Fat Perception in Humans (09-0873) (OT)

Inhibition of Lipolysis in Oral Cavity and Fat Perception in Humans

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.

Study Overview

• Status: Completed
• Conditions: Obesity

Detailed Description

1. 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.

2. 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.

• Study Type: Observational
• Enrollment (Actual): 40

Contacts and Locations

Study Locations

• United States
  • Missouri
    • Saint Louis, Missouri, United States, 63110
      • Washington University School of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 50 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

A total of 40 obese subjects will participate in this study. Subjects will be men and women and will include all races and ethnic groups. The two groups (carriers and non-will be matched as closely as possible in age, sex, body mass index (kg/m²) and race distributions.

Description

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

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
rs1761667- AA genotype; 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; subjects who are homozygous of CD36 genotype rs1761667-G allele.
rs1761667-AG genotype; Heterozygous of CD36 gene rs1761667-A genotype.

What is the study measuring?

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.

Collaborators and Investigators

• Sponsor: Washington University School of Medicine
• Collaborators: GlaxoSmithKline

Study record dates

Study Major Dates

• Study Start: May 1, 2010
• Primary Completion (Actual): June 1, 2014
• Study Completion (Actual): June 1, 2014

Study Registration Dates

• First Submitted: May 20, 2010
• First Submitted That Met QC Criteria: May 20, 2010
• First Posted (Estimate): May 21, 2010

Study Record Updates

• Last Update Posted (Actual): July 17, 2018
• Last Update Submitted That Met QC Criteria: June 18, 2018
• Last Verified: June 1, 2018

More Information

Terms related to this study

• Keywords: obesity; orlistat; taste perception
• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: 09-0873

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No