Just about everyone has tasted something with mint at least once. Gum, toothpaste, even ice cream all come in a mint flavor, and it makes your mouth feel cool. Have you ever wondered why does mint make your mouth feel cool? If you have, you should know that the fact that mint is cooling is a biochemical success story in the plant world.
A Defense mechanism
According to Paul Wise, an associate member at the Monell Chemical Senses Center in Philadelphia, the plant evolved compounds to use as a defense mechanism. Chilies are similar. They have capsaicin that is hot, and mint has menthol, which is cooling. He believes that the mint plant may have evolved compounds to use as a defense mechanism, and through natural selection, they found something that worked. Scientists believe that the mint plants’ ancestors produced the minty chemical to deter predators.
Less Likely To Be Eaten
According to Paul, the plants that produced these compounds were less likely to be eaten. This meant that they were able to survive long enough to reproduce and spread their seeds. They were able to pass their genes to other generations, which why the plant is so plentiful. You can walk into just about any hardware store or plant store and find seeds for mint plants. This is why the plants are cooling, but why does it make your mouth feel cold? There is a good reason for this.
The answer to this question is relatively simple. The menthol in the plant tricks your body into feeling cool, even if it isn’t. Both menthol and capsaicin affect the sensory receptors in your brain. These receptors monitor things like touch, pain, and temperature. It is also known as the somatosensory system. It is a complex network of neurons, and it is different than the system that your body uses to taste and smell.
According to Seok-Yong Lee, an associate professor of biochemistry at Duke University, there are neurons located under the skin that can sense different sensations such as hot and cold. These neurons use proteins embedded in the cell membranes to monitor the environment. The proteins control a group of tiny tunnels called ion channels. They allow matter to pass through the cell membrane. These channels will stay closed until the receptor protein detects the stimulus. If the receptors sense heat or the right chemical, the proteins turn on an then allow the ions to penetrate the cell membrane. When the ions are turned on, they trigger a tiny electric signal, which they then relay to the brain.
When the signal reaches the brain, it is like an electrochemical telegram that is telling the brain that the tongue is cold. Most receptor proteins were designed to top the ion channels. There is one protein called TRPM8, and it is pronounced “trip M 8.” It is associated with the coldness, and when you lick an ice cream cone, it goes wild.
The reason that mint makes your mouth feel cold is that the menthol molecules cause the TRPM8 receptors to open the channels, and sent a message to the brain. They cause the brain to interpret a tiny pulse of electricity and tells the tongue that its cold, even when it isn’t. The cooling from the mint is just a sensation. The high concentration in menthol can cause local inflammation, which would result in a very slight increase in temperature, but it is mostly sensation.
Not Much Evidence
Scientists can only speculate why TRPM8 is sensitive to the coldness of menthol. This is because there is no substantial evidence yet. It has only been a few months since the study was published in the Journal of Science. There is more research that needs to be done if the theory is going to be proven.
According to Professor Lee, if this is going to be more than just a theory, more testing will be necessary. It takes time to turn a hypothesis into an argument, and Professor Lee has taken on the challenge.
Think About It
The next time you sit down with a bowl of mint chocolate chip ice cream, remember that it isn’t just the ice crystals that make it feel cold. The mint has a lot to do with it. It doesn’t change the temperature of your tongue; however. That is what the ice does. The mint will give you the sensation of being cold, without dropping the temperature of your mouth. You should also respect the mint plant. For a plant to have its own defense system to allow it to thrive and grow all over the world is pretty incredible. There aren’t too many plants out there with their own defense mechanism.