BITTER TASTE GENETICS AND FOOD PREFERENCE IN ITALIAN POPULATION

Objective: To investigate the possible role of the polymorphic bitter taste gene, TAS2R38, known to be involved in the perception of the bitter synthetic chemical phenylthiocarbamide (PTC), in influencing food preference and body mass index(BMI). Methods: up to now more than 1500 university students (17-25 years old) at Catania, Cosenza, Rome, Palermo, Pisa, Parma, Chieti, Trento University have been enrolled in the study. DNA was extracted from saliva, and genotyped by TaqMan assay for the most frequent polymorphism (PAV/AVI) of TAS2R38 gene. A possible association between genotype and food preference was assessed by administering a detailed questionnaire for food preferences and life style. Results: 1) the entire population was found to be in Hardy –Weimberg equilibrium. 2) No significant difference in allele frequencies between Centre and South Italy was observed, neither between the isolated population of Garfagnana and the rest of Italy. 3) A significant difference was observed considering rare aplotypes. 4) A good correlation (80%)between TAS2R38 polymorphism and capability to assess PTC bitterness was observed. 5) A suggestive, but non statistically significant correlation between BMI and genotype, particularly in male, (p=0.08) was obtained. 6) An indication that TAS2R38 polymorphism (genotype) is associated with the preference of some food such as: bitter chocolate (p=0.02), sprouts (0.09), onion (0.03), whipped cream(p=0.09) was obtained. 7) In addition, the indication that bitter PTC assessment capability (phenotype) can be associated with the preference or disliking of cabbage(p=0.015); bitter chocolate (p=0.10) sausages (p=0.05); garlic (p=0.08); onion(p=0.07); citrus fruits (0.08), strong cheese (p=0.06) was also obtained. Conclusions: we are aware that TAS2R38 is just one of the 25 (or more) human polymorphic gene involved in the perception of bitter taste or astringency of foods and that it appears to be particularly associated to PTC bitterness.