<i>TAS2R38 </i>Genotypes and Phenylthiocarbamide Bitter Taste Perception in a Population of Young Adults

Abstract

Background/Aims:TAS2R38 belongs to the TAS2R bitter taste receptor gene family and polymorphisms are associated with differences in bitter taste perception of phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP). The objectives were to test whether the genotype-phenotype relationship varies between ethnocultural groups and whether a filter paper method can predict TAS2R38 genotype. Methods: Subjects (n = 911) aged 20–29 rated the intensity of a PTC-containing filter paper on a scale of 1–9, from ‘not at all bitter’ to ‘extremely bitter’. The TAS2R38 A49P polymorphism was detected by real-time PCR. Results: The overall frequency of the 49A variant was 0.47 and the AA, AP, and PP genotype distribution was 0.24, 0.45 and 0.31, respectively. Those with AA, AP, or PP genotypes had mean bitterness rating scores of 2.3, 4.9, and 5.9, respectively. The 49A variant frequency was significantly lower among Asians (28%) as compared to Caucasians (55%), South Asians (60%) or others (56%) (p < 0.0001). The genotype-phenotype relationship was similar across ethnocultural groups, however, a stronger genotype-phenotype association was observed among women as compared to men. Conclusion: Our findings show that a simple PTC filter paper tasting method strongly predicts TAS2R38 genotype, and that the genotype-phenotype association is similar among ethnocultural groups.

Genotyping Analysis of Bitter-Taste Receptor Genes <i>TAS2R38</i> and <i>TAS2R46</i> in Japanese Patients with Gastrointestinal Cancers

“…Note that the genotype frequencies in Caucasians were 32-34%, 44-49% and 19-22% for the corresponding frequencies with the increased AVI allele frequency as compared to Asians (35,36).…”

Influences of weight, age, gender, genetics, diseases, and ethnicity on bitterness perception: a narrative review of current methodological aspects

“…The selected studies indicate that receptors of and sensitivity to bitter taste are reduced along life, resulting in a low tolerance threshold among children [48,43,46]. Regarding gender, three articles reported that women are more sensitive to bitter taste also during pregnancy [22,23,43], and one did not find differences between genders regarding the number of gustatory papillae [50].…”

“…2009 [48] Differences between palates appear to be mainly due to hormonal differences rather than to genetic identity Duffy et al…”

“…In addition to the interaction between genotype and environment, a complex association between hormones and chemoreceptor functions has been suggested to exist in women [46]. Padiglia et al [47] stated that differences in palate between genders are specifically due to hormonal influences on the salivary components [47,48]. Furthermore, both men and women express the TAS2R38 gene, thus having the same amount of bitterness receptors.…”

“…Furthermore, both men and women express the TAS2R38 gene, thus having the same amount of bitterness receptors. Therefore, differences between palates appear to be mainly due to hormonal differences rather than to genetic identity [47,48]. Bitterness perception is also affected by pregnancy, when the palate becomes more sensitive.…”