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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
Actions of kiwifruit and dietary fibre on bowel function in healthy adults
Scientific title
Actions of kiwifruit and dietary fibre on bowel function in healthy adults: a randomised cross-over clinical trial
Secondary ID [1] 292454 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Bowel health and function 304066 0
Condition category
Condition code
Oral and Gastrointestinal 303393 303393 0 0
Normal oral and gastrointestinal development and function
Diet and Nutrition 303394 303394 0 0
Other diet and nutrition disorders

Study type
Description of intervention(s) / exposure
This is a 17-week cross-over study. Participants will consume three treatments; 2 kiwifruit daily, one kiwifruit plus 1.25 tsp of Metamucil® daily or 2.5 tsp of Metamucil® daily. There is two week lead-in period, a three week intervention, a two week wash-out, a second three week intervention, a two week wash-out, a third three week intervention and a two week follow-up period. Venous blood samples (20 ml) will be collected at the beginning and end of the study. Bowel health and dietary intake will be assessed using faecal samples and three-day diet records. A daily bowel habit diary will be completed for 11 weeks of the trial. The trial involves 8 visits to Plant & Food Research.

At the end of each trial period, participants will return unused kiwifruit or Metamucil® to the trial coordinators as a measure of compliance. Particpants will also be directly asked whether or not they adhered to the protocol.
Intervention code [1] 298632 0
Intervention code [2] 298633 0
Treatment: Other
Comparator / control treatment
Participants will complete three interventions. The three interventions are (1) two green kiwifruit (Actinidia deliciosa var. Hayward) per day; (2) psyllium supplied as a commercially sourced preparation (Metamucil®, 2.5 teaspoons per day) given in two doses per day providing 5.0 g fibre to match the fibre content of two green kiwifruit; and (3) 1 green kiwifruit per day (Actinidia deliciosa var. Hayward) plus psyllium at half the dose ((Metamucil®, 1.25 teaspoons per day). This will allow researchers to compare bowel habits between interventions.
Control group

Primary outcome [1] 302782 0
Complete Spontaneous Bowel Movement (CSBM) Frequency (CSBM/week) as a measure of overall bowel function
Timepoint [1] 302782 0
CSBM will be measured daily during the lead-in and three intervention periods

Secondary outcome [1] 336992 0
Stool consistency as indicated by the Bristol Stool Scale
Timepoint [1] 336992 0
Measured daily during the lead-in and three intervention periods
Secondary outcome [2] 336993 0
Assessment of fructan intake as measured using a Fructan Food Frequency Questionnaire

Timepoint [2] 336993 0
At end of lead-in, end of intervention 1, end of washout 1, end of intervention 2, end of washout 2 and end of intervention 3
Secondary outcome [3] 337131 0
Assessment of diet as measured using a three-day Food Diary
Timepoint [3] 337131 0
At end of lead-in, end of intervention 1, end of washout 1, end of intervention 2, end of washout 2 and end of intervention 3

Key inclusion criteria
Healthy adults between ages of 18-65 years inclusive with a BMI between 18-35 kg/m2.
Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Potential participants will be excluded if they have any 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 cord injury, stroke).

All participants will be screened at recruitment for fasting blood glucose. Those with results great than or equal to 6.0 mmol/l will not be accepted into the trial as they are at risk of having impaired glucose tolerance, which is an exclusion criteria for the study.

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 the condition that the medication has been in use continually and that 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. The reason for excluding latex allergy is because people with this allergy are more likely to have an allergy to food including kiwifruit.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be enrolled by researcher by a face to face interview and will be given a unique identifying number (ID) for labelling all further trial data. The ID number will be provided to an independent biostatistician 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 using a randomisation table created by computer software.
Masking / blinding
Blinded (masking 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
The study is designed to detect an increase of 1.0 or more CSBM per week in healthy individuals.

An initial calculation has been completed using available data. Based on previous studies (Chan et al. 2007), the standard deviation for the primary outcome (number of CSBM per week) is 1.41. In order to detect an increase in CSBM of 1.0 per week in the study population, with 80% power and 5% significance, 16 participants are required to complete the trial. In order to allow for an expected 25% dropout, 20 subjects will be recruited.

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] 9062 0
New Zealand
State/province [1] 9062 0

Funding & Sponsors
Funding source category [1] 297022 0
Name [1] 297022 0
Plant and Food Research
Address [1] 297022 0
Batchelar Road
Palmerston North
Country [1] 297022 0
New Zealand
Primary sponsor type
Plant and Food Research
Batchelar Road
Palmerston North
New Zealand
Secondary sponsor category [1] 296032 0
Name [1] 296032 0
Address [1] 296032 0
Country [1] 296032 0

Ethics approval
Ethics application status
Ethics committee name [1] 298207 0
Health and Disability Ethics Committee
Ethics committee address [1] 298207 0
Ministry of Health
20 Aitken Street
Ethics committee country [1] 298207 0
New Zealand
Date submitted for ethics approval [1] 298207 0
Approval date [1] 298207 0
Ethics approval number [1] 298207 0

Brief summary
The proposed study will be a randomised, controlled, cross-over clinical intervention study. The cross-over design will be completed using the kiwifruit intervention of two green kiwifruit per day, compared to a positive control intervention of psyllium (2.5 teaspoons of Metamucil® per day providing 5.0 g fibre to match that fibre content of two green kiwifruit), and the combination of kiwifruit and psyllium (1 green kiwifruit per day and 1.25 teaspoons of Metamucil per day providing a total of 5.0 g of fibre).

The study duration is a total of 17 weeks; 2-week lead in, 3-week intervention, 2-week washout, 3-week intervention, 2-week washout, 3-week intervention and final 2-week follow-up. All participants will be free living and required to maintain their normal dietary and lifestyle habits for the duration of the trial.

The primary outcome measure will be quantification of CSBM (complete spontaneous bowel movement). Secondary outcome measures will include additional stool frequency measures (spontaneous bowel movements (SBM), complete bowel movements (CBM) bowel movements (BM)), and habitual dietary fibre intake.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 76338 0
Dr Christine Butts
Address 76338 0
Plant and Food Research
Batchelar Road
Palmerston North
Country 76338 0
New Zealand
Phone 76338 0
+64 6 3556147
Fax 76338 0
Email 76338 0
Contact person for public queries
Name 76339 0
Mrs Hannah Dinnan
Address 76339 0
Plant and Food Research
Private Bag 11600
Palmerston North
Country 76339 0
New Zealand
Phone 76339 0
+64 6 3530962
Fax 76339 0
Email 76339 0
Contact person for scientific queries
Name 76340 0
Dr Christine Butts
Address 76340 0
Plant and Food Research
Private Bag 11600
Palmerston North
Country 76340 0
New Zealand
Phone 76340 0
+64 6 3556147
Fax 76340 0
Email 76340 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