Please note that the ANZCTR website will be unavailable from 9am until 9.30am (AEST) on Monday 22nd July for website maintenance. Please be sure to log out of the system in order to avoid any loss of data. Thank you and apologies for any inconvenience caused.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR


Registration number
ACTRN12611000162910
Ethics application status
Approved
Date submitted
9/02/2011
Date registered
10/02/2011
Date last updated
27/10/2016
Type of registration
Prospectively registered

Titles & IDs
Public title
Vitamin C uptake from kiwifruit compared with a vitamin C supplement
Scientific title
Vitamin C bioavailability from kiwifruit compared with a vitamin C supplement - a randomised parallel study in men
Secondary ID [1] 253573 0
Nil
Universal Trial Number (UTN)
Nil
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Vitamin C status 261141 0
Condition category
Condition code
Public Health 259296 259296 0 0
Health promotion/education

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Arm 1 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - gold kiwifruit (half/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 2 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - chewable vitamin C tablet (45mg/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels. Arm 3 - baseline period (4 weeks) to monitor dietary intake of vitamin C; intervention period (6 weeks) - gold kiwifruit (two/day); washout period (4 weeks) to monitor return of plasma vitamin C to baseline levels.
Intervention code [1] 258002 0
Lifestyle
Intervention code [2] 258010 0
Treatment: Other
Comparator / control treatment
Arm 2 - vitamin C supplement
Control group
Active

Outcomes
Primary outcome [1] 262096 0
Measurement of vitamin C status of blood plasma by HPLC
Timepoint [1] 262096 0
Weekly for 14-16 weeks
Secondary outcome [1] 273145 0
Measurement of vitamin C status of white blood cells by HPLC
Timepoint [1] 273145 0
Before intervention and after intervention (6-8 weeks)
Secondary outcome [2] 273146 0
Measurement of vitamin C status of urine by HPLC
Timepoint [2] 273146 0
Before intervention and after intervention (6-8 weeks)
Secondary outcome [3] 273147 0
Measurement of vitamin C status of seminal fluid by HPLC
Timepoint [3] 273147 0
Before intervention and after intervention (6-8 weeks)
Secondary outcome [4] 273148 0
Measurement of vitamin C status of muscle biopsies by HPLC
Timepoint [4] 273148 0
Before intervention and after intervention (6-8 weeks)
Secondary outcome [5] 273149 0
Assessment of Profile of Mood States questionnaire
Timepoint [5] 273149 0
Before intervention and after intervention (6-8 weeks)

Eligibility
Key inclusion criteria
Male aged 18-30 years
Non-smoker
Low/below average plasma vitamin C levels (<40 uM)
Residing in Christchurch for the duration of the study
Minimum age
18 Years
Maximum age
30 Years
Gender
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Recent smoker (within previous year)
Allergy/intolerance to kiwifruit
Taking vitamin C containing supplements (within past three months)
Excessive alcohol consumption (>21 standard drinks/week)
High fruit and vegetable consumption (>5 servings/day)
Diabetes mellitus
Bleeding disorders
Obese (>35 kg/m2)
Fear of needles

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)
Participants will be enrolled following screening for low vitamin C status
Allocation to intervention will be by sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be randomised via coin toss
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Bio-availability
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment outside Australia
Country [1] 3174 0
New Zealand
State/province [1] 3174 0
Canterbury

Funding & Sponsors
Funding source category [1] 258463 0
Commercial sector/Industry
Name [1] 258463 0
Zespri International Ltd
Address [1] 258463 0
400 Maunganui Road
Mount Maunganui 3116
Country [1] 258463 0
New Zealand
Primary sponsor type
Individual
Name
Margreet Vissers
Address
University of Otago, Chirsthurch
2 Riccarton Ave
Christchurch 8140
Country
New Zealand
Secondary sponsor category [1] 257605 0
Individual
Name [1] 257605 0
Anitra Carr
Address [1] 257605 0
University of Otago, Chirsthurch
2 Riccarton Ave
Christchurch 8140
Country [1] 257605 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 260443 0
Upper South Regional Ethics Committee
Ethics committee address [1] 260443 0
250 Oxford Terrace
Christchurch 8011
Ethics committee country [1] 260443 0
New Zealand
Date submitted for ethics approval [1] 260443 0
07/02/2011
Approval date [1] 260443 0
Ethics approval number [1] 260443 0

Summary
Brief summary
Vitamin C is an essential nutrient which is not produced in humans and consequently must be obtained through dietary sources. Kiwifruit is an outstanding commonly available source of vitamin C, one serving providing about twice the recommended daily intake of the vitamin. We are proposing to investigate the uptake of vitamin C from kiwifruit compared with a vitamin C supplement using a randomised parallel groups study design. We will screen individuals for low vitamin C status and each participant will be randomised to receive either kiwifruit or a vitamin C supplement. The vitamin C status of the participant’s blood plasma will be measured regularly as an indication of dietary intake of the vitamin. Food and beverage records will also be filled out periodically to monitor the participant’s dietary intake of the vitamin. The vitamin C levels of urine, semen, white blood cells and muscle tissue will be measured at the beginning and end of the supplementation period to determine cellular accumulation and excretion of the vitamin. Overall, the proposed study will provide valuable information as to how the body accumulates and stores vitamin C, and whether or not a food source of the vitamin is preferred over a dietary supplement.
Trial website
Trial related presentations / publications
Carr AC, Bozonet SM, Pullar JM, Simcock JW, Vissers MC. A randomized steady-state bioavailability study of synthetic versus natural (kiwifruit-derived) vitamin C. Nutrients. 2013 Sep 17;5(9):3684-95.


Carr, A.C., Bozonet S.M., Pullar, J.M., Vissers, M.C.M. (2013). Mood improvement in young adult males following supplementation with gold kiwifruit, a high vitamin C food. J Nutr Sci. 2 (e24), 1-8. doi:10.1017/jns.2013.12.


Carr, A.C., Bozonet S.M., Pullar, J.M., Simcock, J.W., Vissers, M.C.M. (2013). Human skeletal muscle ascorbate is highly responsive to changes in vitamin C intake and plasma concentrations. Am J Clin Nutr. 97 (4), 800-807.
Public notes

Contacts
Principal investigator
Name 32192 0
Prof Margreet Vissers
Address 32192 0
University of Otago, Christchurch 2 Riccarton Ave Christchurch 8140
Country 32192 0
New Zealand
Phone 32192 0
64 3 364 1524
Fax 32192 0
Email 32192 0
margreet.vissers@otago.ac.nz
Contact person for public queries
Name 15439 0
Dr Anitra Carr
Address 15439 0
University of Otago, Christchurch
2 Riccarton Ave
Christchurch 8140
Country 15439 0
New Zealand
Phone 15439 0
64 3 378 6498
Fax 15439 0
Email 15439 0
anitra.carr@otago.ac.nz
Contact person for scientific queries
Name 6367 0
Prof Margreet Vissers
Address 6367 0
University of Otago, Christchurch
2 Riccarton Ave
Christchurch 8140
Country 6367 0
New Zealand
Phone 6367 0
64 3 364 1524
Fax 6367 0
Email 6367 0
margreet.vissers@otago.ac.nz

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary