An empirical evaluation of supra-threshold sensitivity measures for decremental and incremental stimulus intensity: Data from gustatory and olfactory performance

Taste sensitivities mediate differential snack choices across BMI groups: a study with New Zealand young male individuals

OBJECTIVE

This study aimed to: 1) test for the link between snack choices and BMI using a novel sensory-based classification method; and 2) elucidate the role of gustatory sensitivity in orienting snack choices.

METHODS

The study employed a dual approach involving sensory and nutritional assessments. Ninety-eight European male individuals were tested for gustatory sensitivities to sweetness, saltiness, umami, and lipid perception. Participant food intake was measured over 4 days. A separate cohort of 327 participants categorized the recorded snacks based on taste patterns, enabling profiling of snack choices across body-weight groups.

RESULTS

Results showed clear differentiations in snack choices across the BMI groups: Individuals with a higher BMI consumed more "Sweet" and "Sweet+Fat" snacks and less "Savory" snacks compared with the lower-BMI group (p < 0.05). Mediation analyses confirmed a significant effect of gustatory sensitivity, showing that the greater choice for "Sweet" and "Sweet+Fat" snacks among those with a higher BMI was mediated by sensitivities to sweetness and lipid perception (p = 0.008-0.044).

CONCLUSIONS

Our study revealed that gustatory sensitivity can mediate the relationship between BMI and energy consumption from different snacks. These findings highlight the significance of taste perception in shaping snack choice, suggesting potential strategies for interventions aimed at addressing gustatory sensitivity to promote healthier dietary preferences.

A signal detection reminder methodology to evaluate effects of odor-taste-taste interactions to enhance the perceived saltiness

Currently, numerous attempts are made to increase the perceived saltiness of food without adding more NaCl. In the present study, a method based on a reminder design and signal detection theory was used to evaluate the effects of cheddar cheese odor, meat odor, and monosodium glutamate (MSG) on the perceived saltiness and preference of three intensities of NaCl through the d' and R-Index. A solution of 2 g/L NaCl combined with odorless air was the blind reference product, which was also tested as one of the test products. The reference sample was compared to the target samples. A total of twelve right-handed subjects (19-40 years; body mass index BMI 21-32; 7 females and 5 males) performed sensory difference tasks across six days. Cheddar cheese odor was more effective in increasing the perceived saltiness and preference of NaCl solutions than meat odor. When MSG was added to the NaCl solutions, the perceived saltiness and preference were increased. Overall, the signal detection reminder method could provide a comprehensive psychophysical framework to measure saltiness perception and preference of odor-taste-taste interactions using d' (a distance measure) and R-index (an area measure).

Taste but not smell sensitivities are linked to dietary macronutrient composition

Macronutrient intake and composition of diets (i.e., carbohydrate, protein, and fat) can vary substantially across individuals. Chemosensory functions are hypothesised to play a key role in modulating nutrient choices and intake. The present study tests links between individual gustatory or olfactory supra-threshold sensitivities and dietary macronutrient intake. A total of 98 European males (N = 81 for final analyses; age: 20-40 yo; BMI: 18.9-48.1 kg∙m^-2) were tested for supra-threshold sensitivities (d') to 3-gustatory (i.e., Sucrose, MSG, Dairy fat) and 3-olfactory stimuli (i.e., Vanillin, Methional, Maltol/Furaneol), followed by a 4-day weighed Food Record to give measures of macronutrient intake (kJ) and composition (%). With multivariate analyses (i.e., K-mean clustering, PCA, and Hierarchical Regression), gustatory and olfactory d' were compared across groups of individuals with distinct macronutrient composition or intake. Significant differences in gustatory d' were found across the clusters based on macronutrient composition (p < 0.05), but not for clusters based on intake. Hierarchical regressions suggested that gustatory d' played a significant role in predicting dietary carbohydrate composition and intake, with one-unit d' increase predicting reduction of 3%-4.66% (R² = 0.21, F_(5,75) = 5.38, p = 0.001). Moreover, every one-unit increase in d' to MSG increased protein composition by 3.45% (R² = 0.10, F_(5,75) = 2.83, p = 0.022) and intake by 392 kJ (R² = 0.08, F_(5,75) = 2.41, p = 0.044). By contrast, olfactory d' showed little association to macronutrient composition or intake (p > 0.05). Overall, we present intriguing new evidence that gustatory, but not olfactory, sensitivities are linked to dietary macronutrient composition, with relatively little effect on actual intake. These findings highlight possible action of a sensory-mediated mechanism guiding food choices.

Olfactory and Gustatory Supra-Threshold Sensitivities Are Linked to Ad Libitum Snack Choice

Snacking is a common eating habit in the modern food environment. Individual snack choices vary substantially, with sweet versus savoury snacks linked to differential health outcomes. The role of olfactory and gustatory sensitivities in snack choices and consumption is yet to be tested. A total of 70 Caucasian young males (age: 21−39 years; BMI: 20.5−40.5 kg∙m−2) were tested for their supra-threshold sensitivities to sweet and savoury associated odours and tastants (vanillin, methional; sucrose, NaCl). The participants also attended an ad libitum task in which their intakes of sweet and savoury snacks were recorded and analysed. Univariate and multivariate analyses were used to test for relationships between odour/taste sensitivities and sweet versus savoury snack intake. Results indicated that individual sensitivities to sweet-associated stimuli (e.g., vanillin, sucrose) were negatively linked with intake of the congruent (e.g., sweet) snacks and positively linked with incongruent (e.g., savoury) snacks (p < 0.05). These differences were reflected by energy intake rather than consumption weight (p > 0.05). This study outlines the fundamental roles of olfactory and gustatory sensitivities in snack choices and offers novel insights into inter-individual variability in snack consumption.