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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
Can a high fibre diet reduce the amount of insulin the body needs to process the sugar consumed in meals?
Scientific title
Can supplemented dietary fibre improve insulin sensitivity in obese adolescents?
A randomized cross-over trial of a high fibre isocaloric diet compared to an isocaloric diet alone in a secondary school community with a high incidence of obesity.
Secondary ID [1] 280592 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Insulin resistance in a population with a high rate of obesity 251979 0
Condition category
Condition code
Metabolic and Endocrine 252168 252168 0 0

Study type
Description of intervention(s) / exposure
Participants will be randomized to recieve 6g per day psyllium or 6g/d potato starch placebo for 6 weeks on each intervention. Psyllium and placebo will be given as 6g/day as 12 x 500mg capsules, with participants instructed to consume these at once or in divided doses with a large glass of water. After 6 weeks participants will washout for 2 weeks before starting 6 weeks on the opposite intervention.
Intervention code [1] 241388 0
Treatment: Drugs
Comparator / control treatment
While on placebo or psyllium, both groups with be able to eat a normal diet.A diet recall questionaire will be given to both groups after randomization, to ensure that the groups are similar in terms of calorie intake, and the percent energy derived from fat, carbohydrate, protein, and that they have a similar background fibre intake The intervention is supplemented fibre or placebo as described above
Control group

Primary outcome [1] 253043 0
Insulin sensitivity. This will meaured through the matsuda method which is the best model to the gold standard euglycaemic clamp. This involved overnight fasting, with a oral glucose tolerance test, with measurements at 0min, 30 min, 60, 90 and 120 of serum insulin and glucose. That matsuda index calculation gives an insulin sensitivity score.
Equipment will be IV cannulation, and syringes to draw the venous samples at the time points as described above. The Liggins Institute has an in house assay for insulin levels.
Timepoint [1] 253043 0
Baseline, 6 week cross over, and completion (14 weeks)
Secondary outcome [1] 257856 0
Body Mass Index
Timepoint [1] 257856 0
Baseline, 6 week cross over, and completion (14 weeks)
Secondary outcome [2] 257857 0
Blood pressure. This will be through 24hour ambulatory blood pressure monitoring.
Timepoint [2] 257857 0
Baseline, 6 week cross over, and completion (14 weeks)

Key inclusion criteria
15 - 16 year old males from low socio-economic areas.
Minimum age
15 Years
Maximum age
16 Years
Can healthy volunteers participate?
Key exclusion criteria
Receiving medications that influence insulin sensitivity (SI) (incluing oral steroids and metformin).
Genetic conditions, (Turner, Downs or Prader-Willi syndrome).
Coeliac disease or other malabsorption disorders.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomization by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomization by using a table created by computer software.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint/s
Statistical methods / analysis

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] 2259 0
New Zealand
State/province [1] 2259 0

Funding & Sponsors
Funding source category [1] 243853 0
Name [1] 243853 0
University of Auckland / Liggins Institute
Country [1] 243853 0
New Zealand
Primary sponsor type
University of Auckland / Liggins Institute
The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
New Zealand
Secondary sponsor category [1] 237202 0
Name [1] 237202 0
Address [1] 237202 0
Country [1] 237202 0

Ethics approval
Ethics application status
Ethics committee name [1] 243976 0
Northern Regional Y Ethic Committee
Ethics committee address [1] 243976 0
Ethics committee country [1] 243976 0
Date submitted for ethics approval [1] 243976 0
Approval date [1] 243976 0
Ethics approval number [1] 243976 0

Brief summary
The purpose of the study is to formally assess the impact of fibre alone on insulin sensitivity, and if this is achieved independently of weight loss. Fibre will be givenas a supplement, without altering other aspects of the diet. The hypothesis is that the properties of fibre can benefit insulin senstivity independently of weight loss, clarifying its role in dietary interventions for overweight, and normal weight insulin resistant people. We expect the effect to be greatest in the obese population.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 30367 0
Address 30367 0
Country 30367 0
Phone 30367 0
Fax 30367 0
Email 30367 0
Contact person for public queries
Name 13614 0
martin de Bock
Address 13614 0
3A/10 Laxon Tce
Country 13614 0
New Zealand
Phone 13614 0
+64 211826579
Fax 13614 0
Email 13614 0
Contact person for scientific queries
Name 4542 0
martin de Bock
Address 4542 0
3A/10 Laxon Tce
Country 4542 0
New Zealand
Phone 4542 0
Fax 4542 0
Email 4542 0

No information has been provided regarding IPD availability

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
SourceTitleYear of PublicationDOI
Dimensions AIPsyllium Supplementation in Adolescents Improves Fat Distribution & Lipid Profile: A Randomized, Participant-Blinded, Placebo-Controlled, Crossover Trial2012https://doi.org/10.1371/journal.pone.0041735
N.B. These documents automatically identified may not have been verified by the study sponsor.