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Trial registered on ANZCTR

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

Titles & IDs
Public title
Investigating the influence of an oral rinse intervention, containing a taste stimuli, on participants taste perception/sensitivity.
Scientific title
Oral Rinse Intervention Study, investigating changes in detection and recognition threshold and suprathreshold intensity perception following an oral rinse containing specific tastants in generally healthy participants.
Secondary ID [1] 298186 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Taste sensitivity 312772 0
Condition category
Condition code
Oral and Gastrointestinal 311270 311270 0 0
Normal oral and gastrointestinal development and function

Study type
Description of intervention(s) / exposure
Participants will be completing four, 2-week oral rinse interventions, where they are required to rinse their mouth out with 30ml of a food grade solution, 3 times a day (directly after breakfast, lunch and dinner), for 30 seconds, participants will be instructed not to swallow the solution.
In a randomised, cross-over intervention design participants will be exposed to all four interventions in a uniquely randomised order, with a 3-week washout between each oral rinse intervention. Participants will be sent via text or email a link to a compliance survey where they will be required to record all rinses completed on that day, or any rinses missed on that day, this will be sent out between 7-8.30pm daily.
The rinses include:
- 400 mM Monopotassium Glutamate
- 400 mM Monosodium Glutamate
- 400 mM sucrose
- 400 mM sodium chloride

Participants will be provided with the solutions for the two weeks and will be instructed to keep the solutions in the fridge for the duration of the intervention, once the intervention has been completed participants can dispose of the bottles as required. Participants will complete the oral rinse intervention at home/away from the research facility.
Intervention code [1] 314421 0
Other interventions
Comparator / control treatment
There is no control intervention, due to the nature of the balanced, randomised, cross-over intervention design, participants will be their own control, and thus no control intervention rinse will be applied.
Control group

Primary outcome [1] 320012 0
Change in taste sensitivity (mM) for detection threshold (DT) and recognition threshold (RT), this is measured following ISO - Method of Investigating sensitivity of taste (ISO 3972:1991).
Timepoint [1] 320012 0
After two weeks of the intervention
Primary outcome [2] 320013 0
Change in taste intensity perception, on 100 point vertical line scale (Labelled Magnitude Scale).
Timepoint [2] 320013 0
After two weeks of the intervention
Secondary outcome [1] 370235 0
Change in umami discrimination status, based on number of correct answers in a discrimination task, this discrimination task requires participants to taste three samples containing 29mM MSG or 29mM NaCl and choose the sample that is different, this is repeated 24 times as per previously published methodology (Lugaz O1, Pillias AM, Faurion A. Chem Senses. A new specific ageusia: some humans cannot taste L-glutamate. 2002 Feb;27(2):105-15).
Timepoint [1] 370235 0
After two weeks of the intervention

Key inclusion criteria
Any participant, provided they do not meet any of the exclusion criteria.
Minimum age
18 Years
Maximum age
50 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- non smoker
- not currently pregnant
- no allergies to the food grade chemicals in the rinse
- no known taste impairments

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation not concealed, participants allocate to the next available intervention order.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation generated in consultation with a statistician using simple randomisation for example from a statistics book to ensure all possible orders obtained, due to four interventions, there are 24 possible orders for a balanced design.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
A balanced, cross-over intervention design will be followed.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Active, not 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] 26444 0
3125 - Burwood

Funding & Sponsors
Funding source category [1] 302725 0
Name [1] 302725 0
Deakin University, Centre for Advanced Sensory Science
Address [1] 302725 0
221 Burwood highway, Burwood, VIC, 3125
Country [1] 302725 0
Primary sponsor type
Deakin University, School of Exercise and Nutrition Sciences, Centre for Advanced Sensory Science.
221 Burwood highway, Burwood, VIC, 3125
Secondary sponsor category [1] 302657 0
Name [1] 302657 0
Address [1] 302657 0
Country [1] 302657 0

Ethics approval
Ethics application status
Ethics committee name [1] 303332 0
Deakin University Human Research Ethics Committee
Ethics committee address [1] 303332 0
Locked Bag 20000, Geelong, VIC 3220
Ethics committee country [1] 303332 0
Date submitted for ethics approval [1] 303332 0
Approval date [1] 303332 0
Ethics approval number [1] 303332 0

Brief summary
Investigating factors that influence taste perception provides an insight why individuals may over consume certain foods. There are a number of factors which influence taste perception, including environmental (dietary) and genetic factors. In this study we will be investigating the influence of frequent oral (mouth) exposure to certain taste stimuli on taste perception. As certain genes have been found to be associated with individual differences in taste perception, it is also of interest to investigate the role genetics has in taste perception particularly following oral exposure to certain taste stimuli. It is hypothesised that oral exposure to certain tastants will reduce participants taste sensitivity, that is make them less sensitive, to that specific tastant.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 93302 0
Prof Russell Keast
Address 93302 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 93302 0
Phone 93302 0
+61 3 924 46944
Fax 93302 0
Email 93302 0
Contact person for public queries
Name 93303 0
Miss Isabella Hartley
Address 93303 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 93303 0
Phone 93303 0
Fax 93303 0
Email 93303 0
Contact person for scientific queries
Name 93304 0
Prof Russell Keast
Address 93304 0
Deakin University, 221 Burwood Highway, Burwood, VIC, 3125
Country 93304 0
Phone 93304 0
+61 3 924 46944
Fax 93304 0
Email 93304 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
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