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Trial registered on ANZCTR


Registration number
ACTRN12618000900213
Ethics application status
Approved
Date submitted
25/05/2018
Date registered
29/05/2018
Date last updated
19/03/2021
Date data sharing statement initially provided
19/03/2021
Date results information initially provided
19/03/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Dietary fibres and gut microbiome response in obese subjects
Scientific title
Dietary fibres and gut microbiome response in obese subjects
Secondary ID [1] 294833 0
None
Universal Trial Number (UTN)
U1111-1213-7790
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 307781 0
Condition category
Condition code
Diet and Nutrition 306824 306824 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This pilot project will be of crossover design with randomised order of dietary intervention in up to 20 obese subjects with anthropometry indicating metabolic risk (BMI >30 kg m-2 and waist circumference indicating metabolic risk). Four separate dietary interventions will occur, each with daily consumption of the cereal product for a 3 week period. These interventions include (a low fibre control (<1g dietary fibre), two moderate fibre cereals- sorghum and oats (3g dietary fibre) and a high fibre cereal- oat (providing 12g dietary fibre) and there will be a 3-week washout between test phases.
Intervention code [1] 301146 0
Lifestyle
Comparator / control treatment
Participants will be provided, in a randomised order,with a low fibre control cereal to consume for three weeks during the trial period. The low fibre control cereal will be rice based.
Control group
Active

Outcomes
Primary outcome [1] 305814 0
Changes in SCFA production. Blood samples will be taken from participants at the beginning and end of each trial period. Samples will be centrifuged and plasma will be stored at -80 degrees celsius. Plasma will undergo gas chromatography/mass spectrometry to determine SCFA concentrations.
Timepoint [1] 305814 0
Pre and post each three week dietary intervention
Primary outcome [2] 305815 0
Changes in gut microbiome composition. Stool samples willl be taken from participants at the beginning and end of each trial period. Samples will be taken by participants at home using OMNIGENE-GUT kits. These kits stabilise DNA for microbiome analysis to determine bacteria composition and diversity.
Timepoint [2] 305815 0
Pre and post each 3 week dietary intervention
Primary outcome [3] 305816 0
Changes in plasma LPS concentrations. Blood samples will be taken from participants at the beginning and end of each trial period. Samples will be centrifuged and plasma will be stored at -80 degrees celsius. Plasma will undergo Hycult Biotech Limulus Amebocyte Lysate assay to determine LPS concentrations.
Timepoint [3] 305816 0
Pre and post each three week dietary fibre intervention
Secondary outcome [1] 346658 0
Changes in anthropometrical measures. This will involve body weight and BMI using a digital scale and stadiometer and waist circumference using a plastic measuring tape.
Timepoint [1] 346658 0
Pre and post each three week dietary intervention
Secondary outcome [2] 347440 0
Blood Pressure. This will be measured using Omron automatic blood pressure cuff measure. This will be taken on participant arrival to each dietary counselling session.
Timepoint [2] 347440 0
Pre and post each three week dietary intervention

Eligibility
Key inclusion criteria
Overweight (BMI >25kg/m2)
Aged between 18 and 60 years
Weight stable (<3kg weight loss or gain in the past 12 months).
Minimum age
18 Years
Maximum age
60 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
-are unwilling to consume a meal comprising of cereal foods (e.g. breakfast cereal) for four 3-week periods
* smoke cigarettes
* have diabetes
* have any major illnesses
* have an allergy/intolerance to wheat or gluten or any cereals
* cannot understand English.
* Have lost or gained more than 3kg in the past 12 months
* Have taken a course of antibiotics in the past 3 months

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)
randomisation was administered by a researcher independent of the subject interface
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Permuted block randomisation
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Subject numbers are based on the primary outcome of microbiome changes with studies against a control group showing at a power of 0.8 with alpha 0.05, 10 subjects would be required to show difference in microbiome at the phylum level or 20 at a genus level, however in a crossover trial, less numbers are required. We therefore are targeting 15 subjects to complete the trial and will recruit increased recruitment will allow for dropouts.

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 in Australia
Recruitment state(s)
NSW
Recruitment postcode(s) [1] 22623 0
2500 - Wollongong

Funding & Sponsors
Funding source category [1] 299430 0
University
Name [1] 299430 0
University of Wollongong, SMAH Small Projects Grants Scheme – 2018 Round
Address [1] 299430 0
University of Wollongong
Northfields Avenue
Wollongong, NSW
2522
Country [1] 299430 0
Australia
Primary sponsor type
Individual
Name
Eleanor Beck
Address
Building 41 Room 312
University of Wollongong
Northfields Avenue
NSW 2522
Country
Australia
Secondary sponsor category [1] 298727 0
Individual
Name [1] 298727 0
Xu- Feng Huang
Address [1] 298727 0
Illawarra Health and Medical Research Institute
Building 32, Room.305
University of Wollongong
Northfields Avenue
Wollongong NSW 2522
Country [1] 298727 0
Australia
Other collaborator category [1] 280102 0
Individual
Name [1] 280102 0
Georgina Williams
Address [1] 280102 0
Building 41, Room 228,
University of Wollongong
Northfields Ave
Wollongong NSW 2522
Australia
Country [1] 280102 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 300330 0
UOW & ISLHD Health and Medical Human Research Ethics Committee
Ethics committee address [1] 300330 0
Level 1, Building 20
Communications Centre
University of Wollongong
Wollongong 2522
NSW
Ethics committee country [1] 300330 0
Australia
Date submitted for ethics approval [1] 300330 0
13/03/2018
Approval date [1] 300330 0
26/04/2018
Ethics approval number [1] 300330 0
2018/133

Summary
Brief summary
Obesity and its associated metabolic diseases are closely linked with the gut microbiome which is significantly affected by the amount and type of dietary fibre consumed. Reviews have identified broad effects on the gut microbiome with consumption of dietary fibre, but recognise that differentiation between the effects of individual fibres is required. Although fibre is referred to as a single entity in nutrient reference values and other dietary guidance systems, fibres vary significantly in chemical composition and their physico-chemical properties in turn affect their physiological actions. This research will investigate these fibres individually in order to enhance understanding of their influence in the relationship between obesity and the gut microbiome.
This pilot project will be of crossover design with randomised order of dietary intervention in up to 20 obese subjects with anthropometry indicating metabolic risk (BMI >30 kg m-2 and waist circumference indicating metabolic risk). Four separate dietary interventions will occur, each of 3 weeks (including a low fibre control, two moderate fibre cereals- sorghum and oats and a high fibre cereal- oats) and there will be a 3-week washout between test phases. We will measure effects of increased cereal fibre intake and of different cereal types, on the microbiome, body weight, percent body fat and serum levels of short chain fatty acids (SCFA) and lipopolysaccharides (LPS). SCFA levels will be modulated (higher levels of some SCFA modulated by the type of fibre) by changes in dietary fibre intake and previous research demonstrates that SCFA are part of the mechanism by which metabolic outcomes are improved. The LPS will act as a marker of toxicity which we would expect to decrease with improved diet. Using microbiome changes as the primary outcome will provide insight for ongoing studies to determine doses of fibre and types of fibre that may have positive benefits on health outcomes due to a mechanism involving the microbiome.
We expect beneficial effect of increased dietary fibre intake and reduction of aversive effects associated with obesity.

We propose that positive changes in the gut-microbiome can be detected after relatively short periods of time and that change is related to the type of fibre increased in the diet, not just the amount of dietary fibre. We hypothesise that this mechanism is associated with changes in SCFA and LPS (which has been linked with positive health outcomes).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 83318 0
A/Prof Eleanor Beck
Address 83318 0
Building 41. Room 312
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW
Country 83318 0
Australia
Phone 83318 0
+61 2 4298 1271
Fax 83318 0
Email 83318 0
eleanor_beck@uow.edu.au
Contact person for public queries
Name 83319 0
Miss Georgina Williams
Address 83319 0
Building 41.
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW
Country 83319 0
Australia
Phone 83319 0
+61 2 4221 4600
Fax 83319 0
Email 83319 0
gw659@uowmail.edu.au
Contact person for scientific queries
Name 83320 0
Miss Georgina Williams
Address 83320 0
Building 41.
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW
Country 83320 0
Australia
Phone 83320 0
+61 2 4221 4600
Fax 83320 0
Email 83320 0
gw659@uowmail.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
This was not specified on ethics approval
What supporting documents are/will be available?
Informed consent form
How or where can supporting documents be obtained?
Type [1] 11089 0
Informed consent form
Citation [1] 11089 0
N/A
Link [1] 11089 0
Email [1] 11089 0
Other [1] 11089 0
See attachment
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary