are pre-diabetic (ii) blood borne diseases (e.g. hepatitis), (iii) clinically diagnosed high/low blood pressure, (iv) recent bacterial or viral illness or (v) are taking medication that affects the properties of blood (e.g. blood clotting).

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)
Allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation).
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Due to the nature of the diets containing kiwifruit and Weet-bix we are unable to mask the diet from the participant.
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
The participant number specified by the current ISO method (ISO 26642:2010) for determination of glycaemic index is n=10, and is typical of studies involving comparisons of foods. Our previous exercise trial used 15 participants which was based on a power calculation using oxidative stress measures as the primary outcome. We will recruit 20 participants to account for potential drop outs during the trial. This is a preliminary study and our first to use exercise performance as a primary measure and therefore this study will be used to power future studies based on exercise performance.
Data will be expressed as mean values and standard errors of the mean. Statistical significance for comparison between time points and treatment groups will be assessed using paired Student’s t-test. Where multiple comparisons are required, a two-way ANOVA mixed design will be applied. Where appropriate, the original data will be transformed to achieve normality and constant variance in the residuals. Statistical significance for all indices will be set a P < 0.05 with a confidence level of 95%.
All statistical analyses will be completed by a statistician at Plant & Food Research.
Statistical analysis will describe the differences between the foods in their effects on cardiopulmonary parameters (O2/CO2 exchange, VO2 max, respiratory exchange ratio (RER), ventilation and heart rate), exercise performance (power output, exercise duration (time and distance), along with other biomarkers and questionnaire scores at different postprandial time points.

Recruitment
Recruitment status
Withdrawn
Reason for early stopping/withdrawal
Lack of funding/staff/facilities
Date of first participant enrolment
Anticipated
1/02/2021
Actual
Date of last participant enrolment
Anticipated
5/04/2021
Actual
Date of last data collection
Anticipated
31/12/2021
Actual
Sample size
Target
20
Accrual to date
Final
Recruitment outside Australia
Country [1] 23084 0
New Zealand
State/province [1] 23084 0
Manawatu

Funding & Sponsors
Funding source category [1] 307121 0
Other
Name [1] 307121 0
The New Zealand Institute for Plant & Food Research
Country [1] 307121 0
New Zealand
Primary sponsor type
Other
Name
The New Zealand Institute for Plant & Food Research
Address
Private Bag 11600
Palmerston North 4442
Country
New Zealand
Secondary sponsor category [1] 307696 0
None
Name [1] 307696 0
None
Address [1] 307696 0
None
Country [1] 307696 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 307233 0
Health and Disability Ethics Committee
Ethics committee address [1] 307233 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 307233 0
New Zealand
Date submitted for ethics approval [1] 307233 0
07/12/2020
Approval date [1] 307233 0
Ethics approval number [1] 307233 0

Summary
Brief summary
The key research question is whether the reduction in hypoglycaemic response following a kiwifruit pre-load prior to a Weet-bix™ meal improves exercise performance. Our previous research has shown that ingestion of kiwifruit 30 minutes prior to Weet-Bix™ substantially reduces glycaemic response peak height when compared to Weet-Bix™ fed alone or WeetBix consumed at the same time as kiwifruit and reduces the hypoglycaemic state that commonly occurs after eating available carbohydrates. We hypothesise that the increase in available glucose in the circulation will fuel muscles and therefore improve the exercise performance.
Standard glycaemic response testing protocols will be used, with an exercise intervention of 30 minutes cycling at 135 minutes after the last test meal. The available carbohydrate of all foods will be determined in-house before the trial to ensure all test diets contain 40 g of available carbohydrate.
The test foods will be as follows:
1. Weet-Bix™: containing moistened with 180 ml water
2. Kiwifruit 30 minutes prior to Weet-Bix™
3. Weet-Bix™ 30 minutes prior to another portion of Weet-Bix™: Weet-Bix™
A randomised cross-over design will be used in which all participants receive each diet once, with a minimum of a week separating each trial day. Blood glucose response will be measured at nine time points over a 195 minute period via finger prick. Additional capillary blood samples will be taken at eight time points over this period for measurement of insulins, glucagon and interleukin 6 and three venous blood samples will be taken at baseline, 120 mins (pre-exercise) and 165 mins (post-exercise) after the second test meal for measurements of oxidative stress. Exercise performance will be measured by cardiopulmonary parameters, power output, exercise duration and ratings of perceived exertion. We will also collect measures of hunger via a visual analogue questionnaire and mood with a perceived mood state questionnaire at baseline, 120 mins and 165 mins.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 106498 0
Dr John Monro
Address 106498 0
The New Zealand Institute for Plant & Food Research
Private Bag 11600
Palmerston North 4442
Country 106498 0
New Zealand
Phone 106498 0
+64 6 35556137
Fax 106498 0
Email 106498 0
[email protected]
Contact person for public queries
Name 106499 0
John Monro
Address 106499 0
The New Zealand Institute for Plant & Food Research
Private Bag 11600
Palmerston North 4442
Country 106499 0
New Zealand
Phone 106499 0
+64 6 35556137
Fax 106499 0
Email 106499 0
[email protected]
Contact person for scientific queries
Name 106500 0
John Monro
Address 106500 0
The New Zealand Institute for Plant & Food Research
Private Bag 11600
Palmerston North 4442
Country 106500 0
New Zealand
Phone 106500 0
+64 6 35556137
Fax 106500 0
Email 106500 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
We will be publishing means and standard errors of participants results only.


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.