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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

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]

None

Universal Trial Number (UTN)

U1111-1213-7790

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Obesity

Condition category

Condition code

Diet and Nutrition

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]

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]

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]

Pre and post each three week dietary intervention

Primary outcome [2]

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]

Pre and post each 3 week dietary intervention

Primary outcome [3]

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]

Pre and post each three week dietary fibre intervention

Secondary outcome [1]

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]

Pre and post each three week dietary intervention

Secondary outcome [2]

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]

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

Sex

Both males and females

Can healthy volunteers participate?

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

29/05/2018

Actual

29/05/2018

Date of last participant enrolment

Anticipated

2/07/2018

Actual

11/09/2019

Date of last data collection

Anticipated

30/01/2019

Actual

4/01/2020

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

NSW

Recruitment postcode(s) [1]

2500 - Wollongong

Funding & Sponsors

Funding source category [1]

University

Name [1]

University of Wollongong, SMAH Small Projects Grants Scheme – 2018 Round

Address [1]

University of Wollongong
Northfields Avenue
Wollongong, NSW
2522

Country [1]

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]

Individual

Name [1]

Xu- Feng Huang

Address [1]

Illawarra Health and Medical Research Institute
Building 32, Room.305
University of Wollongong
Northfields Avenue
Wollongong NSW 2522

Country [1]

Australia

Other collaborator category [1]

Individual

Name [1]

Georgina Williams

Address [1]

Building 41, Room 228,
University of Wollongong
Northfields Ave
Wollongong NSW 2522
Australia

Country [1]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

UOW & ISLHD Health and Medical Human Research Ethics Committee

Ethics committee address [1]

Level 1, Building 20
Communications Centre
University of Wollongong 
Wollongong 2522
NSW

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

13/03/2018

Approval date [1]

26/04/2018

Ethics approval number [1]

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

A/Prof Eleanor Beck

Address

Building 41. Room 312
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW

Country

Australia

Phone

+61 2 4298 1271

Fax

[email protected]

Contact person for public queries

Name

Georgina Williams

Address

Building 41.
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW

Country

Australia

Phone

+61 2 4221 4600

Fax

[email protected]

Contact person for scientific queries

Name

Georgina Williams

Address

Building 41.
University of Wollongong
Northfields Avenue
Wollongong, 2522
NSW

Country

Australia

Phone

+61 2 4221 4600

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

No/undecided IPD sharing reason/comment

This was not specified on ethics approval

What supporting documents are/will be available?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
11089	Informed consent form	N/A			See attachment	375065-(Uploaded-01-05-2020-09-33-07)-Study-related document.docx

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

Trial Review

Documents added manually

Documents added automatically