The purpose of this study is to investigate the effects of dietary exposure to artificial sweeteners on taste sensitivity, preference and brain response in adolescents using fMRI, psychophysical measures, and questionnaires. 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.
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. Adolescents may be more sensitive to exposure to AFS because of changes in metabolism during this period of development. Physiologic insulin resistance occurs during adolescence (Moran, Jacobs et al. 1999); this change in insulin sensitivity may predispose adolescents to greater impairments in sweet taste intensity by altering the relationship between sweet taste and post-ingestive reward, as suggested by the Davidson and Swithers model (Davidson and Swithers 2004). Therefore, it is imperative that we gain a greater understanding of the physiological consequences of AFS use in adolescents, since alterations in sweet taste perception, metabolism and brain reward that occur in response to AFS exposure may promote weight gain.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
2 packets
equisweet to sucralose
sucralose plus equicaloric (to sucrose) maltodextrin
The John B. Pierce Laboratory
New Haven, Connecticut, United States
Ratings of taste sensitivity
At baseline and after on average 2 weeks, subjects will rate intensity of sucrose, sucralose, mono potassium glutamate, sodium chloride and citric acid using the General Labeled Magnitude Scale (gLMS). It is a vertical line with quasi-logarithmic spaced labels that start at the bottom with 'barely detectable' to 'strongest imaginable' at the top, recoded to 0-100.
Time frame: on average 2 weeks
Insulin resistance and GLP-1
We will draw a blood sample to assess glucose, insulin and GLP-1
Time frame: on average 2 weeks
Ad libitum food intake
Subject is offered milk and cereal and asked to consume as much as they want. The amount consumed is measured in weight and converted to calories.
Time frame: on average 2 weeks
percent signal change of brain response in reward and gustatory areas to taste stimuli
brain response in reward and gustatory areas to sucrose, mono potassium glutamate, sodium chloride and citric acid (in percent signal change).
Time frame: on average 2 weeks
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Enrollment
15