Educator Rose Eveleth explains what makes certain foods spicy, how the body reacts to that spice and why certain people enjoy the burn of spicy foods more than others in “The Science of Spiciness“, a Ted-Ed animated lesson.
Even though we say something is spicy, spicy is not a taste like sweet, salty or sour. Instead what’s really happening is that certain compounds in food activate the sensory neurons called “polymodal nociceptors“. You have these all over your body, including your mouth and nose and they’re the same receptors that are activated by extreme heat. So when you eat a chili pepper, your mouth feels like it’s burning because your brain actually thinks it’s burning. The opposite happens when you eat something with menthol in it, the cool minty compound is activating your cold receptors. When these heat sensitive receptors are activated, your body thinks it’s in contact with a dangerous heat source and reacts accordingly.