A widely held theory that "supertasters" have an unusually high density of taste buds on their tongue to be sensitive to bitter tastes, has been disproved by scientific crowd-sourcing, revealed in a study published in the open-access journal Frontiers in Integrative Neuroscience.
Supertasters are people who can detect and are extremely sensitive to phenylthiocarbamide and propylthiouracil, two compounds related to the bitter molecules in certain foods such as broccoli and kale. Supertasting has been used to explain why some people don't like spicy foods or "hoppy" beers, or why some kids are picky eaters.
The sensitivity to these bitter tastants is partly due to a variation in the taste receptor gene TAS2R38. But some scientists believe that the ability to supertaste is also boosted by a greater-than-average number of "papillae", bumps on the tongue that contain taste buds. Nicole Garneau, Curator and Chair of the Department of Health Sciences, Denver Museum of Nature & Science, and colleagues tested if this is true.
"There is a long-held belief that if you stick out your tongue and look at the bumps on it, then you can predict how sensitive you are to strong tastes like bitterness in vegetables and strong sensations like spiciness," says Garneau. "The commonly accepted theory has been that the more bumps you have, the more taste buds you have and therefore the more sensitive you are."
Over 3000 visitors to the museum's Genetics of Taste Lab volunteered to stick their tongue out so that their papillae could be counted and their sensitivity to phenylthiocarbamide and propylthiouracil measured. In total, 394 study subjects were included in the analysis. Cell swabs from volunteers were taken to determine their DNA sequence at TAS2R38. Results confirmed that certain variations in TAS2R38 make it more likely that somebody is sensitive to bitter, but also proved that the number of papillae on the tongue does not affect increased taste sensitivity.