Taste: Supertasters

Although there are individual differences in the extent to which we are sensitive to all taste qualities, such variation is most pronounced for bitterness. Human responses to bitter thiourea compounds, in particular phenylthiocarbamide (PTC) and [Page 965]6-n-propylthiouracil (PROP), have been extensively studied for several decades, and it is well established that 25 to 30% of Caucasian populations are highly insensitive to their taste (non-tasters), although this proportion does vary across cultures. Among those who find PTC/PROP bitter (tasters), there is also considerable variation in both thresholds and suprathreshold ratings of intensity. In 1992, Linda Bartoshuk and colleagues at Yale University reported that a subgroup of tasters (estimated also as 20–25% of the population, or around a third of all tasters) rated PROP as profoundly bitter. Such supertasters may have been previously overlooked, due to the initial widespread use of detection (threshold) criteria for PTC/PROP taster group classification, which gave no indication of variation in suprathreshold responses. This entry discusses the genetic variations, the perception of somatosensory qualities, and food preferences and health implications as they relate to supertasters.