Even in the coldest months, we relish the refreshing, icy taste of peppermint — in seasonal treats like peppermint bark, peppermint schnapps, even peppermint beer.
We have the chemical menthol to thank for that deliciously cool mouth-feel of peppermint. And scientists now know that menthol actually tricks our brains and mouths into the cool sensation because menthol activates the same receptor on nerve endings that's involved in sensing cold, says David McKemy, a neurobiologist at the University of Southern California.
As McKemy explains in a video about peppermint out this month from USC, thanks to this neat trick of nature, researchers were able to use menthol to better understand how our nervous system senses and reacts to cold. His team found a protein which is "a trigger on cold sensing nerve fibers to send an electrical signal to the brain to let you know that you're feeling cold."
"It's incredible how nature and plants have evolved to have these effects," McKemy tells The Salt.
For some reason, we seem to be hard-wired to enjoy the refreshing, cooling sensation of menthol in our mouths. Research shows that menthol's effects on cold receptors may satiate thirst, ease breathing and help us feel alert — which helps explain why it's so popular not just in candy but also in cigarettes and cold medicine.
As McKemy notes, cold drinks can satiate thirst faster than water that's room temperature, and it is easier to breath when the air is cool. A 1990 study by psychologists found that peppermint may also help us feel more alert and focused.
The reason we got hooked on candy canes and other peppermint treats this time of year is most likely cultural – and coincidental, says Ryan Berley, owner of Shane Confectionery in Philadelphia, where handmade peppermint candy canes sell by the hundreds in the wintertime. Berley researched the history of peppermint candy for an exhibition on sugar and confections he curated last year at Philadelphia's Independence Seaport Museum
"First of all, hard candies could only be successfully made in the winter months," Berley says. At least in the days before air conditioning, summer humidity would spoil the texture of the candy — so these sorts of sweets were a wintertime treat.
And peppermint has always been a common candy flavor because it doesn't cook off during the process of making candy, Berley says. "Mint flavored candies go back hundreds of years to Europe and probably to the Middle East before that."
At some point — though Berley says it's unclear when exactly — confectioners began adding peppermint to candy canes, a Christmastime sweet.
Legend has it that the candy cane was designed in the 17th century by a German choirmaster. "He asked a candy maker to make a stick into a shepherd's crook to remind children of the nativity scene," Berley says. "So now it's got this Christmas association."