For thousands of years, philosophers have argued that water has no taste or smell. They said that the sense of taste is a baseline, a starting point, a state of zero. Water was to our tongue what darkness was to our eyes and silence to our ears.
“The natural substance we call water has no taste,” said Aristotle. According to him, water was only responsible for carrying the taste and smell. But scientists have discovered that purified pure water can induce a certain sense of taste. Some said it tasted bitter, while others said it was tasteless, inconsistent and insipid.
By the 1920s, there was growing evidence that the taste of water changes depending on what you ate or drank before it. For example, if you drank a sip of water after eating something acidic, it might taste like sugar. The water you drank after putting a pinch of salt in your mouth could be perceived as bitter.
In the 1960s and 70s, Yale psychologist Linda Bartoshuk published a series of articles on the “aftertaste” of water. Bartoshuk said that the taste cells of a person who eats or drinks something adapt to that stimulus. When water came on top of this flavor, the cells were activated again. We can compare this to seeing the trace of something we looked at before when we look at a white piece of paper. You don’t even need to eat or drink anything to get the same effect.
Bartoshuk discovered that one’s own saliva can also change the taste of water. During the day, your tongue is covered with slightly salty saliva. Because your mouth is used to it, you don’t taste your own saliva and saliva. But when you rinse your mouth with water, your cells taste bitter or slightly sour in the first sip.
For more than 30 years, physiologists had taken it for granted that water has a taste, but only after tasting other things. However, in recent years, a small group of scientists have claimed that the taste of water can be detected by itself. Researchers who set to work in the early 2000s have published data showing that certain parts of the brain (in both humans and guinea pigs) respond specifically to water.
At about the same time, a group at the University of Utah discovered that mammalian taste cells produce a protein called “aquaporin” that allows water to pass through their cell walls. Aquaporins, which are also common in other cell types, allow water to directly stimulate taste cells.
If water has a special appeal to humans and rats, this is not the first time in the animal kingdom. Insects are also known to be fond of water. Scientists know that fruit flies taste chemicals through the hairs that grow from their wings, legs, and trunk. These hairs are connected to a series of neurons that are sensitive to sugary and bitter tastes, as well as to osmotic (transitional) pressure. However, many neuroscientists do not think that a similar mechanism exists in mammals. “You can find a lot of people who firmly believe that water has no taste,” says Patricia Di Lorenzo of Binghamton University. Di Lorenzo’s lab discovered that a rat’s brainstem has neurons that respond only to water, used during the taste-taste process, but his colleagues didn’t take this idea very seriously. “I’m ending my research on water,” he says, “because if no one believes what you say, you move on to other topics.”
Sidney Simon, a physiologist at Duke University, describes a similar experience. He also found cells directly related to water in the rats’ taste cortex. “It is highly likely that there is a water-specific response in mammals,” he says. “While it’s not conclusive proof, it does suggest that.” But other groups failed to find the same cells. This could only be caused by researchers working with animals under anesthesia and measuring responses in the anterior part of the tongue, Simon says. However, it is necessary to look at the back of the mouth to find the cells that taste water. One way or another, it makes perfect sense for water to have a distinctive flavor, according to Simon. “The most common thing in the world is water,” he says. “Your body is 75% water, and so is the planet. Why shouldn’t something like this evolve?”
Source :https://popsci.com.tr/ & Photo: Pineapple Studio/iStock