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Trial registered on ANZCTR


Registration number
ACTRN12621000481875p
Ethics application status
Submitted, not yet approved
Date submitted
10/02/2021
Date registered
23/04/2021
Date last updated
23/04/2021
Date data sharing statement initially provided
23/04/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of a 12-week low carbohydrate vs a high carbohydrate weight loss diet on oxidative stress and inflammation in New Zealand defence force personnel.
Scientific title
The effect of a 12-week low carbohydrate vs a high carbohydrate weight loss diet on oxidative stress and inflammation in New Zealand defence force personnel.
Secondary ID [1] 301516 0
Nil
Universal Trial Number (UTN)
U1111-1253-5499
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Overweight 317865 0
Obesity 317866 0
Condition category
Condition code
Diet and Nutrition 315910 315910 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This randomised controlled trial (RCT) is a 12-week dietary intervention comparing a low carbohydrate, high fat (LCHF) way of eating with a control mainstream-nutrition-guided group in a group of navy personnel from the New Zealand Defence Force (NZDF). The LCHF diet is defined as <130g carbohydrates per day; 15-25% of total energy from protein; >60% of total energy from fat. Participants will be required to consume 3 meals a day (or the addition of more meals as long as it does not exceed their energy threshold) for 12 weeks. Participants will be expected to prepare their own food but will be provided with detailed instructions / resources / recipes to assist them. Resources provided to them will be a combination of those designed specifically for this research, and associated websites for recipes and other information (www.ditchthecarbs.com and www.dietdoctor.com). The dietitian and nutritionist will be administering the intervention. Participants will be required to track their dietary intake for a 2-week period at two time-frames (weeks 1-3, and weeks 6-8) on a free smart phone app called Easy Diet Diary. This will be sent to the research team who has access to the partner application, Foodworks for analysis. Research assistants that are nutrition-trained will be undertaking group sessions with participants every two weeks, where they will use food frequency questionnaires to measure adherence.
Intervention code [1] 317824 0
Lifestyle
Comparator / control treatment
The control group will be getting a dietary intervention based on Ministry of Health guidelines (45-65% carbohydrate; 15-25% protein and 20-35% fat).
Control group
Active

Outcomes
Primary outcome [1] 324122 0
F2 isoprostane, a marker of oxidative stress, will be measured from the urine and analysed using the ELISA technique.
Timepoint [1] 324122 0
F2 isoprostane will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over.
Primary outcome [2] 324123 0
Blood will be analysed for the fatty acid ratio of arachidonic acid AA) to eicosapentanoic acid (EPA) and analysis conducted on the changes in fatty acid content over the 12 week period.
Timepoint [2] 324123 0
Fatty acid ratios will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over.
Primary outcome [3] 326502 0
Blood will be analysed for the omega 6 fatty acid: total omega 3 fatty acid ratio
Timepoint [3] 326502 0
Total omega 6 and 3 ratio will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over.
Secondary outcome [1] 383817 0
Weight will be measured on a set of digital scales.
Timepoint [1] 383817 0
Weight will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over, as well as every two weeks of the intervention.
Secondary outcome [2] 383818 0
Body fat will be measured using a Bioelectric Impedance Spectroscopy device.
Timepoint [2] 383818 0
Body fat will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over,
Secondary outcome [3] 390860 0
Visceral fat will be measured using a Bioelectric Impedance Spectroscopy device.
Timepoint [3] 390860 0
Visceral fat will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over,
Secondary outcome [4] 393384 0
Waist circumference will be measured using a lufin tape measure.
Timepoint [4] 393384 0
Waist circumference will be measured in all participants at baseline (in the week of data collection prior to the start of the intervention) and during the data collection week after the 12-week intervention is over,
Secondary outcome [5] 393385 0
Blood sugar will be measured using a continuous blood sugar monitoring device (Freestyle Libre) in a sub-sample of participants in both groups.
Timepoint [5] 393385 0
Continuous blood sugar monitoring will be conducted for 2 weeks (week 6-8) of the 12 week intervention.

Eligibility
Key inclusion criteria
Navy personnel that are over 125kg and are registered on the FIT for LIFE programme with the NZ Defence Force
Minimum age
18 Years
Maximum age
70 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Less than 125 kg
Not on the FIT FOR LIFE programme
Pregnant or breastfeeding females

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



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Sample size analysis: Using the PASS 13 software and an ANCOVA model, we estimated that 38 subjects will allow us to detect a between-group post-intervention difference in 8-Isoprostane F2a of 0.12 (ng/mg creatinine) with 90% power (conservatively assuming a within-group standard deviation of 0.4, and a covariate [baseline measurement] R2 of 0.7). This estimated difference was obtained from previous research examining calorie restricted diets, where 8-Isoprostane F2a decreased from 0.68 ± 0.41 to 0.44 ± 0.39 ng/mg in response to an 8-week intervention (Crujeiras et al., 2007). Assuming a 10% dropout, we will increase the sample size to 42 participants (21 in each group).
Study analysis: All variables will be tested for normal distribution prior to analyses; this will inform which statistical test will be needed to conduct analyses. Baseline variables will be compared between the two groups. All data (apart from blood sugar patterns) will be analysed as a change from baseline and compared within and between groups using ANCOVA. The continuous blood sugar patterns will be summarised into mean blood glucose and into the percentage of time under an over a specified threshold, over the two-weeks in which they are worn. Data will be compared between the two groups in the ANCOVA model.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/07/2021
Actual
Date of last participant enrolment
Anticipated
15/07/2021
Actual
Date of last data collection
Anticipated
29/10/2021
Actual
Sample size
Target
42
Accrual to date
Final
Recruitment outside Australia
Country [1] 22827 0
New Zealand
State/province [1] 22827 0
Auckland

Funding & Sponsors
Funding source category [1] 305957 0
University
Name [1] 305957 0
Auckland University of Technology
Country [1] 305957 0
New Zealand
Funding source category [2] 306459 0
Government body
Name [2] 306459 0
NZ Defence Force
Country [2] 306459 0
New Zealand
Funding source category [3] 306460 0
University
Name [3] 306460 0
Unitec Institute of Technology
Country [3] 306460 0
New Zealand
Primary sponsor type
University
Name
Auckland University of Technology
Address
Auckland University of Technology
90 Akoranga Drive
Northcote 1020
Auckland
NZ
Country
New Zealand
Secondary sponsor category [1] 306414 0
Government body
Name [1] 306414 0
NZ Defence Force
Address [1] 306414 0
NZ Defence Force
Naval base
Jim Titchener Parade, Stanley Point, Auckland 0624
Country [1] 306414 0
New Zealand

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 306199 0
Northern A Health and Disability Ethics Committee
Ethics committee address [1] 306199 0
Northern A Health and Disability Ethics Committee
Ministry of Health, Level 3,Rangitoto Room, Unisys Building, 650 Great South Road, Penrose, Auckland, 1051
Ethics committee country [1] 306199 0
New Zealand
Date submitted for ethics approval [1] 306199 0
26/03/2021
Approval date [1] 306199 0
Ethics approval number [1] 306199 0
Ethics committee name [2] 306667 0
AUT Ethics Committee
Ethics committee address [2] 306667 0
AUT Ethics Committee
55 Wellesley Street East, Auckland CBD, Auckland 1010
Ethics committee country [2] 306667 0
New Zealand
Date submitted for ethics approval [2] 306667 0
15/10/2020
Approval date [2] 306667 0
Ethics approval number [2] 306667 0
Ethics committee name [3] 306668 0
NZ Defence Force
Ethics committee address [3] 306668 0
NZ Defence Force
Naval base
Jim Titchener Parade, Stanley Point, Auckland 0624
Ethics committee country [3] 306668 0
New Zealand
Date submitted for ethics approval [3] 306668 0
22/09/2020
Approval date [3] 306668 0
Ethics approval number [3] 306668 0

Summary
Brief summary
This is a 12-week RCT to investigate three key metabolic markers in the weight loss context using two different dietary approaches: a conventional low fat approach (LF) and a carbohydrate restricted approach. The markers are: i. F2 prostanes, a marker of oxidative stress; ii. the ratio of omega 6 to omega 3 polyunsaturated fats, specifically arachinonic acid (AA) to eicosapentanoic acid (EPA); iii. , and iii. blood glucose patterning. Other outcomes will be body composition, weight, waist circumference, and visceral fat,

The hypothesis is that the carbohydrate-restricted group will show a higher AA to EPA ratio, a reduced F2 isoprostane (oxidative) response and a more even blood sugar pattern compared to the low fat group.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 103062 0
Dr Caryn Zinn
Address 103062 0
Auckland University of Technology
90 Akoranga Drive,
Northcote 1020
Auckland
Country 103062 0
New Zealand
Phone 103062 0
+6499219999
Fax 103062 0
Email 103062 0
[email protected]
Contact person for public queries
Name 103063 0
Caryn Zinn
Address 103063 0
Auckland University of Technology
90 Akoranga Drive,
Northcote 1020
Auckland
Country 103063 0
New Zealand
Phone 103063 0
+6499219999
Fax 103063 0
Email 103063 0
[email protected]
Contact person for scientific queries
Name 103064 0
Caryn Zinn
Address 103064 0
Auckland University of Technology
90 Akoranga Drive,
Northcote 1020
Auckland
Country 103064 0
New Zealand
Phone 103064 0
+6499219999
Fax 103064 0
Email 103064 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
All of the individual participant data collected during the trial, after de-identification.
When will data be available (start and end dates)?
Once the trial has been completed and after a peer-reviewed publication is been achieved. No end date.
Available to whom?
Only researchers who provide a methodologically sound proposal. This will be assessed on a case-by-case basis at the discretion of principle investogator.
Available for what types of analyses?
Only for analyses to achieve the aims in the approved proposal.
How or where can data be obtained?
Access will be subject to approvals by the principal investigator ([email protected])


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.