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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Green kiwifruit and Gut Health
Scientific title
A randomised single blinded cross over trial to investigate the effect of Zespri green kiwifruit on digestive and gut health function in healthy participants and individuals with irritable bowel syndrome (constipation).
Secondary ID [1] 284470 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Constipation 291704 0
Irritable bowel syndrome with constipation 291705 0
Condition category
Condition code
Oral and Gastrointestinal 292082 292082 0 0
Inflammatory bowel disease
Diet and Nutrition 292083 292083 0 0
Other diet and nutrition disorders

Study type
Description of intervention(s) / exposure
The study duration is a total of 16 weeks; 2- week lead in, 4-week intervention, 4 week washout, 4-week intervention, and final 2-week follow-up. The cross-over design will be completed using the kiwifruit intervention (2 green kiwifruit per day (Actinidia deliciosa var. Hayward), compared to a positive control intervention of psyllium (11g of psyllium per day providing 6g fibre). Compliance to the consumption of the kiwifruit will be monitored by measuring plasma vitaman C levels over the course of the study.
Intervention code [1] 289226 0
Treatment: Other
Intervention code [2] 289227 0
Comparator / control treatment
Participants will be asked to consume 11g of Psyllium daily (mucillage) as the control for this study. This treamtent phase will be four 4 weeks. The psyllium will be supplied to participants as a powder which they can either sprinkle onto food or consume with liquid.
Control group

Primary outcome [1] 291956 0
The primary measurement of the trial is Complete Spontaneous Bowel Motion frequency (CSBM /week) as a measure of overall bowel function in constipation.
The number, or occurrence, of CSBM is recorded by all participants in a daily diary recording bowel habits.
A spontaneous bowel movement (SBM) is defined as a stool not induced by rescue medication, whereas a CSBM was defined as an SBM associated with a sensation of complete evacuation
Timepoint [1] 291956 0
CBSM will be measured daily across the 16 week study
Secondary outcome [1] 307920 0
A range of additional measures will be made via the daily diary questionnaires. There will be a series of questions related to bowel habit and function:
1. frequency of BM
Timepoint [1] 307920 0
Measured daily for the entire 16 weeks of the study.
Secondary outcome [2] 307921 0
2. ease of defaecation

Will be measured by a question in the daily diary. e.g Did you have to use any strain in order to defecate at any of the times you had a bowel movement?

This will be asked daily for the entire 16 weeks of the study
Timepoint [2] 307921 0
Measured daily through daily diary over the entire 16 weeks of the study
Secondary outcome [3] 307922 0
3. stool form (Bristol Stool Scale)
Timepoint [3] 307922 0
measured daily through Bristol Stool Scale included in the daily diary over the entire 16 weeks of the study
Secondary outcome [4] 307923 0
4.stool volume (rated scale)
Timepoint [4] 307923 0
Measured subjectively through daily diary over the entire 16 weeks of the study
Secondary outcome [5] 307924 0
Bowel transit time. Meaured in a sub group of main cohorts. 10 participants from each group of healthy, functionally constipated and IBS-C participants. Measured using SmartPill technology.
Timepoint [5] 307924 0
Measured during week two of each intervention phase (kiwifruit and pysllium treatment). Each participant measures it twice

Key inclusion criteria
Healthy group: Adult (18-65 years); BMI 18-35; Generally healthy; Normal bowel habits
Functionally constipated group: 1.Adult (18-65 years); Females will be required to declare stage of menstrual cycle during the different trial phases; BMI between 18-35; Presence of functional constipation according to ROME III diagnostic criteria for functional constipation.

IBS-C group: 1.Adult (18-65 years); Females will be required to declare stage of menstrual cycle during the different trial phases; BMI between 18-35; Presence of functional constipation according to ROME III diagnostic criteria for IBSC.

Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Individuals with alarm features associated with bowel habit (recent changes in bowel habit (<3 months), rectal bleeding, weight loss, occult blood in stools, anaemia) , anal fissures, bleeding haemorrhoids, and family history of GI cancer or IBD.
Chronic disease (cardiovascular, cancer, renal failure, previous gastrointestinal surgery (not including appendectomy or cholecystectomy), neurological conditions (e.g. multiple sclerosis, spinal chord injury, stroke).
All patients will be screened at recruitment for fasting blood glucose. Those with results greater than 7.2 mmol/l will not be accepted into the trial.
Participants with diagnosed and stable conditions requiring the use of SSRI’s (selective serotonin reuptake inhibitors), tricyclates, opiates or anti-inflammatories will be permitted into the trial on condition the medication has been in use continually and the condition has been stable for > 3 months. Similarly those with stable and controlled diabetes (> 3 months) will be permitted to participate.
Women who are pregnant, breastfeeding or planning a pregnancy in the 3 months post selection (trial period) will be excluded.
Potential participants with known kiwifruit or latex allergy will be excluded.
Potential participants using laxatives who are not prepared to stop using the laxatives for the 2 week lead-in period will be excluded.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Subjects will be enrolled by investigators folllowing a face to face interview and given a unique identifying number for labelling all further trial data. This ID number will be provided to an independent biostatisician who will randomise the participants to the treatment schedule
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
simple randomisation by using a randomization table created by a computer software (i.e. computerised sequence generation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
An initial calculation has been completed using available data. Based on a previous studies the standard deviation for the primary outcome (number of CSBM per week) is 1.41. In order to detect an increase in CSBM of 1.5 per week in the treatment group compared to the control group, with 90% power and 5% significance, 16 subjects are required to complete the trial. In order to account for an expected 25% dropout, 20 subjects will be recruited for each of three subject populations, or a total of 60 subjects. Further statistical analysis will be done by an independent statisitican. Statistical analysis will describe the relationship between the consumption of kiwifruit and the parameters of bowel habit and digestive comfort measured. In addition the analysis will compare the effects of the 2 treatments (kiwifruit and psyllium), and determine the effects of these treatments in all groups (healthy, FBC and IBS-C).
P values =0.05 will be considered significant.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 6018 0
New Zealand
State/province [1] 6018 0
Country [2] 6024 0
New Zealand
State/province [2] 6024 0

Funding & Sponsors
Funding source category [1] 289119 0
Commercial sector/Industry
Name [1] 289119 0
Zespri International Ltd
Address [1] 289119 0
40 Maunganui Road
Mt Maunganui
New Zealand 3116
Country [1] 289119 0
New Zealand
Primary sponsor type
Commercial sector/Industry
Zespri International
40 Maunganui Road
Mt Maunganui
New Zealand 3116
New Zealand
Secondary sponsor category [1] 287781 0
Name [1] 287781 0
Address [1] 287781 0
Country [1] 287781 0
Other collaborator category [1] 277923 0
Government body
Name [1] 277923 0
New Zealand Institute for Plant & Food Research Ltd
Address [1] 277923 0
Canterbury Agricultural and Science Centre
Gerald Street
Christchurch 8140
Country [1] 277923 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 290899 0
Health and Disability Council
Ethics committee address [1] 290899 0
Ministry of Health
No 1 The Terrace
PO Box 5013
Wellington 6145
Ethics committee country [1] 290899 0
New Zealand
Date submitted for ethics approval [1] 290899 0
Approval date [1] 290899 0
Ethics approval number [1] 290899 0

Brief summary
Constipation is a common problem affecting up to 20% of the World’s population. Laxative treatment for this condition is not without side effects and currently, there is a need for natural and safe alternatives. The consumption of Kiwifruit is frequently used to treat constipation and digestive discomfort in New Zealand. Clinical trials in this area are limited but some have shown significant improvements in digestive health (stool frequency, reduced constipation and well being) in both healthy and constipated individuals as well as those suffering from irritable bowel syndrome. This study aims to examine the effect of daily consumption of two green kiwifruit in healthy individuals and in individuals with functional constipation and IBS as part of their everyday lifestyle to determine if the product is effective at improving bowel regularity, digestive discomfort, digestive health and function and gut health. It will compare the efficacy of kiwifruit with psyllium (mucilage), a bowel bulking agent that has been shown to be an effective treatment for constipation. The trial will be a randomized, single blinded cross over study where participants will consume either two green kiwifruit daily for four weeks or 11g psyllium powder for four weeks. There will be a four week washout period in between and then the participants will swap over treatments for a further four weeks. The trial will start and finish with a two week washout period. Participants will be asked to complete a daily study diary (either online or by hand) to record daily bowel movement and general wellbeing during the study. Faecal and blood samples will be collected at the beginning of the trial and at the end of each treatment period. Participants will also be asked to complete a questionnaire relating to bowel health at these time points.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 47878 0
A/Prof Richard Gearry
Address 47878 0
Gastroentetrology and Endoscopy Specialists
Level 1, 40 Stewart Street
Christchurch 8011
Country 47878 0
New Zealand
Phone 47878 0
64 3 378 6236
Fax 47878 0
64 3 378 6299
Email 47878 0
Contact person for public queries
Name 47879 0
Ms Sarah Eady
Address 47879 0
Plant & Food Research
PO Box 4704
Christchurch 8140
Country 47879 0
New Zealand
Phone 47879 0
64 3 3259671
Fax 47879 0
64 3 325 2074
Email 47879 0
Contact person for scientific queries
Name 47880 0
Ms Sarah Eady
Address 47880 0
Plant & Food Research
PO Box 4704
Christchurch 8140
Country 47880 0
New Zealand
Phone 47880 0
64 3 3259671
Fax 47880 0
64 3 325 2074
Email 47880 0

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