An observational study in Dysgeusia, sponsored by University of Cagliari. Completed at 1 site in Italy. Open to participants aged 20 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2018-12-21.
Sponsored by University of Cagliari · Observational
The investigators evaluate the possible association of PROP taste with gustin gene polymorphism rs2274333 (A/G), salivary zinc ion concentration and BMI. In addition, it has also been evaluated PROP taste sensitivity by recording monophasic potentials from the tongue.
The investigators evaluate the possible association of PROP taste with gustin gene polymorphism rs2274333 (A/G), salivary zinc ion concentration and BMI.
Furthermore, we apply direct measures of the gustatory system activation following stimulation with PROP, obtained by electrophysiological recordings from the tongue of subjects classified for taster status, genotyped for the specific receptor gene (TAS2R38), and in which papilla density was determined.
52 studies on the registry are indexed under Dysgeusia; 12 are open to participants now.
This study's enrollment of 170 is above the median of 104 across 22 observational studies indexed under Dysgeusia.
Browse Dysgeusia studies →University of Cagliari is the lead sponsor of 85 studies on the registry; 17 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 1 (17%) have results posted.
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Seventy-five non-smoking volunteers (28 men and 47 women) were recruited for the study. Participants between 20-30 years were eligible for the study. Thresholds for the 4 basic tastes were evaluated in all subjects in order to rule out any gustatory impairment. The volunteers showed no variation of body weight > 5 kg over the last 3 mo. They were not following a prescribed diet or using medications that might interfere with taste perception; none had food allergies. They were assessed for cognitive eating behaviours using the Three-Factor Eating Questionnaire
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
PROP Sensitive and non sensitive individuals are defined as "Tasters" and "Non-tasters", respectively. Taster are further divided in "Super-taster" who perceived PROP as extremely bitter and "Medium tasters" who perceived PROP as moderately bitter.
Association Between Gustin Gene Polymorphism and PROP Sensitivity
We examine associations between PROP status and the polymorphism rs2274333 (A/G) of the gene that codify for the salivary protein, gustin/CA6, Which has been suggested as a trophic factor that promotes growth and development of taste buds by acting on taste bud stem cells. The intensity of taste perception evoked by PROP and NaCl solutions was estimated to evaluate PROP taster status and molecular analysis of the gustin gene polymorphism was performed in individuals classified by PROP status using PCR techniques.
Time frame: 7 months
Association Between PROP Sensitivity and Saliva Zinc Ion Concentration
Since the enzymatic function of gustin (CA6) depends upon the presence of Zn at its active site we measured the salivary zinc ion concentration in subjects classified as super-taster, medium taster and non-taster.The salivary Zn2+ concentration was measured with a QuantiChromTM zinc Assay kit (Gentaur, Brussels, Belgium) where the color intensity is directly proportional to the Zn2+ concentration in the sample.
Time frame: 7 months
Association Between PROP Sensitivity and BMI
Since individual ability to taste PROP may be correlated with BMI, we determined BMI (kg/m\^2) in subjects classified as super-taster, medium taster and non-taster.Weight (kg) and height (m) were recorded for each subject.
Time frame: 7 months
Electrophysiological Recordings From the Tongue for the Objective Evaluation of Individual Variations of 6-n-propylthiouracil (PROP) Sensitivity
electrophysiological recordings from the tongue of 43 subjects classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and genotyped for the specific receptor gene, TAS2R38. Density of fungiform papillae was also determined in each subject. The biopotentials were recorded by means of differential electrophysiological derivations between two silver electrodes, one in contact with the ventral surface of the tongue and one in perfect adhesion with the dorsal surface.
Time frame: 1 year
Association Between PROP Sensitivity and Fungiform Papilla Density
43 subjects were classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and density of fungiform papillae was determined in each subject.
Time frame: 6 months
Taste Perception of Sweet, Sour, Salty, Bitter and Umami and Changes Due to L-Arginine Supplementation, as a Functin of Genetic Ability to Taste PROP.
Taste perception was assessed by testing the ability to recognize, and the responsiveness to, representative solutions of the five taste qualities, also when supplemented with L-Arg, in subjects classified as PROP-tasters.
Time frame: 8 months
| Milestone | Super Tasters | Medium Tasters | Non Tasters |
|---|---|---|---|
| Started | 50 | 70 | 50 |
| Completed | 27 | 28 | 20 |
| Not completed | 23 | 42 | 30 |
We examine associations between PROP status and the polymorphism rs2274333 (A/G) of the gene that codify for the salivary protein, gustin/CA6, Which has been suggested as a trophic factor that promotes growth and development of taste buds by acting on taste bud stem cells. The intensity of taste perception evoked by PROP and NaCl solutions was estimated to evaluate PROP taster status and molecular analysis of the gustin gene polymorphism was performed in individuals classified by PROP status using PCR techniques.
| percentage of participants | Super Tasters | Medium Tasters | Non Tasters |
|---|---|---|---|
| Genotype AA | 85.19 | 50.99 | 25.00 |
| Genotype AG | 14.81 | 35.71 | 20 |
| Genotype GG | 0 | 14.29 | 55 |
| Allele A | 92.59 | 67.86 | 35 |
| Allele G | 7.40 | 32.14 | 65 |
Since the enzymatic function of gustin (CA6) depends upon the presence of Zn at its active site we measured the salivary zinc ion concentration in subjects classified as super-taster, medium taster and non-taster.The salivary Zn2+ concentration was measured with a QuantiChromTM zinc Assay kit (Gentaur, Brussels, Belgium) where the color intensity is directly proportional to the Zn2+ concentration in the sample.
| microg/dl | Super-tasters | Medium Tasters | Non-tasters |
|---|---|---|---|
| Association Between PROP Sensitivity and Saliva Zinc Ion Concentration | 57.3 ± 13 | 89.5 ± 17.2 | 149.64 ± 26.4 |
Since individual ability to taste PROP may be correlated with BMI, we determined BMI (kg/m\^2) in subjects classified as super-taster, medium taster and non-taster.Weight (kg) and height (m) were recorded for each subject.
| Kg/m^2 | Super-tasters | Medium Tasters | Non-tasters |
|---|---|---|---|
| Association Between PROP Sensitivity and BMI | 20.3 ± 0.48 | 20.76 ± 0.58 | 22.58 ± 0.84 |
electrophysiological recordings from the tongue of 43 subjects classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and genotyped for the specific receptor gene, TAS2R38. Density of fungiform papillae was also determined in each subject. The biopotentials were recorded by means of differential electrophysiological derivations between two silver electrodes, one in contact with the ventral surface of the tongue and one in perfect adhesion with the dorsal surface.
| mV | Super-Taster | Medium Taster | Non Taster |
|---|---|---|---|
| Electrophysiological Recordings From the Tongue for the Objective Evaluation of Individual Variations of 6-n-propylthiouracil (PROP) Sensitivity | 97,08867 ± 6,538191 | 75,42000 ± 6,538191 | 48,48231 ± 7,023144 |
43 subjects were classified for their taste sensitivity to 6-n- propyltiouracil (PROP) and density of fungiform papillae was determined in each subject.
| No./cm2 | Super-tasters | Medium Tasters | Non-tasters |
|---|---|---|---|
| Association Between PROP Sensitivity and Fungiform Papilla Density | 51.66 ± 5.25 | 33.49 ± 5.26 | 18.53 ± 7.023 |
Taste perception was assessed by testing the ability to recognize, and the responsiveness to, representative solutions of the five taste qualities, also when supplemented with L-Arg, in subjects classified as PROP-tasters.
| Participants | Primary Taste Quality | Primary Taste Quality Supplemented With L-Arg |
|---|---|---|
| sucrose — Undet Threshold | 18 | 2 |
| sucrose — Correct identification | 40 | 20 |
| sucrose — Incorrect teste response | 6 | 42 |
| NaCl — Undet Threshold | 1 | 1 |
| NaCl — Correct identification | 52 | 41 |
| NaCl — Incorrect teste response | 11 | 22 |
| Citric Acid — Undet Threshold | 5 | 4 |
| Citric Acid — Correct identification | 49 | 47 |
| Citric Acid — Incorrect teste response | 10 | 13 |
| caffeine — Undet Threshold | 6 | 6 |
| caffeine — Correct identification | 56 | 56 |
| caffeine — Incorrect teste response | 2 | 2 |
| MSG — Undet Threshold | 7 | 0 |
| MSG — Correct identification | 26 | 33 |
| MSG — Incorrect teste response | 31 | 31 |
Collected over 7 months. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Super Tasters | — | 0/27 (0%) | 0/27 (0%) |
| Medium Tasters | — | 0/28 (0%) | 0/28 (0%) |
| Non Tasters | — | 0/20 (0%) | 0/20 (0%) |
Caucasian and were originally from Sardinia, Italy. Participants between 20-30 years were eligible for the study.
| Age, Categorical(Participants) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| <=18 years | 0 | 0 | 0 | 0 |
| Between 18 and 65 years | 50 | 70 | 50 | 170 |
| >=65 years | 0 | 0 | 0 | 0 |
| Age, Continuous(years) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| Mean | 25 ± 7 | 25 ± 8 | 25 ± 6 | 25 ± 7 |
| Sex: Female, Male(Participants) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| Female | 35 | 40 | 34 | 109 |
| Male | 15 | 30 | 16 | 61 |
| Race (NIH/OMB)(Participants) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 | 0 |
| Black or African American | 0 | 0 | 0 | 0 |
| White | 50 | 70 | 50 | 170 |
| More than one race | 0 | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 | 0 |
| Region of Enrollment(participants) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| Italy | 50 | 70 | 50 | 170 |
| healthy volunteers(participants) | Super Tasters | Medium Tasters | Non Tasters | Total |
|---|---|---|---|---|
| Number | 50 | 70 | 50 | 170 |
Plan to share: Undecided — Data of this study are available from the principal investigator of this study upon request
The record gives a start of Oct 2009, a primary completion of Dec 2009 and a completion of Jun 2016. It does not say whether these dates are actual or estimated.
Results were first posted in Dec 2016, 7 years after primary completion.
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This study is completed, as verified in Dec 2018. You cannot join it, but the record below documents what was studied.
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University of Cagliari