Repeated Exposure to Umami Taste on Taste Perception, Hedonics, and Satiety

Study Overview
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Brief Summary
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The purpose of this study is to determine how repeated dietary exposure to umami taste affects umami taste perception, hedonics, food preferences, and satiety. Healthy adult subjects will consume a low glutamate vegetable broth daily for one month, where the experimental group's broth is supplemented with the umami-rich stimuli of monosodium glutamate (MSG) and the control group's low glutamate broth is matched for sodium (NaCl). The investigators hypothesize that repeated dietary exposure to umami taste will: diminish umami suprathreshold intensity perception and hinder the ability to discriminate varying MSG concentrations decrease liking of umami-rich foods and shift preferences upwards towards more intense umami stimuli decrease satiation and decrease the satiating effect of a test meal

Official Title
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Does Repeated Dietary Exposure to Umami Taste Affect Umami Perception, Hedonics, or Satiety? A Randomized Controlled Study

Conditions
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Umami Taste Perception

Intervention / Treatment
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* Other: Supplementation of diet with MSG
* Other: No supplementation of diet with MSG


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Have normal sense of taste and smell (self-report) Likes soups or broths (self-report) Able to report to study site daily (self-report) Exclusion Criteria: Restrained eater (score > 12 on restrained eating subscale from Three Factor Eating Questionnaire) BMI < 18 or > 25 kg/m2 (self-report) Vegan (self-report) Hypertensive or on low-sodium diet (self-report) Allergic or sensitive to MSG (self-report)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Increased exposure to MSG<br>Subjects consume vegetable broth daily containing MSG | Other: Supplementation of diet with MSG<br>* Subjects eat normal diet and consume 8 ounces of vegetable broth with added MSG one time per day for 1 month<br>|
| Sham Comparator: No change in exposure to MSG<br>Subjects consume low glutamate vegetable broth daily, sodium-matched to the broth of the experimental group with NaCl | Other: No supplementation of diet with MSG<br>* Subjects eat normal diet and consume 8 ounces of low glutamate vegetable broth without MSG (sodium-matched with NaCl) one time per day for 1 month<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in umami taste intensity perception | Subjects rate the umami intensity of aqueous solutions and foods on the general Labeled Magnitude Scale before and after a month-long dietary supplementation to determine how perception changes with repeated exposure to umami taste | 1 month (at baseline and post intervention) | 
| Change in umami taste discrimination | Subjects rank solutions of varying umami intensity before and after a month-long dietary supplementation to determine how perception changes with repeated exposure to umami taste | 1 month (at baseline and post intervention) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in umami liking and preference | Subjects rate liking and preference in a variety of umami-rich foods before and after a month-long dietary supplementation to determine how liking and preference of umami-rich foods changes with repeated exposure to umami taste | 1 month (at baseline and post intervention) | 
| Change in liking and wanting of high protein foods | Subjects complete the Leeds Food Preference Questionnaire before and after a month-long dietary supplementation to determine how explicit liking and implicit wanting of high-protein foods changes with repeated exposure to umami taste | 1 month (at baseline and post intervention) | 
| Change in satiation | Subjects consume a test meal and the amount of food eaten is measured before and after a month-long dietary supplementation to determine how satiation from a test meal differs after repeated exposure to umami taste | 1 month (at baseline and post intervention) | 
| Change in satiety | Subjects consume a test meal and rate appetite sensations on a visual analog scale throughout the test meal before and after a month-long dietary supplementation. A satiety quotient will be derived from these values with the formula: Satiety Quotient = (rating pre-eating episode-rating post-eating episode) / (intake of eating episode) to determine how satiety changes with repeated exposure to umami taste | 1 month (at baseline and post intervention) |