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Our sense of taste arises from the sensory information generated after compounds in the oral cavity and oropharynx activate taste receptor cells situated on taste buds. This produces the perception of sweet, bitter, salty, sour, or umami stimuli, depending on the chemical nature of the tastant. Taste impairments (dysgeusia) are alterations of this normal gustatory functioning that may result in complete taste losses (ageusia), partial reductions (hypogeusia), or over-acuteness of the sense of taste (hypergeusia). Taste impairments are not life-threatening conditions, but they can cause sufficient discomfort and lead to appetite loss and changes in eating habits, with possible effects on health. Determinants of such alterations are multiple and consist of both genetic and environmental factors, including aging, exposure to chemicals, drugs, trauma, high alcohol consumption, cigarette smoking, poor oral health, malnutrition, and viral upper respiratory infections including influenza. Disturbances or loss of smell, taste, and chemesthesis have also emerged as predominant neurological symptoms of infection by the recent Coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus strain 2 (SARS-CoV-2), as well as by previous both endemic and pandemic coronaviruses such as Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and SARS-CoV. This review is focused on the main causes of alteration, reduction, and loss of taste and their potential repercussion on dietary habits and health, with a special focus on the recently developed hypotheses regarding the mechanisms through which SARS-CoV-2 might alter taste perception.

It was shown more than 40 years ago that the ability to perceive the bitterness of the fruit of the Antidesma bunius tree is inversely correlated with the ability to perceive the well-studied bitter tastant phenylthiocarbamide (PTC). To determine if variants of the TAS2R38 gene, which encodes the PTC taste receptor, or variants in any of the other TAS2R bitter or TAS1R sweet receptor genes account for Antidesma taste perception, we recruited an independent subject sample and examined associations between these taste receptor gene haplotypes and Antidesma perception. Consistent with previous findings, almost none of our subjects who reported Antidesma juice as bitter was a PTC "responder" by previous definitions (i.e. a PTC taster). In our study, of the 132 individuals who perceived PTC as bitter, 15 perceived Antidesma as bitter, although these 15 subjects had very weak bitterness perception scores. Examination of TAS2R38 gene haplotypes showed that, of the subjects who perceive Antidesma as bitter, all carried at least one copy of the TAS2R38 AVI (PTC non-taster) haplotype. However, 86 subjects carried at least one AVI haplotype and failed to perceive Antidesma as bitter. No other TAS2R or TAS1R gene variants showed an association with Antidesma bitter, sweet, or sour perception. Our results show that TAS2R38 haplotypes are associated with differential perception of Antidesma berry juice bitterness, and that all those who perceive this bitterness carry at least one AVI haplotype. This indicates that the AVI haplotype is necessary for this perception, but that additional variable factors are involved.

The study of food choice, one of the most complex human traits, requires an integrated approach that takes into account environmental, socio-cultural and biological diversity. We recruited 183 volunteers from four geo-linguistic groups and highly diversified in terms of both genetic background and food habits from whom we collected genotypes and phenotypes tightly linked to taste perception. We confirmed previous genetic associations, in particular with stevioside perception, and noted significant differences in food consumption: in particular, broccoli, mustard and beer consumption scores were significantly higher (Adjusted P = 0.02, Adjusted P < 0.0001 and Adjusted P = 0.01, respectively) in North Europeans, when compared to the other groups. Licorice and Parmesan cheese showed lower consumption and liking scores in the Sri Lankan group (Adjusted P = 0.001 and Adjusted P < 0.001, respectively). We also highlighted how rs860170 (TAS2R16) strongly differentiated populations and was associated to salicin bitterness perception. Identifying genetic variants on chemosensory receptors that vary across populations and show associations with taste perception and food habits represents a step towards a better comprehension of this complex trait, aimed at improving the individual health status. This is the first study that concurrently explores the contribution of genetics, population diversity and cultural aspects in taste perception and food consumption., (Published by Elsevier Ltd.)

Understanding cross-cultural differences in food perception is a key issue of food research in order to understand consumer behaviour in different countries. The objective of this study was to explore potential cultural differences of balsamic vinegar perception between Korean and Italian consumers using the sorted napping method. Nine balsamic vinegars different in terms of ingredients, aging time, and origin were evaluated by Korean (n=50) and Italian (n=49) consumers using sorted napping. Familiarity and food matching were also examined. Descriptive analysis was performed to verify the attitude of the consumers in product description. The results obtained from two groups of consumers in Korea and Italy revealed a higher description attitude of the Italians (higher number of total elicited attributes, of attributes in common with the trained panel, of attributes shared with the vocabulary reported in literature, of significant specific positive product-attribute associations). Italian subjects generated various descriptors associated with the European gastronomic culture (aromatic herbs, fortified wine, dried figs, Indian fig, Parmigiano-Reggiano cheese), whereas Korean consumers used more terms related to the Asian food culture (red ginseng, Chinese medicine, Japanese apricot, teriyaki sauce, persimmon vinegar, balloon flower roots). Moreover, cultural differences of food matching were also observed: the Italians would pair the balsamic vinegars mainly with vegetables, fruits and cheese, while Koreans would combine the balsamic vinegars preferably with bread, vegetables and meat. In conclusion, familiarity resulted the main factors for cross-cultural differentiation., (Copyright © 2016. Published by Elsevier Ltd.)

Objectives: The extent to which variation in taste perception influences food preferences is, to date, controversial. Bitterness in food triggers an innate aversion that is responsible for dietary restriction in children. We investigated the association among genetic variations in bitter receptor TAS2R38 and food choices in healthy children in the Mediterranean area, to develop appropriate tools to evaluate the relation among genetic predisposition, dietary habits, and feeding disorders. The aims of the study were to get a first baseline picture of taste sensitivity in healthy adults and their children and to explore taste sensitivity in a preliminary sample of obese children and in samples affected by functional gastrointestinal diseases., Methods: Individuals (98 children, 87 parents, 120 adults) were recruited from the general population in southern Italy. Bitterness sensitivity was assessed by means of a suprathreshold method with 6-propyl-2-thiouracil. Genomic DNA from saliva was used to genotype individuals for 3 polymorphisms of TAS2R38 receptor, A49P, A262 V, and V296I. Food intake was assessed by a food frequency questionnaire., Results: Children's taste sensation differed from that of adults: we observed a higher frequency of supertasters among children even in the mother-child dyads with the same diplotypes. Among adults, supertaster status was related with proline-alanine-valine (taster allele) homozygous haplotype, whereas supertaster children were mainly heterozygous. Regarding the food choices, we found that a higher percentage of taster children avoided bitter vegetables or greens altogether compared with taster adults. Taster status was also associated with body mass index in boys., Conclusions: Greater sensitivity to 6-propyl-2-thiouracil predicts lower preferences for vegetables in children, showing an appreciable effect of the genetic predisposition on food choices. None of the obese boys was a supertaster.

The current study reports an ethnobotanical field investigation of traditionally gathered and consumed wild greens (Chorta) in one of the five so-called Blue Zones in the world: Ikaria Isle, Greece. Through 31 semi-structured interviews, a total of 56 wild green plants were documented along with their culinary uses, linguistic labels, and locally perceived tastes. Most of the gathered greens were described as bitter and associated with members of Asteraceae and Brassicaceae botanical families (31%), while among the top-quoted wild greens, species belonging to these two plant families accounted for 50% of the wild vegetables, which were consumed mostly cooked. Cross-cultural comparison with foraging in other areas of the central-eastern Mediterranean and the Near East demonstrated a remarkable overlapping of Ikarian greens with Cretan and Sicilian, as well as in the prevalence of bitter-tasting botanical genera. Important differences with other wild greens-related food heritage were found, most notably with the Armenian and Kurdish ones, which do not commonly feature many bitter greens. The proven role of extra-oral bitter taste receptors in the modulation of gastric emptying, glucose absorption and crosstalk with microbiota opens new ways of looking at these differences, in particular with regard to possible health implications. The present study is also an important attempt to preserve and document the bio-cultural gastronomic heritage of Chorta as a quintessential part of the Mediterranean diet. The study recommends that nutritionists, food scientists, and historians, as well as policymakers and practitioners, pay the required attention to traditional rural dietary systems as models of sustainable health. [ABSTRACT FROM AUTHOR]