Variation in the bitter-taste receptor gene TAS2R38, and adiposity in a genetically isolated population in Southern Italy.
OBJECTIVE
Variation in the bitter-taste receptor gene, TAS2R38 confers the ability to taste 6-n-propylthiouracil (PROP). The objective of this study was to relate TAS2R38 haplotypes and PROP-tasting phenotypes to adiposity in a genetically isolated population. We hypothesized that the nontaster phenotype would be associated with higher BMI and waist circumference (WC) in females, and that dietary restraint would mediate this relationship.


METHODS
Participants were 540 healthy inhabitants of the genetically isolated village of Carlantino in southern Italy who were 15-89 years of age at the time of the study. Haplotype analyses were performed and PROP tasting was assessed using a filter paper method. Height, weight, and WC were measured and restrained eating was assessed using a brief questionnaire.


RESULTS
Nontaster females had higher BMI and WC than females who were phenotypic tasters, and this relationship was specific to females with low dietary restraint. Regression analysis showed that BMI declined by 1.7 units across taster groups in females when the model included the PROP by restraint interaction. PROP phenotype was not significantly associated with WC in the regression models. Polymorphisms in TAS2R38 were not associated with BMI or WC in females. Neither TAS2R38 haplotype nor PROP phenotype was strongly related to BMI or WC in males.


CONCLUSIONS
These data support previous findings of a relation between the nontaster phenotype and higher BMI in females that is modified by dietary restraint. Assessment of PROP phenotypes might provide unique information about adiposity that is not captured by haplotype analysis alone.
Tepper
Beverly J
BJ
Department of Food Science, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, New Jersey, USA. tepper@aesop.rutgers.edu
Koelliker
Yvonne
Y
Zhao
Liqiang
L
Ullrich
Natalia V
NV
Lanzara
Carmela
C
d'Adamo
Pio
P
Ferrara
Antonella
A
Ulivi
Sheila
S
Esposito
Laura
L
Gasparini
Paolo
P
D050154:Adiposity / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D031204:Caloric Restriction; D005260:Female; D006239:Haplotypes; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic; D011441:Propylthiouracil / Q000008:administration & dosage; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D012044:Regression Analysis; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013649:Taste / Q000235:genetics*; D000098706:Taste Receptors, Type 2
D043562:Receptors, G-Protein-Coupled; D000098706:Taste Receptors, Type 2; D011441:Propylthiouracil