Why does mint make your mouth feel cold and pepper makes it burn: scientists explain
Mint and pepper are a special type of food that people like not because of their taste, but because of the effect they have on the receptors in the mouth (and beyond). Mint, if you chew a sprig or rub the plant's juice on your skin, creates a feeling of slight coldness, while pepper, under the same conditions, causes a feeling of warmth. Have you ever wondered why this happens?
Science Notes decided to tell you more about it. It turns out that it's all about brain chemistry and certain substances contained in these foods.
Why is mint cold?
Low temperatures change the shape of the protein, which is abbreviated as TRPM8. It stands for Transient receptor potential cation channel subfamily M (melastatin) member 8, and its simpler name is cold and menthol receptor. This protein can be found in the nerve cells of the skin and taste buds.
It works like this: an organic compound called menthol, which is found in various types of mint, binds to TRPM8 and changes the shape of the protein. This opens up ion channels through which sodium (Na+) and calcium (Ca2+) ions begin to enter the nerve cell. This changes the electrical charge of the neuron and it begins to send a distorted signal to the brain, which the latter interprets as a feeling of cold. The reason is that the brain receives the same signal from the same cell when it really reacts to touching something cold.
The difference between the effect of the substance and the temperature is that menthol does not immediately separate from TRPM8. It temporarily increases the sensitivity of neurons, so the effect of cold does not go away immediately. That's why if you drink cold water after eating a mint lollipop, chewing mint gum, or brushing your teeth with mint-flavored toothpaste, the water will feel colder than it actually is.
Menthol is not the only chemical that binds TRPM8 and causes a cold sensation. Thymol (a phenol found in thyme and some other plants), sugar alcohols, and many pesticides can have a similar effect. Scientists do not know exactly what this effect is for, but they assume that the plants that produce them protect themselves from microbes and pests with the help of the corresponding substances.
How does pepper cause a burning sensation?
The substance responsible for the burning properties of pepper is called capsaicin. And the receptor with which it interacts is TRP-VR1. In general, its mechanism of action is similar to TRPM8, but the brain eventually receives a misleading signal about high temperature rather than low. And capsaicin, just like menthol, is able to deceive its receptor but cause the opposite sensation. And the strength of the signal it creates is so powerful that water with the addition of hot pepper can seem hot even if it is at room temperature or cold.
What happens when you combine mint and pepper?
You've probably already wondered what would happen if you activated both receptors at the same time by mixing menthol with capsaicin. So far, scientists have found that eating mint can neutralize the burning sensation of pepper, but only if you eat it first and then immediately eat something spicy. If you use menthol after capsaicin, it may not help.
Currently, the combination of these two substances is used in local anesthetic preparations. When applied to the skin at the same time, menthol and capsaicin cause a cooling and burning sensation, which provokes numbness. In addition, both substances accelerate blood circulation in the skin.
Earlier, OBOZREVATEL told what makes women and men taste alcohol differently.