Individual Differences in Retronasal Odor Responsiveness: Effects of Aging and Concurrent Taste

Abstract

Introduction Individual differences in taste sensitivity have been considered the primary chemosensory factor in studies of chemical senses/ingestive behavior. Recent findings suggest, however, that retronasal odor perception is equally important in food preference and selection and, furthermore, the presence of a congruent taste can modulate responsiveness to retronasally perceived odors. The primary objective of this study was to measure individual differences in responsiveness to food odors in the presence and absence of a congruent taste. In order to achieve this goal, we experimentally manipulated the way taste and odor stimuli are presented. We hypothesized that when measured independently, variations across subjects in responsiveness to retronasal odors are greater than those of tastes, but that these variations are effectively reduced by the presence of a congruent taste, especially for the older cohort. Methods Two groups of subjects (young vs. old cohorts) were asked to sample two tastants, four food odorants, and the congruent taste-odor pairs, and rate intensities for appropriate categories.Results Results showed that responsiveness to odors varied greatly across individuals compared to that of tastes and further that variations in odor responsiveness were greater for old compared to young cohort. In the presence of a congruent taste, however, the variations in responsiveness to the odors were significantly reduced, in particular for the old cohort. Implication The current data suggest that older individuals and those with low olfactory sensitivity may not recognize the reduced sensitivity when consuming foods.

Factors Contributing to Interindividual Variation in Retronasal Odor Perception from Aroma Glycosides: The Role of Odorant Sensory Detection Threshold, Oral Microbiota, and Hydrolysis in Saliva

“…Olfactory detection thresholds are a known source of variation. Although they are usually reported as a single value (group best estimate threshold), they commonly vary between individuals by 3 orders of magnitude or more and typically 14–23% of individuals are insensitive to a given odor . Other plausible factors that might contribute to interindividual variation in flavor perception from glycosides include variations in the saliva flow rate and buffering capacity and mouth movement and breathing behavior …”

Human Oral Sensitivity to and Taste Modulation by 3-Mercapto-2-Methylpentan-1-ol

“…However, flavor depends more on oral presentation, a key component of which is retronasal olfaction (Delwiche 2004;Shepherd 2006). Since nasal concentration, patterns of sorption on the nasal mucosa, and neural processing can differ between routes of presentation, sensation may also differ (Linforth et al 2002;Bojanowski and Hummel 2012;Scott et al 2014;Flaherty and Lim 2017;Hannum et al 2018;Blankenship et al 2019;Sanganahalli et al 2020). Accordingly, one goal was to measure oral sensitivity to 3 M solutions, including detection thresholds (Experiment 1), recognition thresholds (Experiment 2), and supra-threshold intensity vs. concentration (Experiment 3).…”

Mechanisms of umami taste perception: From molecular level to brain imaging

“…The variability in human umami taste perception is still poorly understood, however a genetic mechanism is possibly behind these variations, with links to the heterodimeric receptor T1R1 and T1R3 (Raliou et al 2009;. Different studies conducted a comprehensive evaluation of single-nucleotide polymorphisms (SNPs) and haplotypes in human TAS1R1 and TAS1R3 genes and revealed several SNPs within the extracellular domain of T1R1 and T1R3 (Chen et al 2009;Flaherty and Lim 2017;Puputti et al 2018;Satoh-Kuriwada et al 2014;Simmons and Estes 2008;Singh, Schuster, and Seo 2010). Raliou et al (2009) found variations in genes T1ASR1 and TAS1R3 in human fungiform papillae and suggested that these receptor variations contributed to the individual differences in glutamate sensitivity in the studied population (European Caucasian) (Raliou et al 2009).…”