It’s a common experience: drinking water after mint gum often makes the water feel significantly colder than it truly is. This sensation is not due to the water’s actual temperature dropping, but rather an interaction within our sensory system. This feeling is a sensory illusion created by a specific chemical compound found in mint products.
The Role of Menthol
The primary chemical responsible for this cooling sensation is menthol. This organic compound occurs naturally in mint plants like peppermint and spearmint. Menthol is widely utilized across many products due to its characteristic cooling properties, including oral hygiene products like toothpaste and chewing gum, as well as in medicinal balms and flavorings.
Menthol is a cyclic terpene alcohol, which means it is a specific type of molecule derived from plants. When consumed or applied, this molecule interacts with the body’s sensory receptors. Its widespread use stems from its ability to create a refreshing and cooling effect, even without any actual temperature change.
Menthol’s Cooling Mechanism
The cooling sensation from menthol arises from its interaction with a specific protein in nerve cells called the Transient Receptor Potential Melastatin 8 (TRPM8) receptor. This TRPM8 receptor functions as an ion channel, responsible for detecting cold temperatures. Found in sensory neurons, especially in the mouth and skin, these receptors send signals to the brain when activated by cold.
When menthol molecules bind to the TRPM8 receptors, they cause the receptor’s ion channel to open. This opening allows ions to flow into the cell, generating an electrical signal that is then transmitted to the brain. The brain interprets this signal as a sensation of cold, even though there is no actual drop in temperature.
Why Water Amplifies the Sensation
Drinking water after mint gum intensifies this perceived coldness. Water, as a liquid, helps spread the menthol molecules throughout the mouth and throat more effectively. This wider distribution allows more menthol to activate a larger number of TRPM8 receptors across a broader surface area.
Water also has a temperature cooler than body temperature, which can activate TRPM8 receptors on its own to a minor degree. This mild activation from the water combines with the menthol-induced activation, leading to a more pronounced cold signal sent to the brain. The combination of increased menthol distribution and the water’s coolness creates an amplified sensation, making the water feel significantly colder than its true temperature.