The capability to taste calcium has now been discovered in mice. With these rodents and humans sharing many of the same genes, the new finding suggests that people might also have such a taste.
The four tastes we are most familiar with are sweet, sour, salty and bitter. Recently scientists have discovered tongue molecules called receptors that detect a fifth distinct taste – “umami,” or savory.
“But why stop there?” asked researcher Michael Tordoff, a behavioral geneticist at the Monell Chemical Senses Center in Philadelphia. “My group has been investigating what we believe is another taste quality – calcium.”
So assuming the human palate can detect calcium, what does the mineral taste like?
“Calcium tastes calcium-y,” Tordoff said. “There isn’t a better word for it. It is bitter, perhaps even a little sour. But it’s much more because there are actual receptors for calcium, not just bitter or sour compounds.”
One way we might regularly perceive calcium is when it comes to minute levels found in drinking water.
“In tap water, it’s fairly pleasant,” Tordoff said. “But at levels much above that, the taste becomes increasingly bad.”
There may be a strong link between the bitterness of certain vegetables and their calcium level. High-calcium vegetables include collard greens, bok choy, kale and bitter melon. One reason some people might avoid these veggies, Tordoff suggests, is because of their calcium taste.
Ironically, while milk and other dairy products are loaded with calcium, the mineral tends to bind to fats and proteins, which prevents you from tasting it in these foods.
A taste receptor designed specifically for calcium makes sense for our survival, since the mineral is key to cell biology and good bones. Low calcium intakes have been implicated in several chronic diseases in people, including osteoporosis, obesity and hypertension.
“Many animals have a specific calcium appetite, which implies they can detect the mineral and consume sufficient quantities of it to meet their needs,” Tordoff said.
Tordoff and his colleagues detailed their findings Aug. 20 at the national meeting of the American Chemical Society in Philadelphia.