Browsing by Author "Nelson I"

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    The effect of a 14-day Gymnema sylvestre intervention to reduce sugar intake in people self-identifying with a sweet tooth
    (Elsevier Ltd, 2025-01-28) Hsiao WH; Kruger R; Diako C; Nelson I; Stice E; Ali A
    Gymnema sylvestre (GS) contains gymnemic acids which can reversibly suppress sweet taste responses. This randomised crossover study aimed to investigate whether supplemental GS use can reduce sugar cravings, sweet food desire and consumption among adults that identify as high sweet food consumers (having a ‘sweet tooth’). Participants were told three different mints were trialled to avoid bias. On day zero, 32 healthy participants underwent baseline sensory testing for sweet taste perception using the placebo mint (PLAC). Participants were then randomised into the two intervention groups. On day 15 and 30, participants underwent further sensory testing using the GS mints, before embarking on each 14-day intervention using the GS mints, using either a systematic (at 3 specified times/day; SYS) or ad libitum (up to 6 mints/day at times of their choosing; AD-LIB) regimen, as assigned. On day 30, participants swapped over to the other intervention (using the other regimen), completing final data collection in day 45. At all visits participants completed questionnaires (food frequency questionnaire, beverage questionnaire and cravings questionnaire), anthropometric measures, and sensory testing. Sensory testing was not required for day 45. The AD-LIB condition reduced daily sugar-sweetened beverages (SSB) intake by 42% relative to PLAC (p = 0.015) and reduced overall sugar cravings by 28% relative to PLAC (p = 0.045). Both AD-LIB and SYS reduced pleasantness ratings (p < 0.005) and desire (p = 0.005) for more chocolate. Using GS with an ad libitum regimen reduced sugar cravings and changed sweet food desire and consumption in people identifying as having a sweet tooth.
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    The Effect of Gymnema Sylvestre on Motivation to Consume Sweet Foods—A Qualitative Investigation
    (MDPI (Basel, Switzerland), 2025-09-01) Nelson I; Kruger R; Hsiao D; Stice E; Ali A; Min K-J
    Background/Objectives: Excessive intake of sugar-sweetened food (SSF) increases obesity risk. Various psychological, physiological, and environmental factors may drive high consumption of SSF. Due to blocking sweet tastes, the herb Gymnema sylvestre (GS) has been shown to reduce SSF consumption, but its impact on motivation to eat SSF is unknown. This research aimed to qualitatively investigate adults’ perceptions regarding effects of GS on their motivation to eat SSF when administered systematically (three times/day in-between meals, i.e., GS-SYS treatment) or ad libitum (up to six times/day at participants’ discretion, i.e., GS-ADLIB) over 14 days, compared to placebo (taste-matched mint; PLAC-SYS). Methods: This study represents the qualitative investigation of a placebo-controlled randomised cross-over trial, conducted as three 14-day phases. The qualitative investigation included interviews at baseline and three post-testing phases. Seven participants (mean age 34.7 ± 13.8 years; two males, five females) agreed to participate. Twenty-eight interviews (across phases) were thematically analysed using NVivo software, identifying themes and highlighting changes in motivation to eat SSFs across the study. Results: The GS-SYS and GS-ADLIB treatments made SSFs unpleasant to eat and increased mindful eating, subsequently increasing motivation to avoid SSFs. External factors could increase or decrease motivation, depending on individual circumstances. Participants preferred GS-SYS and GS-ADLIB over PLAC-SYS, feeling it was more effective at changing behaviours related to SSF intake. Self-control over SSF intake changed during the study, mostly due to external factors, and in part GS-ADLIB. Conclusions: Participants found both GS administrations successful as motivation to avoid SSF; GS-ADLIB was considered most effective.