The Secret Power of Mint

Chocolate. Ice cream. Cookies. Coffee. Tea. Chewing gum.

They can all feature mint flavorings.

In the 21st century, where delectable chemistry can produce seemingly unending concoctions, it’s easy to forget that many of our seasonings and spices are plants, not just artificial flavors. Even chocolate, which can be quite delicious mixed with mint, is made from beans. Vanilla comes from orchids. Today, the word “mint” might evoke Andes, green ice cream, or red-and-white candy swirls, but mints originally belong to the botanical world.

Andes Mints - photo by Evan-Amos
Peppermint candy cane - photo by Evan-Amos
Mint chocolate chip ice cream - photo by Famartin

The Lamiaceae family contains a cornucopia of the planet’s most aromatic and tasty herbs, including basil, rosemary, sage, marjoram, oregano, thyme, lavender, and mints. The genus Mentha contains all the natural mints and a slew of hybrid cultivars. So much crossover between species has occurred that scientists aren’t sure how many exist, as the distinctions become almost subjective. Somewhere between 13 and 24 species persist, though the cultivars bring the number of phenotypically distinct mints to a much higher number, perhaps as many as 3,000.

The type species of the genus is Mentha spicata, better known as spearmint. The earliest known usage of the word “mint” refers to spearmint, which populated Europe and Asia. Greek mythology contains Minthe, a nymph who was transformed into spearmint by Persephone or Demeter.

Mint plants are perennial herbs. They are distinctly aromatic, and the oils from the leaves produce potent flavorings and scents. Spearmint continues to be one of the dominant mint flavors, along with peppermint. Interestingly, the latter is a hybrid, a crossover between spearmint and watermint. Another common “mint” flavoring – wintergreen – is not a mint at all.

Spearmint - photo by Simon Eugster
Peppermint - photo by VS6507

One notable attribute of many mint flavorings is the ability to feel cool to human mouths. Mouthwashes, toothpastes, and aromatherapy substances lean on this characteristic to make breath not only smell nice but feel fresh, too.

Unless one is eating ice cream, ingesting mint does not alter the temperature of one’s tongue. So, why does a mouth feel cold when mint is involved? The secret power is in an organic compound called menthol.

Menthol's chemical diagram - graphic by Daveryan
Pure menthol - photo by Miansari66

One of the human body’s networks of neurons detects touch and temperature and produces pain. Called the somatosensory system, the neurons employ proteins to detect certain signals. When the signal – heat, coldness, touch, etc – hits the proteins, they open and close ion channels that allow matter to pass through cell membranes. If the tunnel is open and external ions enter the system, an electrical signal goes to the brain, triggering the sensations we know so well.

The protein that detects coldness is called TRPM8. Slurp vanilla ice cream and TRPM8 starts a chain that tells the brain the tongue is cold. As it turns out, something else triggers TRPM8: menthol. The substance in mint tricks our somatosensory system into thinking something cold is inside our mouths!

Evolutionary biologists believe mint plants developed the ability to create menthol as they evolved over millions of years. Since menthol has a specific effect on the taste buds of creatures that munch on mint, the plants that developed menthol might have found themselves less likely to be lunch. Eventually, the mints with menthol survived, packed with an inherent deterrent.

This evolutionary plotline is similar to that of another plant. Chili peppers feel hot to humans because of a molecule called capsaicin, which does not raise the temperature but fools the proteins into feeling warm. Mint and chili peppers were less likely to be eaten because of their magic molecules.

Even though these plants trick our biology, we can use the technology to our advantage. The nerve endings of our eyes, noses, and mouths are close to the skin surface, which leaves them vulnerable to sensations. Your mouth might “burn” when you eat a pepper, the result of anatomy. But, if you have a sore throat, some menthol can produce a cooling sensation to temporarily mask the yuckiness. The same is true for an inflamed nose. Breathe in menthol vapors and fleeting relief might be yours.

Or, if you really want to flex your neurons, mint chocolate chip ice cream will work your TRPM8 on two levels!

Further Reading and Exploration

Mentha L. – Plants of the World Online

Mints – Botanical

mint – Encyclopedia Britannica

Why Does Mint Make Your Mouth Feel Cool? – Live Science

DUDE, YOU GOT SOME GUM? – Science Creative Quarterly

How Peppermint Tricks Us Into Feeling (Deliciously) Cold – NPR

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