ORIGINAL RESEARCH article
Front. Nutr.
Sec. Nutrition, Psychology and Brain Health
This article is part of the Research TopicEmerging Trends in Functional Food Formulation: From Concept to ConsumersView all articles
A low-calorie rebaudioside D–glucose–sodium sweetener matches sucrose in palatability and neural responses in a functional MRI study of healthy adults
Provisionally accepted
- 1The Center for Evolutionary Cognitive Sciences at the University of Tokyo, Tokyo, Japan
- 2Suntory Beverage & Food Ltd, Minato, Japan
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Introduction: Non-nutritive sweeteners (NNSs) often taste less palatable than glucose-containing sugars, potentially because they differentially engage sweet taste pathways. In this study, we examined a low-calorie rebaudioside D–glucose–sodium (RebD mix) sweetener, formulated on the basis of previous evidence that its components can engage type 1 taste receptors 2 and 3 (T1r2/T1r3) and sodium–glucose cotransporter 1 (SGLT1)–related pathways. We tested whether the RebD mix matches sucrose in palatability and neural responses. Methods: A within-subject fMRI study was performed on 28 healthy adults (mean age 22.36 ± standard deviation [SD] 5.20 years; male = 22: body mass index [BMI] kg/m2= 20.34 ± 2.22 SD). During scanning, participants received three gustatory conditions in randomized order, with tasteless rinses (9 sec) between trials: sucrose (234 mM), RebD mix (29.2 mM sucrose + 194.3 mM glucose + 0.156 mM RebD + 5mM sodium gluconate), and RebD mix without sodium (Na+) (29.2 mM sucrose + 194.3 mM glucose + 0.184mM RebD), which is known to enhance SGLT1 activation. Liking and wanting ratings for gustatory stimuli were obtained at scanning. Imaging analyses focused on the orbitofrontal cortex (OFC), a key region associated with palatability, and OFC-centered functional connectivity, using within-participant contrasts across the three gustatory conditions. Results: Liking and wanting did not differ across the three conditions. OFC response to the RebD mix did not differ from sucrose, whereas the RebD without Na+ condition showed greater OFC–postcentral gyrus connectivity than the other two conditions (psBonferroni-corrected < 0.001). Across participants, OFC–postcentral connectivity in the RebD without Na+ condition was negatively associated with fullness measured at scanning. Conclusion: The RebD mix matched sucrose in subjective palatability and OFC responses, while removal of Na+ altered OFC– postcentral gyrus connectivity linked to satiety. These findings indicate that the RebD mix, a novel low-calorie formulation, may achieve sucrose-comparable palatability.
Keywords: functional MRI, Non-nutritive sweeteners, palatability, Rebaudioside D, Stevia
Received: 05 Sep 2025; Accepted: 05 Dec 2025.
Copyright: © 2025 Nakamura, Takahashi and Ohkuri. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yuko Nakamura
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