The Effect of Artificial Sweeteners (AFS) on Sweetness Sensitivity, Preference and Brain Response in Adults

Study Overview
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Brief Summary
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The purpose of this study is to investigate the effects of dietary exposure to artificial sweeteners on taste sensitivity, preference and brain response in adults. The investigators hypothesize that dietary exposure to artificial sweeteners (sucralose) will decrease sensitivity to taste, shift preference of sweet and savory taste to a higher dose, and reduce brain response in amygdala to sweet taste compared to sucrose.

Detailed Description
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We aim to identify neural factors that contribute to taste intensity perception in humans and to determine environmental mechanisms that contribute to variation in taste sensitivity. Significant controversy surrounds the possibility that consumption of artificial sweeteners (AFS) leads to weight gain. Given that the five FDA approved AFSs are found in thousands of foods (Yang 2010) this marks a clear and significant gap in knowledge. Our preliminary data demonstrate a 3-fold decrease in sweet taste sensitivity following consumption of a beverage sweetened with two packets of Splenda for just 10 days. These data provide strong evidence that repeated exposure to sucralose reduces perception of sweet taste intensity, most likely by down-regulation of the sweet taste receptor. Therefore, it is imperative that we gain a greater understanding of the physiological consequences of AFS, since alterations in sweet taste perception, metabolism and brain reward that occur in response to AFS exposure may promote weight gain.

Official Title
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The Effect of Artificial Sweeteners (AFS) on Sweetness Sensitivity, Preference and Brain Response in Adults

Conditions
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Impairment of Oral Perception, Insulin Resistance

Intervention / Treatment
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* Dietary Supplement: Sucralose
* Dietary Supplement: Sucrose
* Dietary Supplement: Sucralose + maltodextrin
* Dietary Supplement: Sucralose + Sucrose


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy Fluent in English Right handed Exclusion Criteria: History of oral nerve damage, presence of known taste or smell disorder, food allergies or sensitivities (for example nuts, lactose, artificial sweeteners), history of CNS disease, diabetes, history of DSM-IV major psychiatric disorder, including alcohol and substance abuse, chronic use of medication that may affect taste, conditions that may interfere with gustatory or olfactory perception (colds, seasonal allergies, recent smoking history), aberrant stimulus ratings, contra-indication for fMRI, uncomfortable swallowing in supine position, discomfort or anxiety associated with insertion an intravenous catheter, regular artificial sweetener use.

Ages Eligible for Study
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Minimum Age: 23 Years
Maximum Age: 45 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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sucralose<br>Participants will rate sweetness, sourness, saltiness, bitterness and umami intensity of various taste stimuli. Next they will consume a flavored beverage with sucralose. | Dietary Supplement: Sucralose<br>* 2 packets per 12 fl oz<br>|
| Experimental: Sucrose<br>Participants will rate sweetness, sourness, saltiness, bitterness and umami intensity of various taste stimuli. Next they will consume a flavored beverage with sucrose. | Dietary Supplement: Sucrose<br>* equisweet to sucralose<br>|
| Experimental: Sucralose + maltodextrin<br>Participants will rate sweetness, sourness, saltiness, bitterness and umami intensity of various taste stimuli. Next they will consume a flavored beverage with Splenda + maltodextrin . | Dietary Supplement: Sucralose + maltodextrin<br>* sucralose plus equicaloric (to sucrose) maltodextrin<br>|
| Experimental: Sucralose + Sucrose<br>Participants will rate sweetness, sourness, saltiness, bitterness and umami intensity of various taste stimuli. Next they will consume a flavored beverage with Splenda + sucrose. | Dietary Supplement: Sucralose + Sucrose<br>* half the amount of sucralose plus equicaloric sucrose<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ratings of taste sensitivity | general labeled magnitude scale ratings of taste intensity | up to one week after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ad libitum food intake | amount of Mac&Cheese consumed | up to one week after intervention | 
| brain response to taste stimuli | BOLD response as measured by fMRI | up to one week after intervention |