Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12621000755831
Ethics application status
Approved
Date submitted
12/05/2021
Date registered
16/06/2021
Date last updated
20/09/2022
Date data sharing statement initially provided
16/06/2021
Date results information initially provided
20/09/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
The effect of vitamin C from kiwifruit on human immune cell function
Scientific title
The effect of vitamin C from kiwifruit on human immune cell cytokine responses in young adults aged 18 - 35 years.
Secondary ID [1] 303545 0
Nil known
Universal Trial Number (UTN)
U1111-1265-3453
Trial acronym
Linked study record
Nil known

Health condition
Health condition(s) or problem(s) studied:
Vitamin C nutritional status 321906 0
Immune health 321907 0
Condition category
Condition code
Inflammatory and Immune System 319634 319634 0 0
Normal development and function of the immune system
Diet and Nutrition 319635 319635 0 0
Other diet and nutrition disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This trial is a randomised human intervention study to determine the effect of dietary supplementation with 2 SunGold kiwifruit per day or placebo tablet on the function of mononuclear immune cells (monocytes and lymphocytes). We will screen prospective participants for low plasma vitamin C status (likely due to low daily fruit and vegetable intake) and will randomly allocate the enrolled participants to either a daily kiwifruit intervention or a placebo tablet. The period of the intervention is 4 weeks.

Adherence to the assigned condition will be monitored by laboratory testing of blood plasma vitamin C status at baseline, mid-point at end of the intervention period, and by quantifying fruit/tablet return.
Intervention code [1] 320549 0
Treatment: Other
Comparator / control treatment
This is a parallel arms study with an intervention group (two Sungold kiwifruit per day) or a control (fruit-flavoured placebo chewable tablet).
Control group
Placebo

Outcomes
Primary outcome [1] 327497 0
Cytokine release by peripheral blood mononuclear cells in response to inflammatory challenge, before and after intervention..
Timepoint [1] 327497 0
At baseline and four weeks post-intervention.
Primary outcome [2] 327810 0
Vitamin C levels in peripheral blood mononuclear cells
Timepoint [2] 327810 0
At baseline, at trial midpoint (2 weeks post-intervention) and 4 weeks post intervention.
Primary outcome [3] 327811 0
Plasma vitamin C status
Timepoint [3] 327811 0
At baseline, at midpoint (2 weeks post-interventions) and at 4 weeks post intervention.
Secondary outcome [1] 395409 0
Determination of changes in gene expression in a subset of peripheral blood mononuclear cell samples following kiwifruit intake.
Timepoint [1] 395409 0
At baseline and 4 weeks post-intervention
Secondary outcome [2] 396677 0
Effect of kiwifruit intervention on susceptibility to respiratory illness, monitored by symptom survey.
Timepoint [2] 396677 0
Up to 12 weeks beyond the end of intervention period.

Eligibility
Key inclusion criteria
Inclusion criteria (all required): Males or females 18-65 years; Plasma vitamin C levels <40 µmol/L at baseline.
Minimum age
18 Years
Maximum age
65 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Exclusion criteria (one required); Taking prescription medication (within past three months); Allergy/intolerance to kiwifruit; Daily smoker: Taking vitamin C supplements (within past three months); High fruit/juice & vegetable consumption (5 or more servings/day); Excessive alcohol consumption (more than 21 standard drinks/week); Diabetes mellitus; Bleeding disorders; Fear of needles.

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 by computer-generated sequence.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using computerised sequence generation.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s

Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Comparative analysis of pre- and post-intervention samples.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
16/06/2021
Actual
16/06/2021
Date of last participant enrolment
Anticipated
30/07/2021
Actual
12/11/2021
Date of last data collection
Anticipated
22/10/2021
Actual
17/12/2021
Sample size
Target
40
Accrual to date
Final
40
Recruitment outside Australia
Country [1] 23703 0
New Zealand
State/province [1] 23703 0
Canterbury

Funding & Sponsors
Funding source category [1] 307969 0
University
Name [1] 307969 0
University of Otago, Christchurch
Country [1] 307969 0
New Zealand
Primary sponsor type
University
Name
University of Otago, Christchurch
Address
PO Box 4345, Christchurch 8140,
Country
New Zealand
Secondary sponsor category [1] 308685 0
University
Name [1] 308685 0
University of Otago, Dunedin
Address [1] 308685 0
PO Box 56, Dunedin 9054
Country [1] 308685 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 307963 0
Central Health and Disability Ethics Committee
Ethics committee address [1] 307963 0
Ministry of Health, 133 Molesworth Street, Thornton, Wellington 6011
Ethics committee country [1] 307963 0
New Zealand
Date submitted for ethics approval [1] 307963 0
Approval date [1] 307963 0
10/05/2021
Ethics approval number [1] 307963 0
21/CEN/104

Summary
Brief summary
There is widespread belief in the general population that vitamin C supports the immune system, and claims along this line are frequently encountered, including on marketing promoting commercially available dietary supplements. One of the main drivers of this interest is that leukocytes accumulate the vitamin to high intracellular concentrations, signalling an important role for it in these cells.

We will recruit individuals with low vitamin C status as indicated by a plasma vitamin C level <40 µmol/L. Participants will be randomised to be supplemented with two Sungold kiwifruit per day or a placebo tablet per day for four weeks. Two kiwifruit is equivalent to ~250 mg vitamin C per day and is sufficient to achieve plasma saturation within one week of beginning supplementation.

Blood samples will be taken before and after the intervention period to monitor plasma vitamin C status, white blood cell vitamin C levels and white blood cell immune functions.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 109062 0
Prof Margreet Vissers
Address 109062 0
Department of Pathology and Biomedical Science, University of Otago, Christchurch PO Box 4345, Christchurch, 8140.
Country 109062 0
New Zealand
Phone 109062 0
+64 3 364 1524
Fax 109062 0
Email 109062 0
margreet.vissers@otago.ac.nz
Contact person for public queries
Name 109063 0
Margreet Vissers
Address 109063 0
Department of Pathology and Biomedical Science, University of Otago, Christchurch, PO Box 4345, Christchurch, 8140.
Country 109063 0
New Zealand
Phone 109063 0
+64 3 364 1524
Fax 109063 0
Email 109063 0
margreet.vissers@otago.ac.nz
Contact person for scientific queries
Name 109064 0
Margreet Vissers
Address 109064 0
Department of Pathology and Biomedical Science, University of Otago, Christchurch PO Box 4345, Christchurch 8140.
Country 109064 0
New Zealand
Phone 109064 0
+64 3 364 1524
Fax 109064 0
Email 109064 0
margreet.vissers@otago.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
De-identified results data.
When will data be available (start and end dates)?
From three months and up to five years after publication of results.
Available to whom?
Researchers who provide a methodologically sound proposal, on a case-by-case basis at the discretion of Primary Sponsor.
Available for what types of analyses?
Analyses that further the aims of the study, and meta-analyses, with permission from the PI.
How or where can data be obtained?
Access subject to approvals by Principal Investigator, together with a requirement to sign a data access agreement. Contact details for PI: Prof Margreet Vissers, Email: margreet.vissers@otago.ac.nz


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.