@article {10582, title = {Factors Influencing the Phenotypic Characterization of the Oral Marker, PROP.}, journal = {Nutrients}, volume = {9}, year = {2017}, month = {2017 Nov 23}, abstract = {

In the last several decades, the genetic ability to taste the bitter compound, 6--propyltiouracil (PROP) has attracted considerable attention as a model for understanding individual differences in taste perception, and as an oral marker for food preferences and eating behavior that ultimately impacts nutritional status and health. However, some studies do not support this role. This review describes common factors that can influence the characterization of this phenotype including: (1) changes in taste sensitivity with increasing age; (2) gender differences in taste perception; and (3) effects of smoking and obesity. We suggest that attention to these factors during PROP screening could strengthen the associations between this phenotype and a variety of health outcomes ranging from variation in body composition to oral health and cancer risk.

}, keywords = {Food Preferences, Genetic Variation, Humans, Propylthiouracil, Taste Perception, Taste Threshold}, issn = {2072-6643}, doi = {10.3390/nu9121275}, author = {Tepper, Beverly J and Melis, Melania and Koelliker, Yvonne and Gasparini, Paolo and Ahijevych, Karen L and Tomassini Barbarossa, Iole} } @article {8297, title = {Understanding the role of personality and alexithymia in food preferences and PROP taste perception.}, journal = {Physiol Behav}, volume = {157}, year = {2016}, month = {2016 Apr 1}, pages = {72-8}, abstract = {

Taste perception and food preferences are influenced by a variety of factors, including personality characteristics. The aims of this study were to examine the role of personality characteristics, such as alexithymia (a personality construct characterized by inability to identify, describe, and work with one{\textquoteright}s own feelings), in: 1) taste responses to the bitter genetic taste-marker PROP and 2) food liking. We studied 649 healthy subjects residing in six genetically-isolated villages of Northeast Italy. Data on PROP taste responsiveness, food liking, personality characteristics and TAS2R28 genotypes were collected. Results showed that PROP non-tasters had higher alexithymia scores than PROP tasters. Moreover, the presence of alexithymia in heterozygous individuals for the rs1726886 polymorphism of the TAS2R38 gene was associated with a reduction in the perceived intensity of PROP. Finally, higher alexithymia scores were associated with liking of alcohol, sweets and fats/meats whereas lower alexithymia scores were related to liking of vegetables, condiments and strong cheeses, Measures of temperament, character, anxiety and depression were also related to food liking. Our findings suggest that: 1) alexithymia, in addition to the TAS2R38 polymorphism, may play a role in responsiveness to the aversive and bitter taste of PROP; and 2) alexithymia, in combination with other personality traits, may provide important insights for better understanding food liking.

}, issn = {1873-507X}, doi = {10.1016/j.physbeh.2016.01.022}, author = {Robino, Antonietta and Mezzavilla, Massimo and Pirastu, Nicola and La Bianca, Martina and Gasparini, Paolo and Carlino, Davide and Tepper, Beverly J} } @article {3507, title = {A population-based approach to study the impact of PROP perception on food liking in populations along the Silk Road.}, journal = {PLoS One}, volume = {9}, year = {2014}, month = {2014}, pages = {e91716}, abstract = {

Taste is one of the main factors determining food choices. Differences in PROP bitter taste perception have been implicated in individual differences in food preferences and selection. The present study examined associations between, PROP phenotypes, self-reported food liking and TAS2R38 polymorphisms, the major gene implicated in PROP bitterness, in six different populations of the Caucasus and Central Asia, located along the ancient Silk Road. Differences in the distribution of PROP phenotypes across populations were detected, with a higher frequency of super tasters in Tajikistan (31.3\%) and Armenia (39.0\%) and a higher frequency of non tasters in Georgia (50.9\%). While no relationships were observed between PROP phenotypes and food liking using standard statistical tests, we used an approach based on comparison of distance matrices derived from these data. The first matrix compared the food liking ratings of each population to all others pairwise using the Kruskal-Wallis test (at p<0.00063), and the second one compared the distribution of PROP phenotypes across all populations in a similar manner calculating the chi-square statistic as a distance measure. A strong correlation between the two matrices was found (Mantel test: r = 0.67, p-value = 0.03), suggesting that the pattern of food liking across populations was closely related to the distribution of PROP phenotypes. This same relationship was not observed when TAS2R38 genotypes were substituted for PROP phenotypes in this analysis. Our data suggest that a population-based approach utilizing distance matrices is a useful technique for detecting PROP-related differences in food liking and can be applied to other taste phenotypes.

}, keywords = {Armenia, Azerbaijan, Food, Genetic Association Studies, Genotype, Haplotypes, Humans, Polymorphism, Single Nucleotide, Propylthiouracil, Receptors, G-Protein-Coupled, Tajikistan, Taste, Taste Perception, Uzbekistan}, issn = {1932-6203}, doi = {10.1371/journal.pone.0091716}, author = {Robino, Antonietta and Mezzavilla, Massimo and Pirastu, Nicola and Dognini, Maddalena and Tepper, Beverly J and Gasparini, Paolo} } @article {1960, title = {Genetics of food preferences: a first view from silk road populations.}, journal = {J Food Sci}, volume = {77}, year = {2012}, month = {2012 Dec}, pages = {S413-8}, abstract = {

Food preferences are the main factor driving food intake and choice. There are good reasons to suspect some genetic influence on food acceptance, not least because genetic factors are implicated in a number of factors that are likely to be related to food choice. In addition, some food dislikes show themselves early in life, before there is any evidence for aversive experiences. Although taste has been widely studied in regards of pure tastes such as bitter or sweet perception, the relationship between taste-related genes and food preferences has seldom been explored. In this work we investigated relationship of 37 taste-related genes with food preferences. The study was carried out during a scientific expedition through Caucasus and Central Asia (Silk Road) analyzing more than 400 samples from 5 different countries. A food preference questionnaire was administered to each participant and a DNA sample was obtained. Other information, such as age, sex, life style and anthropometrical measures, were also collected. We found significant associations with variants of: (1) TAS1R2 [Correction added after initial online publication on 27 Aug 2012. TAS1R3 was changed to TAS1R2.] gene and liking of Vodka (P= 1.6 {\texttimes} 10(-3)), white wine (P= 4.0 {\texttimes} 10(-4)) and lamb meat (P= 1.6 {\texttimes} 10(-3)); (2) PCLB2 gene and preference for Hot Tea (P= 8.0 {\texttimes} 10(-4)); (3) TPRV1 gene and beet liking (P= 3.8 {\texttimes} 10(-5)); and (4) ITPR3 gene and liking of both lamb meat (5.8 {\texttimes} 10(-4)) and sheep cheese (8.9{\texttimes}10(-4)). These findings give a new insight on a better understanding, of genetic factors influencing food preferences which is critical to the development of effective dietary interventions, especially for people that may be genetically not predisposed for liking specific nutrients.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Azerbaijan, Child, Choice Behavior, Cohort Studies, Female, Food Habits, Food Preferences, Gene Frequency, Genotype, Georgia, Humans, Kazakhstan, Linear Models, Male, Middle Aged, Polymorphism, Single Nucleotide, Quantitative Trait Loci, Questionnaires, Tajikistan, Taste, Uzbekistan, Young Adult}, issn = {1750-3841}, doi = {10.1111/j.1750-3841.2012.02852.x}, author = {Pirastu, Nicola and Robino, Antonietta and Lanzara, Carmela and Athanasakis, Emmanouil and Esposito, Laura and Tepper, Beverly J and Gasparini, Paolo} } @article {1622, title = {Individual differences in prefrontal cortex activity during perception of bitter taste using fNIRS methodology.}, journal = {Chem Senses}, volume = {35}, year = {2010}, month = {2010 Nov}, pages = {801-12}, abstract = {

Although bitter taste has a crucial role in nutrition by preventing the ingestion of toxic foods, there are few studies on bitter taste neuroimaging. To identify cortical areas involved in bitter taste perception and to determine if individual differences in taste sensitivity to 6-n-propylthiouracil (PROP) are represented in the brain by different cortical activation patterns, we examined 48 healthy volunteers using functional near-infrared spectroscopy. Participants rated the perceived intensity of filter paper disks impregnated with PROP and NaCl during the imaging procedure and were then classified as PROP tasters and nontasters. We monitored cortical activity in both the anterior and posterior regions of the dorsolateral prefrontal cortex (DLPFC) and in the ventrolateral prefrontal cortex (VLPFC). No activity was detected in the anterior DLPFC in any of the participants. However, during the administration of PROP, significant cortical activation was detected in the more posterior regions of the left DLPFC and in the left and right VLPFC but only in PROP tasters. PROP nontasters showed no cortical activity in these areas. These data suggest that the prefrontal cortex is involved in the conscious perception of the bitter taste of PROP and that the pattern of activity is consistent with individual differences in the ability to taste this compound. Thus, the PROP phenotype is associated with fundamental differences in cortical taste processing.

}, keywords = {Adult, Eating, Female, Food Preferences, Humans, Individuality, Male, Perception, Phenotype, Prefrontal Cortex, Propylthiouracil, Sodium Chloride, Spectroscopy, Near-Infrared, Taste, Taste Threshold, Young Adult}, issn = {1464-3553}, doi = {10.1093/chemse/bjq080}, author = {Bembich, Stefano and Lanzara, Carmela and Clarici, Andrea and Demarini, Sergio and Tepper, Beverly J and Gasparini, Paolo and Grasso, Domenico L} }