Proteins that help sense sweet and spice also help mice detect iron, zinc, copper
Yukon Cornelius isn’t the only one with a taste for metals. While most people probably can’t find silver and gold by nibbling snow, as Cornelius seems to do in the Rudolph movie*, new research shows that taste buds can detect iron, zinc, copper, magnesium and other metals.
The source of metallic taste has long been elusive, but a study in the Feb. 25 Journal of Neuroscience traces the sensation to a combination of proteins used in detecting sweetness and the pain of red-hot chili peppers, and other as-of-yet unidentified proteins.
Scientists used to believe that there were only a handful of tastes the tongue could register — sweet, sour, bitter, salty and umami, a delicious, meaty taste found in monosodium glutamate, Parmesan cheese and portobello mushrooms. Scientists define a taste as something that is detected by a specific combination of proteins in taste buds, as distinct from a flavor that results from a combination of tastes and odors.