Normal taste acuity and preference in female adolescents with impaired 6-n-propylthiouracil sensitivity.
TL;DR: This is the first study to demonstrate that 6-n-propylthiouracil nontasters have taste sensitivity for the four basic tastes similar to that in 6- n-Propylthaviouracil tasters, at least in female adolescents, as measured by the gustatory test using a filter-paper disc method.
Abstract: This study was conducted to determine the relationship between 6-n-propylthiouracil sensitivity and taste characteristics in female students at Nara Women's University. Participants (n=135) were screened for 6-npropylthiouracil sensitivity using a taste test with 0.56 mM 6-n-propylthiouracil solution, and the sensitivity was confirmed by an assay for the bitter-taste receptor gene, TAS2R38. Based on the screening results, 33 6-npropylthiouracil tasters and 21 non-tasters were enrolled. The basic characteristics that are thought to influence taste acuity, including body mass index, saliva volume and serum micronutrient concentrations (iron, zinc and copper), were similar between the two groups. In an analysis using a filter-paper disc method, there were no differences in the acuity for four basic tastes (sweet, salty, sour and bitter) between 6-n-propylthiouracil tasters and non-tasters. In addition, the taste preference for the four basic tastes as measured by a visual analogue scale was also comparable between the two groups. This is the first study to demonstrate that 6-n-propylthiouracil nontasters have taste sensitivity for the four basic tastes similar to that in 6-n-propylthiouracil tasters, at least in female adolescents, as measured by the gustatory test using a filter-paper disc method.
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TL;DR: These are the first data showing an association between sweet taste and saliva proteome, and some differences were sex-dependent, with higher levels of α-amylase and CA-VI in low-sensitivity individuals and higher levels in sensitive ones for both sexes.
Abstract: Sweet taste plays a critical role in determining food preferences and choices. Similar to what happens for other oral sensations, individuals differ in their sensitivity for sweet taste and these inter-individual differences may be responsible for variations in food acceptance. Despite evidence that saliva plays a role in taste perception, this fluid has been mainly studied in the context of bitterness or astringency. We investigated the possible relationship between sweet taste sensitivity and salivary composition in subjects with different sucrose detection thresholds. Saliva collected from 159 young adults was evaluated for pH, total protein concentration and glucose. One- and bi-dimensional electrophoresis (2-DE) were performed and protein profiles compared between sweet sensitivity groups, with proteins that were differently expressed being identified by MALDI-FTICR-MS. Moreover, Western blotting was performed for salivary carbonic anhydrase VI (CA-VI) and cystatins and salivary amylase enzymatic activity was assessed in order to compare groups. Females with low sensitivity to sweet taste had higher salivary concentrations of glucose compared to those with sensitivity. For protein profiles, some differences were sex-dependent, with higher levels of α-amylase and CA-VI in low-sensitivity individuals and higher levels of cystatins in sensitive ones for both sexes. Body mass index was not observed to affect the association between salivary proteome and taste sensitivity. To our knowledge, these are the first data showing an association between sweet taste and saliva proteome.
28 citations
Cites background from "Normal taste acuity and preference ..."
...However, such a relationship is questionable [13] and only a weak link between PROP taste sensitivity and sweet perception has been observed [14]....
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TL;DR: Subjective assessment of taste differs according to food composition and nationality, and it is important to consider taste preferences according to nationality when promoting oral nutritional support.
1 citations
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TL;DR: Saliva protects the taste receptor from damage brought about by dryness and bacterial infection, and from disuse atrophy via a decrease in transport of taste stimuli to the receptor sites, which is a long-term effect of saliva that may be related to taste disorders.
Abstract: Saliva is the principal fluid component of the external environment of the taste receptor cells and, as such, could play a role in taste sensitivity. Its main role includes transport of taste substances to and protection of the taste receptor. In the initial process of taste perception, saliva acts as a solvent for taste substances; salivary water dissolves taste substances, and the latter diffuse to the taste receptor sites. During this process, some salivary constituents chemically interact with taste substances. For example, salivary buffers (e.g., bicarbonate ions) decrease the concentration of free hydrogen ions (sour taste), and there are some salivary proteins which may bind with bitter taste substances. Another effect of saliva on taste transduction is that some salivary constituents can continuously stimulate the taste receptor, resulting in an alteration of taste sensitivity. For example, the taste detection threshold for NaCl is slightly above the salivary sodium concentrations with which the taste receptor is continuously stimulated. In contrast, saliva protects the taste receptor from damage brought about by dryness and bacterial infection, and from disuse atrophy via a decrease in transport of taste stimuli to the receptor sites. This is a long-term effect of saliva that may be related to taste disorders. These various effects of saliva on the taste perception differ depending on the anatomical relationship between the taste buds and oral openings of the ducts of the salivary glands. Many taste buds are localized in the trenches of the foliate and circumvallate papillae, where the lingual minor salivary glands (von Ebner's glands) secrete saliva. Taste buds situated at the surface of the anterior part of the tongue and soft palate are bathed with the mixed saliva secreted mainly by the three major salivary glands.
273 citations
"Normal taste acuity and preference ..." refers background in this paper
...Tasters Non-tasters p value Reference values Number 33 21 Age (year) 21 (19-24) 20 (18-22) <0....
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TL;DR: The hypothesis that fat perception and preference can be linked to genetic and anatomical differences between individuals is supported.
Abstract: Individuals who are sensitive to the bitter compound 6-n-propylthiouracil (PROP) are also more sensitive to selected bitter and sweet substances, to sharp foods and to the trigeminal irritant capsaicin. PROP tasters have a greater density of fungiform papillae, and it is speculated that they also have more trigeminal innervation. Since oral texture perception is also mediated, in part, by trigeminal fibers, it has been proposed that individual differences in fat perception might also be linked to PROP taster status and taste bud density. This work tests the hypothesis that individuals who are PROP tasters: (i) have a higher density of fungiform papillae; (ii) are more sensitive to capsaicin; and (iii) have increased ability to discriminate differences in fat content in salad dressing. Hedonic ratings for the salad dressing were also collected and related to the perceptual judgments. Individual subjects were classified as PROP nontasters, medium tasters or supertasters (n = 25/group) by comparing their psychophysical function for PROP to that of NaCl. Papillae densities (papillae/cm2) were significantly different among the three taster groups (p < 0.0001), and were highest among the supertasters. Both medium tasters and supertasters perceived more oral burn from capsaicin than did nontasters at concentrations of 50, 70 and 100 ppm (p < 0.0001). Medium tasters and supertasters could also discriminate differences in fat content between 40% fat and 10% fat salad dressings (p < 0.005), but the nontasters could not. Although medium and supertasters showed no preference for either dressing, the nontasters preferred the 40% fat sample. The reasons for these latter findings are unclear at present. These data support the hypothesis that fat perception and preference can be linked to genetic and anatomical differences between individuals.
186 citations
Additional excerpts
...Tasters (n=33) Non-tasters (n=21) p value A) Tube number Sweet 6 (1-10) 8 (2-10) 0....
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TL;DR: It is suggested that genetic variation in taste, measured by multiple phenotypes or TAS2R38 genotype, can explain differences in overall consumption of vegetables, and this was not restricted to vegetables that are predominantly bitter.
Abstract: Taste and oral sensations vary in humans. Some of this variation has a genetic basis, and two commonly measured phenotypes are the bitterness of propylthiouracil (PROP) and the number of fungiform papillae on the anterior tongue. While the genetic control of fungiform papilla is unclear, PROP bitterness associates with allelic variation in the taste receptor gene, TAS2R38. The two common alleles are AVI and PAV (proline, alanine, valine, and isoleucine); AVI/AVI homozygotes taste PROP as less bitter than heterozygous or homozygous PAV carriers. In this laboratory-based study, we determined whether taste of a bitter probe (quinine) and vegetable intake varied by taste phenotypes and TAS2R38 genotype in healthy adults (mean age=26 years). Vegetable intake was assessed via two validated, complementary methods: food records (Food Pyramid servings standardized to energy intake) and food frequency questionnaire (general intake question and composite vegetable groups). Quinine bitterness varied with phenotypes but not TAS2R38; quinine was more bitter to those who tasted PROP as more bitter or had more papillae. Nontasters by phenotype or genotype reported greater consumption of vegetables, regardless of type (i.e., the effect generalized to all vegetables and was not restricted to those typically thought of as being bitter). Furthermore, nontasters with more papillae reported greater vegetable consumption than nontasters with fewer papillae, suggesting that when bitterness does not predominate, more papillae enhance vegetable liking. These findings suggest that genetic variation in taste, measured by multiple phenotypes or TAS2R38 genotype, can explain differences in overall consumption of vegetables, and this was not restricted to vegetables that are predominantly bitter.
172 citations
TL;DR: These data imply that the change in PROP bitter sensitivity which occurs over the lifespan (from bitter sensitive to less so) is more common in people with a particular haplotype combination, i.e., AVI/PAV heterozygotes.
Abstract: The purpose of this study was to investigate the effect of TAS2R38 haplotypes and age on human bitter taste perception. Children (3 to 10 yrs), adolescents (11 to 19 yrs) and adults (mostly mothers, 20 to 55 yrs (N = 980) were measured for bitter taste thresholds for 6-n-propylthiouracil (PROP) and genotyped for three polymorphisms of the AS2R38 gene (A49P, V262A, I296V). Subjects were grouped by haplotype and age, as well as sex and race/ethnicity, and compared for PROP thresholds. Subjects with the same haplotype were similar in bitter threshold regardless of race/ethnicity (all ages) or sex (children and adolescents; all p-values > 0.05) but age was a modifier of the genotype-phenotype relationship. Specifically, AVI/PAV heterozygous children could perceive a bitter taste at lower PROP concentrations than could heterozygous adults, with the thresholds of heterozygous adolescents being intermediate (p 0.05) perhaps because there is less variation in taste perception among these homozygotes. These data imply that the change in PROP bitter sensitivity which occurs over the lifespan (from bitter sensitive to less so) is more common in people with a particular haplotype combination, i.e., AVI/PAV heterozygotes.
168 citations
"Normal taste acuity and preference ..." refers background in this paper
...Tasters Non-tasters p value Reference values Number 33 21 Age (year) 21 (19-24) 20 (18-22) <0....
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TL;DR: The results suggest that the sweet liker/disliker distinction is robust and valid, and that sensitivity to PROP may influence preference for sweet by altering the quality of sweet.
148 citations