Please note the ANZCTR will be unattended from Friday 24 December 2021 for the holidays. The Registry will re-open on Monday 17 January 2022. Submissions and updates will not be processed during that time.

For new and updated trial submissions, we are processing trials as quickly as possible and appreciate your patience. We recommend submitting your trial for registration at the same time as ethics submission.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Measuring the impact of dietary change on human gut microbial communities
Scientific title
Microbial Shift Analysis to measure the impact of dietary change on human gut microbial communities
Secondary ID [1] 297213 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Gut microbe composition 311258 0
Condition category
Condition code
Diet and Nutrition 309881 309881 0 0
Other diet and nutrition disorders

Study type
Description of intervention(s) / exposure
Low-fibre diet (average daily approx. 18 g) versus high-fibre diet (average daily approx. 40 g). As examples of how the two diets vary:
Low-fibre/high-fibre; white rice/barley, white bread/weetbix, cantaloupe/pear, pizza/lentils, rice crackers/ryvita, lasagne/ratatouille, sponge cake/nuts
Food (intervention) prepared (provided) and delivered by researcher trained in safe-food preparation and handling. Diet designed by dietitians with a minimum of 5 years of experience.
Delivery of food is face-to-face individually. Participants will be provided with a notepad to diary any food not consumed and if additional food was consumed.
The number of times is daily for three consecutive days in the first week and repeated in the second week for a total of 6 x 15 minute visits. All participants will have the low-fibre diet in the first week and the high-fibre diet in the second week.
Intervention code [1] 313463 0
Treatment: Other
Comparator / control treatment
There are two diets being compared. Both dietary changes are compared to the baseline at day of commencement. This analysis determines positive and negative shifts from baseline.
Control group

Primary outcome [1] 318827 0
Change in species abundance from base line at Day 1 to daily for two days following commencement of diet. The species abundance is measured by sequencing the faecal samples provided daily by the participants. The tool used is novel and is based on an algorithm that determines shift directions using a excel spread sheet. The primary outcome would be measured shifts consistent with species associated with either low-fibre or high-fibre diets.
Timepoint [1] 318827 0
Timepoints are 0, 24 hours after commencement of diet and 48 hours after commencement of diet.
Secondary outcome [1] 366169 0
Timepoint [1] 366169 0
Not required

Key inclusion criteria
Men and women aged between 18 and 65 years and in good health
Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Pregnancy,
• A history of diabetes or other hormone diseases
• A history of abdominal surgery
• A current smoker
• Alcohol consumption exceeding more than two units of alcohol per day for men and more than one unit per day for women (regular alcohol consumption above this may be associated with adverse outcomes for gastrointestinal health)
• Currently suffering from a decreased appetite
• Currently suffering from nausea or vomiting
• Currently suffering from abdominal pain
• Currently suffering from light headedness, shakiness or weakness
• Currently suffering from any chronic condition
• Currently suffering from high blood pressure
• Current participation in a clinical trial (Note: If yes, this is only an exclusion if other trial involves taking a drug or another intervention)

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Individuals will receive a low-fibre diet for 3 days in week 1 and a high fibre diet for 3 days in week 2
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
This is a pilot study to determine whether individuals on a low-fibre diet have a negative shift (a shift to predominance of microorganisms with known associations with low-fibre diets) compared to a positive shift (a shift to predominance of microorganisms with known associations with high-fibre diets). The species showing shifts will be added and graphed as positive or negative on a graph. This simplified visualisation is being trialled to help the public understand how changing their diet either positively or negatively influences their gut communities.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 25471 0
3083 - Bundoora

Funding & Sponsors
Funding source category [1] 301762 0
Name [1] 301762 0
RMIT University
Address [1] 301762 0
GPO Box 2476 Melbourne Victoria 3000
Country [1] 301762 0
Primary sponsor type
Associate Professor Danilla Grando
School of Science, RMIT University, Bundoora Campus, GPO Box 71, Bundoora, Victoria, 3083
Secondary sponsor category [1] 301506 0
Name [1] 301506 0
Address [1] 301506 0
Country [1] 301506 0

Ethics approval
Ethics application status
Ethics committee name [1] 302480 0
RMIT University Human Research Ethics Committee
Ethics committee address [1] 302480 0
Human Research Ethics Committee (HREC)
Research and Innovation office
RMIT University
124 LaTrobe Street
Melbourne, Victoria, 3000
Ethics committee country [1] 302480 0
Date submitted for ethics approval [1] 302480 0
Approval date [1] 302480 0
Ethics approval number [1] 302480 0

Brief summary
Aims: This project is to verify a proposed new reporting tool for determining changes in human gut communities (gut microbiome) after dietary interventions.
Theory: The inclusion of fibre in the diet is associated with gut health. This is because fibre reaches the large intestine and feeds the resident microorganisms. These microorganisms in turn produce substances that benefit human health such as short-chain fatty acids. However the production of these substances varies with the types of organisms present and this in turn is dependent on the types of foods consumed. We can see these changes when different diets are consumed and these changes occur within a day of changing a diet. This gives us a valuable tool to determine which foods produce beneficial changes. However current methods of reporting changes to the microbiome are overly complex and do not provide a picture of changing gut communities that is readably visualised or rendered in a format understandable to lay persons wishing to understand how the foods they consume affect their gut communities.
Methodology: The current project seeks volunteers to consume low and high fibre diets and collect a swab from their first daily faecal sample. The swab will be analysed to determine the relative abundance of each type of bacteria by modern sequencing techniques. The abundance of each type of bacteria will be compared to their base line sample, collected before they start the diet, Each type of bacteria has known associations with low-fibre or high fibre and the total number of types showing positive shifts in abundance will be tallied and graphed against those showing negative shifts. It is hoped that this new simplified way of reporting changes associated with diets will help people better visualise the important benefits of changing their diet through the effects seen on changing the gut community.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 90366 0
A/Prof Danilla Grando
Address 90366 0
School of Science RMIT University
Building 223 Level 1, Bundoora Campus RMIT University
Plenty Road, Bundoora, Victoria, 3083
Country 90366 0
Phone 90366 0
Fax 90366 0
Email 90366 0
Contact person for public queries
Name 90367 0
A/Prof Danilla Grando
Address 90367 0
School of Science RMIT University
Building 223 Level 1, Bundoora Campus RMIT University
Plenty Road, Bundoora, Victoria, 3083
Country 90367 0
Phone 90367 0
Fax 90367 0
Email 90367 0
Contact person for scientific queries
Name 90368 0
A/Prof Danilla Grando
Address 90368 0
School of Science RMIT University
Building 223 Level 1, Bundoora Campus RMIT University
Plenty Road, Bundoora, Victoria, 3083
Country 90368 0
Phone 90368 0
Fax 90368 0
Email 90368 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
The individual tables showing species abundances for each sample. However individuals cannot be identified from this data. Individuals will receive a simple analysis showing the number of species that have moved in a high-fibre direction or a low-fibre direction, for each time they have a dietary intervention.
When will data be available (start and end dates)?
The data will be made available at the time of publication as a table appended to the publication. It remains available in perpetuity.
Available to whom?
Available to all those reading the publication.
Available for what types of analyses?
Available for analysis of faecal microbial population types in healthy humans.
How or where can data be obtained?
Through publication of the tables of abundances of key microbial species.
What supporting documents are/will be available?
Study protocol
Informed consent form
Ethical approval
How or where can supporting documents be obtained?
Type [1] 1165 0
Study protocol
Citation [1] 1165 0
Link [1] 1165 0
Email [1] 1165 0
Other [1] 1165 0
Type [2] 1166 0
Informed consent form
Citation [2] 1166 0
Link [2] 1166 0
Email [2] 1166 0
Other [2] 1166 0
Type [3] 1167 0
Ethical approval
Citation [3] 1167 0
Link [3] 1167 0
Email [3] 1167 0
Other [3] 1167 0
Summary results
No Results