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Supertasters are individuals whose sense of taste for certain flavors and foods, such as chocolate, is far more sensitive than the average person. [1] The term originated with experimental psychologist Linda Bartoshuk and is not the result of response bias or a scaling artifact but appears to have an anatomical or biological basis.
Over the past two decades, the study of many differences in oral sensation has grown to encompass the idea of supertasting. Originally identified as the heightened response to the suprathreshold bitterness of concentrated propylthiouracil (PROP), [2] the contemporary view supports that supertasting encompasses an elevated response to all taste qualities. [3] [4]
Reports of variations in human taste perception date back to 1888. [5] The major advance in understanding human taste variation came in 1931 with the discovery of "taste-blindness" specifically for thiourea compounds, when Arthur L. Fox, a chemist at DuPont, discovered that some people found phenylthiocarbamide (PTC) bitter, while others found it tasteless. [6] [7]
Fox describes the event:
Some time ago the author [Arthur L. Fox] had occasion to prepare a quantity of phenyl-thio-carbamide, and while placing it in a bottle the dust flew around in the air. Another occupant of the laboratory, Dr. C. R. Noller, complained of the bitter taste of the dust, but the author, who was much closer, observed no taste and so stated. He even tasted some of the crystals and assured Dr. Noller they were tasteless but Dr. Noller was equally certain it was the dust he tasted. He tried some of the crystals and found them extremely bitter. [8]
At the 1931 American Association for the Advancement of Science (AAAS) meeting, Fox collaborated with Albert F. Blakeslee, a geneticist, to have participants taste PTC: 65% found it bitter, 28% found it tasteless, and 6% described other taste qualities. Subsequent studies established that the ability to taste PTC was heritable (Mendelian recessive), indicating a genetic component to taste sensitivity. [9] [10]
In the 1960s, Roland Fischer was the first to link the ability to taste PTC, and the related compound propylthiouracil (PROP) to food preference, diet, and calorie intake. [11] Today, PROP has replaced PTC for research because of a faint sulfurous odor and safety concerns with PTC. [12] In the 1990s Linda Bartoshuk and colleagues discovered that the taster group could be further divided into medium tasters and supertasters. [13] [14] Research suggests 25% of the population are non-tasters, 50% are medium tasters, and 25% are supertasters. [2] [15]
As a result of hundreds of studies exploring the detection threshold variation in taste sensitivity, the ability to taste the bitter compound phenylthiocarbamide (PTC) has become one of the best-known Mendelian traits in human populations, ranking alongside eye color and blood type in the canon of classic examples. [16]
In 2003, a significant breakthrough occurred when allelic variation in the bitter receptor gene TAS2R38 was identified as the molecular basis for differences in PTC detection thresholds. This gene encodes a receptor on the tongue that binds to bitter compounds, influencing how strongly an individual perceives the taste of these substances. [17] The discovery of TAS2R38's role in taste perception was quickly extended to include sensitivity to propylthiouracil (PROP). [18] Associations between TAS2R38 and the number of fungiform papillae (FP) were suspected. However, a causal relationship with the supertaster phenomenon has not been established. [19]
Molecular genetics indicate that TAS2R38 alleles cannot explain supertasting. [19] This seems intuitive, as polymorphisms in a specific bitter receptor gene are unlikely to account for heightened responses across multiple taste qualities, oral somatosensation, and retronasal olfaction. [20] [21]
In addition, environmental causes may play a role in sensitive taste. The exact mechanisms by which these causes may manifest, as well as possible evolutionary advantages to elevated taste sensitivity, are still unknown. [22] [23] No clearcut benefit to the trait has been established: in some environments a heightened taste response, particularly to bitterness, would represent an important advantage in avoiding potentially toxic plant alkaloids; however, an increased response to bitterness may limit approach behavior for various palatable foods.
Moreover, the TAS2R38 genotype has been linked to a preference for sweetness in children, [24] avoidance of alcoholic beverages, [25] increased prevalence of colon cancer (because of inadequate vegetable consumption), [26] and avoidance of cigarette smoking. [27]
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Women are more likely to be supertasters, as are those from Asia, South America, and Africa. [28] Female supertasters tend to have a lower body mass index and better cardiovascular health. This could be because supertasters may not have a high predilection for sweet or high-fat foods compared to the average person. [29]
The tongue's fungiform papillae can be revealed with blue food dye.
Supertasters were initially identified based on the perceived intensity of propylthiouracil (PROP) compared to a reference salt solution. Supertasters consume more salt in comparison to those with average taste. [30] 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. [31] Today, a phenylthiocarbamide (PTC) test strip is used to help determine if someone is a low taster. The general population tastes this as bitter about 75% of the time. [32]
Many studies do not include a cross-modal reference and categorize individuals based on the bitterness of a concentrated PROP solution [33] [34] or PROP-impregnated paper. [35] Supertasters tend to have more fungiform papillae and pain receptors than tasters and non-tasters. [36] It is also possible to make a reasonably accurate self-diagnosis at home by carefully examining the tongue and looking for the number of fungiform papillae. [37]
This section needs additional citations for verification .(June 2024) |
Although individual food preferences for supertasters cannot be typified, documented examples for either lessened preference or consumption include:
Phenylthiocarbamide (PTC), also known as phenylthiourea (PTU), is an organosulfur thiourea containing a phenyl ring.
Brassica oleracea is a plant species from family Brassicaceae that includes many common cultivars used as vegetables, such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy cabbage, kohlrabi, and gai lan.
Propylthiouracil (PTU) is a medication used to treat hyperthyroidism. This includes hyperthyroidism due to Graves' disease and toxic multinodular goiter. In a thyrotoxic crisis it is generally more effective than methimazole. Otherwise it is typically only used when methimazole, surgery, and radioactive iodine is not possible. It is taken by mouth.
Aftertaste is the taste intensity of a food or beverage that is perceived immediately after that food or beverage is removed from the mouth. The aftertastes of different foods and beverages can vary by intensity and over time, but the unifying feature of aftertaste is that it is perceived after a food or beverage is either swallowed or spat out. The neurobiological mechanisms of taste signal transduction from the taste receptors in the mouth to the brain have not yet been fully understood. However, the primary taste processing area located in the insula has been observed to be involved in aftertaste perception.
TAS2R16 is a bitter taste receptor and one of the 25 TAS2Rs. TAS2Rs are receptors that belong to the G-protein-coupled receptors (GPCRs) family. These receptors detect various bitter substances found in nature as agonists, and get stimulated. TAS2R16 receptor is mainly expressed within taste buds present on the surface of the tongue and palate epithelium. TAS2R16 is activated by bitter β-glucopyranosides
Chemesthesis is the detection of potentially harmful chemicals by the skin and mucous membranes. Chemesthetic sensations arise when chemical compounds activate receptors associated with other senses that mediate pain, touch, and thermal perception. These chemical-induced reactions do not fit into the traditional sense categories of taste and smell.
Rachel Sarah Herz is a Canadian and American psychologist and cognitive neuroscientist, recognized for her research on the psychology of smell.
A taste receptor or tastant is a type of cellular receptor that facilitates the sensation of taste. When food or other substances enter the mouth, molecules interact with saliva and are bound to taste receptors in the oral cavity and other locations. Molecules which give a sensation of taste are considered "sapid".
Taste receptor 2 member 38 is a protein that in humans is encoded by the TAS2R38 gene. TAS2R38 is a bitter taste receptor; varying genotypes of TAS2R38 influence the ability to taste both 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC). Though it has often been proposed that varying taste receptor genotypes could influence tasting ability, TAS2R38 is one of the few taste receptors shown to have this function.
Danielle Renee Reed is an American geneticist employed at the Monell Chemical Senses Center in Philadelphia, Pennsylvania. She is most notable for her papers regarding genetic variation in taste and obesity in mice and humans.
An acquired taste is an appreciation for something unlikely to be enjoyed by a person who has not had substantial exposure to it. It is the opposite of innate taste, which is the appreciation for things that are enjoyable by most people without prior exposure to them.
Dr. Alexander Bachmanov studied veterinary medicine at the Saint Petersburg Veterinary Institute, Russia (1977-1982), received his Ph.D. in biological sciences from the Pavlov Institute of Physiology in Saint Petersburg, Russia in 1990. He completed postdoctoral fellowships at the Physiological Laboratory at Cambridge University in 1993 and at the Monell Chemical Senses Center, Philadelphia, Pennsylvania, in the United States from 1994 to 1997. He later joined Monnell's faculty.
Dr. Michael G. Tordoff is a psychobiologist working at the Monell Chemical Senses Center. His research deals with the genetics and physiology of taste and nutrition. His early work addressed (a) how and what animals learn about the value of their food, (b) how artificial sweeteners influence appetite and body weight, (c) how salt intake is regulated, and (d) how dietary calcium influences salt intake. Recently, he has been investigating calcium taste and appetite. He is the primary proponent of the notion that calcium is a basic taste, equivalent to sweet, sour, salty, and bitter.
The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception stimulated when a substance in the mouth reacts chemically with taste receptor cells located on taste buds in the oral cavity, mostly on the tongue. Taste, along with the sense of smell and trigeminal nerve stimulation, determines flavors of food and other substances. Humans have taste receptors on taste buds and other areas, including the upper surface of the tongue and the epiglottis. The gustatory cortex is responsible for the perception of taste.
Research into food choice investigates how people select the food they eat. An interdisciplinary topic, food choice comprises psychological and sociological aspects, economic issues and sensory aspects.
The evolution of bitter taste receptors has been one of the most dynamic evolutionary adaptations to arise in multiple species. This phenomenon has been widely studied in the field of evolutionary biology because of its role in the identification of toxins often found on the leaves of inedible plants. A palate more sensitive to these bitter tastes would, theoretically, have an advantage over members of the population less sensitive to these poisonous substances because they would be much less likely to ingest toxic plants. Bitter-taste genes have been found in a host of vertebrates, including sharks and rays, and the same genes have been well characterized in several common laboratory animals such as primates and mice, as well as in humans. The primary gene responsible for encoding this ability in humans is the TAS2R gene family which contains 25 functional loci as well as 11 pseudogenes. The development of this gene has been well characterized, with proof that the ability evolved before the human migration out of Africa. The gene continues to evolve in the present day.
A taster is a person, by means of a human genotype, who is able to taste phenylthiocarbamide (PTC) and its derivative 6-n-propylthiouracil (PROP). PTC tastes bitter to many people (tasters) but is tasteless to others (non-tasters).
PTC tasting is a classic genetic marker in human population genetics investigations.
Dennis T. Drayna is an American human geneticist known for his contributions to stuttering, human haemochromatosis, pitch, and taste. He is currently the Section Chief of Genetics of Communication Disorders at the U.S. National Institute for Deafness and Other Communication Disorders.
A variety of behaviors whereby people are highly selective in what they eat and do not eat are known as picky eating or selective eating. Selective eating is common in younger children and can also sometimes be seen in adults.