Supertaster
A supertaster is a person who experiences the sense of taste with far greater intensity than average, with some studies showing an increased sensitivity to bitter tastes. It may be a cause of selective eating. History. The term originated with experimental psychologist Linda Bartoshuk, who has spent much of her career studying genetic variation in taste perception. In the early 1980s, Bartoshuk and her colleagues noticed some individuals tested in the laboratory seemed to have an elevated taste response and took to calling them supertasters. This increased taste response is not the result of response bias or a scaling  artifact, but appears to have an anatomical or biological basis. Phenylthiocarbamide. In 1931, Arthur L. Fox, a DuPont chemist, discovered that some persons found phenylthiocarbamide (PTC) to be bitter while others found it tasteless. At the 1931 meeting of the American Association for the Advancement of Science, Fox collaborated with Albert F. Blakeslee, a geneticist, to have attendees taste PTC: 65% found it bitter, 28% found it tasteless, and 6% described other taste qualities. Subsequent work revealed that the ability to taste PTC was genetic. Propylthiouracil. In the 1960s, Roland Fischer was the first to link the ability to taste  PTC, and the related compound propylthiouracil (PROP), to food preference and body type. Today, PROP has replaced PTC in taste research because of a faint sulfurous odor and safety concerns with PTC. As described above, Bartoshuk and colleagues discovered that the taster group could be further divided into medium tasters and supertasters. Research suggests 25% of the population are nontasters, 50% are medium tasters, and 25% are supertasters. Cause. The cause of this heightened response is unknown, although it is thought to be related to the presence of the TAS2R38 gene, the ability to taste PROP and PTC, and, at  least in part, due to an increased number of fungiform papillae. Any evolutionary advantage to supertasting is unclear. In some environments, heightened taste response, particularly to bitterness, would represent an important advantage in avoiding potentially toxic plant alkaloids. In other environments, increased response to bitterness may have limited the range of palatable foods. In addition, it's also thought that environmental causes are likely to play a substantial role in supertaste. The exact mechanisms by which these may act are still unknown. TAS2R38. The bitter-taste-receptor gene TAS2R38 has been associated with the ability to taste PROP and PTC ; but it cannot completely explain supertasting. Still, the T2R38 genotype has been linked to a preference for sweetness in children, avoidance of alcoholic beverages, increased prevalence of colon cancer (because of inadequate vegetable consumption) and avoidance of cigarette smoking. Prevalence. Women. Women are more likely to be supertasters, as are those from Asia, South America, and Africa. Female supertasters have a lower body mass index and predominant cardiovascular health. This can be due to the fact that supertasters do not have a high predilection for sweet or high-fat foods. Identification. Supertasters were initially identified on the basis of  the perceived intensity of propylthiouracil (PROP) compared to a reference salt solution. Supertasters consume more salt in comparison to those with average taste. Because supertasters have a larger sense of taste than medium or non-tasters, this can cause scaling artifacts. Subsequently, salt has been replaced with a non-oral gustatory standard. Therefore, if two individuals rate the same gustatory stimulus at a comparable perceptual intensity, but one gives a rating twice as large for the bitterness of a PROP solution, the experimenter can be confident the difference is real and not merely the result of how the person is  using the scale. Today, there is a phenylthiocarbamide (PTC) test strip that is used to help determine if someone is a low-taster. The general population tastes this as bitter about 75% of the time. Many studies do not include a cross-modal reference and simply categorize individuals on the basis of the bitterness of a concentrated PROP solution or PROP impregnated paper. Supertasters tend to have more fungiform papillae and pain receptors than tasters and non-tasters. It is also possible to make a reasonably accurate self-diagnosis at home by careful examination of the tongue and looking for  the number of fungiform papillae. Blue food dye can make this easier. Being a supertaster or non-taster is part of normal variation in the human population, as are eye color and hair color, so no treatment is needed. Specific food sensitivities. Although individual food preference for supertasters cannot be typified, documented examples for either lessened preference or consumption include: Other foods may also show altered patterns of preference and consumption, but only indirect evidence exists: Along with citation 5: Title: Olfaction and taste. Di Lorenzo, P.M., and Youngtentob, S.L. 2010. In M. Gallagher and R.J. Nelson (Eds.), Handbook  of psychology, (Vol. 3): Biological psychology. New York: Wiley.