We’ve all done it. You’re chewing some chewing gum, reach for your glass of water, take a swig and… whoa. Why does the water taste so cold?
Well, we can safely tell you that it’s not magic. There is some actual science behind it, and it’s kinda cool.
At the heart of the effect is a protein called the transient receptor potential cation channel subfamily M member 8. If you can’t remember that, it’s more simply called TRPM8.
It’s found in our cold-sensing nerve cells, and it’s responsible for moving ions across cell membranes. However, it only activates in cold temperatures, alerting the brain that the temperature has dropped.
It does this by allowing in sodium and calcium ions when it gets colder. This sends a current from the membrane of the nerve cell, and hey presto – the brain knows it's cold.
But it’s not just temperature that triggers TRPM8. Menthol, an organic chemical found in peppermint and mint oils, can also activate TRPM8. We don’t quite know how it does this but, well, it does.
This means that when you eat something minty, which contains menthol, TRPM8 is tricked into opening its doors and lets in sodium and calcium ions. A signal is then incorrectly sent to your brain telling it that the temperature has dropped.
It’s not just when it is ingested, too. Applying menthol to your skin, such as in a shower gel, makes your skin go cold and numb. It’s the same effect taking place here, which can also help reduce inflammation.
Something similar works with hot things, too. Ever wondered why chili peppers make you feel hot? Well, that’s due to compounds called capsaicinoids, which bind to receptors that make your brain respond to pain from heat, causing things like teary eyes and a runny nose. This can also, well, make you feel high.
So the next time you pop that mint in your mouth, just remember that while it might taste great, your poor body is panicking as it thinks the temperature is dropping. A least it makes that gulp of water taste all the more refreshing.