Demand for nonnutritive sweeteners continues to increase due to their ability to provide desirable sweetness with minimal calories. Acesulfame potassium and saccharin are well-studied nonnutritive sweeteners commonly found in food products. Some individuals report aversive sensations from these sweeteners, such as bitter and metallic side tastes. Recent advances in molecular genetics have provided insight into the cause of perceptual differences across people. For example, common alleles for the genes TAS2R9 and TAS2R38 explain variable response to the bitter drugs ofloxacin in vitro and propylthiouracil in vivo. Here, we wanted to determine whether differences in the bitterness of acesulfame potassium could be predicted by common polymorphisms (genetic variants) in bitter taste receptor genes (TAS2Rs). We genotyped participants (n = 108) for putatively functional single nucleotide polymorphisms in 5 TAS2Rs and asked them to rate the bitterness of 25 mM acesulfame potassium on a general labeled magnitude scale. Consistent with prior reports, we found 2 single nucleotide polymorphisms in TAS2R31 were associated with acesulfame potassium bitterness. However, TAS2R9 alleles also predicted additional variation in acesulfame potassium bitterness. Conversely, single nucleotide polymorphisms in TAS2R4, TAS2R38, and near TAS2R16 were not significant predictors. Using 1 single nucleotide polymorphism each from TAS2R9 and TAS2R31, we modeled the simultaneous influence of these single nucleotide polymorphisms on acesulfame potassium bitterness; together, these 2 single nucleotide polymorphisms explained 13.4% of the variance in perceived bitterness. These data suggest multiple polymorphisms within TAS2Rs contribute to the ability to perceive the bitterness from acesulfame potassium.
Keywords: Project GIANT-CS; bitterness; genetics; noncaloric sweetener; saccharin; taste phenotype.