Fat Perception in Humans (09-0873)

Study Overview
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Brief Summary
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There are many substances naturally present in the mouth that may help us taste fat in food. Two of these substances (lipases and CD36) will be examined in this study. The presence of fat in food increases food tastiness, therefore people often over-eat high-fat foods and gain weight. The purpose of this study is to determine if blocking lipases and some genetic variations in the CD36 gene will make fatty food less tasty so that people eat less. Our hypothesis is that Orlistat and a particular gene will increase one's ability to detect fat.

Detailed Description
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Determine the effect of lipolysis inhibition in oral cavity on orosensory detection of fat in humans. Hypothesis: Orally applied Orlistat will increase detection thresholds of TAGs but not FFA in humans. To test this hypothesis we will measure triolein (a TAG) and oleic acid (a FFA) taste detection thresholds with a three-alternative forced-choice (3-AFC) ascending concentration method under two conditions (Orlistat day vs. Control day). To control for olfactory input, subjects will be assessed wearing noseclips. Determine the effect of CD36 variants on fat taste perception in humans. Hypothesis: SNPs that associate with reduced CD36 expression will be associated with higher FFA and TAG detection thresholds To test this hypothesis we will measure triolein and oleic acid taste detection thresholds in subjects who carry of the common CD36 e-SNP rs1761667 (i.e. a SNP that significantly reduces CD36 level and has a minor allele frequency of 38-48%). We expect subjects who are at least heterozygous for the expression reducing allele to have higher triolein and oleic acid taste detection thresholds compared to non-carrier subjects.

Official Title
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Inhibition of Lipolysis in Oral Cavity and Fat Perception in Humans

Conditions
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Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body Mass Index greater than 30 kg/m² Exclusion Criteria: smokers or who quit smoking less than six months ago pregnancy breastfeeding diabetes taking medications that might affect taste perception previous malabsorptive or restrictive intestinal surgery

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| rs1761667- AA genotype<br>subjects carrying the CD36 genotype rs1761667, i.e. a Single Nucleotide Polymorphism that significantly reduces CD36 level and has a minor allele frequency of 38-48%. | |
| rs1761667-GG genotype<br>subjects who are homozygous of CD36 genotype rs1761667-G allele. | |
| rs1761667-AG genotype<br>Heterozygous of CD36 gene rs1761667-A genotype. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oleic Acid Detection Level | We will measure oleic acid detection levels as a marker of subjects' ability to detect free fatty acids. Oleic acid taste detection thresholds were separately assessed using a three-alternative forced-choice (i.e. 3-AFC) ascending concentration. | Ranges from 5 days after screening to several weeks, pending availablity of participant. | 
| Triolein Detection | We will measure triolein detection levels as a marker of subjects' ability to detect triglyceride. Triolein taste detection thresholds were separately assessed using a three-alternative forced-choice (i.e. 3-AFC) ascending concentration. | Ranges from 5 days after screening to several weeks, pending availablity of participant. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obesity, orlistat, taste perception