Have you ever noticed that burning feeling you get from eating spicy food? Capsaicin, the stuff that makes chillies hot, binds to our nociceptiors; nociceptors are also responsible for detecting heat. Also, you might have figured out that drinking water doesn’t really help. That’s because capsaicin does not dissolve well in water, but it does dissolve well in fats. So all is not lost, as caseins, such as those found in milk have both fat-soluble and water-soluble parts. Multiple caseins can surround a capsaicin molecule with their fat-soluable part, and have their water-soluable parts sticking out so that the whole big lump of casein-capsaicin (this structure is known as micelle) can be dissolved and wash down your stomach, clearing your noiceptors and leaving your mouth burn free!
the Runaway Lab Book 