Condition category
Digestive System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
How people perceive the 5 basic tastes (bitter, sweet, salty, sour and umami [savoury]) is thought to affect food preferences and choices. It is not known whether there is a link between taste perception and obesity and it would be useful to conduct research into a potential link. However, it is difficult to measure taste perception consistently across a group of people. This study aims to investigate whether educating people on the basic tastes and the taste preference test improves how consistently they are able to express their taste preferences.

Who can participate?
Healthy adults aged 18 to 80 years

What does the study involve?
Participants will be randomly allocated to one of two groups. At the first visit, all participants will be asked to taste some liquids one by one and score them for the basic tastes and how much they like tasting them. One group will receive a short explanation minimal explanation of the taste perception test, scales and preferences. The other group will receive a more in-depth education on taste preference testing. After 1 to 3 weeks, all participants will repeat the taste preference test.

What are the possible benefits and risks of participating?
There are no benefits and risks expected.

Where is the study run from?
The University of Valencia School of Medicine (Spain)

When is the study starting and how long is it expected to run for?
October 2018 to December 2019

Who is funding the study?
The University of Valencia

Who is the main contact?
José V. Sorlí,

Trial website

Contact information



Primary contact

Dr Jose V Sorli


Contact details

Avda Blasco Ibanez 15

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effect of an educational intervention on taste perception, taste test performance, and scale use on precision and validity of taste perception scales and scales taste preference: a randomized and controlled trial



Study hypothesis

The hypothesis of the study is that the perception of the 5 basic tastes (sweet, salty, bitter, acid and umami), as well as their sum in a “total taste score”, is different in different people and in addition, a lower taste perception score is associated with higher body mass index (BMI). However, the measurement of taste perception is difficult, having been described different techniques for this, including categorical scales for taste rating, as well as the more complex labelled magnitude scales (LMS) (as a continuous scale). The use of one type or another of scales, the age of the participants, their educational level and the time spent in explaining the completion of taste perception tests, will influence the taste perception score, resulting in greater or lower validity and precision of the scale used, as well as in the subsequent association between the score obtained in the taste perception taste(s) and the body mass index. In this general context, the trialists hypothesize that an intensive educational intervention explaining in great detail the types of tastes, the performance of the taste tests and the use of each type of scale (categorical or LMS), will increase the validity and precision of the scales used in comparison with a control group without intensive educational intervention (standard procedure). The trialists also hypothesize that the effect on the scale validity and precision will be greater in the use of the LMS, affecting to a lesser extent the categorical scales for the perception of taste as well as in the use of similar scales to evaluate the preferences for the different tastes.

Ethics approval

Institutional review board of Valencia University (human subjects), 14/12/2018, ref: H1544387108892

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Taste perception


Intensive educational intervention in the intervention group consisting of group and individual intervention on taste qualities, taste function, taste perception, taste tests, types of taste perception scales and taste preference scales.

In the control group a minimal explanation of the performance of taste perception test, scales and preferences will be carried out.

In both groups taste perception tests will be carried out with the same tastants and concentrations as well as with the same scales (categorical versus Labeled Magnitude Scale) will be undertaken. The tastants and concentration will be as follows: Each tastant wil be presented to subjects independently. Five series of concentrations (concentrations I, II, III, IV and V, respectively) will be used for bitter, sweet, salty, sour and umami. Six representative tastants (two tastants for bitter and one tastant for the other tastes) will be used: for PROP and PTC (0.055, 0.17, 0.55, 1.7, and 5.5 mM); for sucrose (100 mM, 150 mM, 200 mM, 300 mM and 400 mM), for NaCl (25 mM, 50 mM, 75 mM, 100 mM and 200 mM); for citric acid (1 mM, 5 mM, 10 mM, 17mM and 34 mM) and for MPG (25 mM, 50 mM, 75 mM, 100 mM and 200 mM).

Intervention type



Drug names

Primary outcome measure

1. Taste perception (for individual tastes and the total taste score) at baseline and after 1-3 weeks
2. Body mass index (BMI) at baseline and after 1-3 weeks

Secondary outcome measures

1. Taste preferences at baseline and after 1-3 weeks
2. Adherence to the Mediterranean diet measured by the 14-item Mediterranean diet adherence PREDIMED scale at baseline
3. Physical activity measured by the Minnesota physical activity questionnaire at baseline
4. Sleep quality measured by the Pittsburgh Sleep Quality Index at baseline
5. Chronotype assessed using the Horne and Östberg morningness–eveningness questionnaire (MEQ) at baseline

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Volunteers recruited from the general population
2. Both sexes
3. Between 18 and 80 years old

Participant type

Healthy volunteer

Age group




Target number of participants

200 participants randomised in two groups (100 intervention group and 100 in the control group)

Participant exclusion criteria

1. Diseased
2. Allergic or intolerance to the different substances of the tests (PROP, PTC, sucrose, NaCl, MPG)
3. Immunodeficiency or HIV-positive status
4. Liver cirrhosis or chronic renal failure
5. Serious psychiatric disorders: schizophrenia, bipolar disease, eating disorders, depression, etc
6. Any severe co-morbid condition
7. Alcohol abuse or addition
8. History of major organ transplantation
9. Concurrent therapy with immunosuppressive drugs or cytotoxic agents
10. Current treatment with systemic corticosteroids
11. Current use of weight loss medication
12. Patients with an acute infection or inflammation
13. Any other condition that may interfere with the completion of the study protocol

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

University of Valencia. School of Medicine
Avda. Blasco Ibanez 15

Trial participating centre

Instituto de Salud Carlos III. Calle Sinesio Delgado 10

Sponsor information


University of Valencia

Sponsor details

Avda. Blasco Ibanez 13

Sponsor type




Funder type


Funder name

Universitat de València

Alternative name(s)

University of Valencia, 85|86

Funding Body Type

private sector organisation

Funding Body Subtype

Universities (academic only)



Results and Publications

Publication and dissemination plan

Findings regarding the main hypothesis will be published first in international journals related to nutrition, obesity and taste. Later publications will include further secondary analyses. Posters and oral communications in related scientific meetings are planned.

IPD sharing statement
Data will not be available outside the core research group. Researchers who are interested in this study can contact the main investigator (Dr JV Sorlí, if they have any questions regarding the data or are interested in further collaborations. The participants will receive written information about what the study involves and sign a consent form before entering the study. In the informed consent form, the participant is informed that the individual level data will not be publicly avalaible.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

20/11/2019: The following changes were made to the trial record: 1. The recruitment end date was changed from 30/10/2019 to 17/12/2019. 2. The overall end date was changed from 20/12/2019 to 31/12/2019.