There is already a superb post about "hot" spices like cayenne/pepper. I am not asking specifically about these spices, but in general all the spices. Spices can include a variety of items like cloves, black peppers, bay leaves, turmeric, ginger, garlic, etc. If you know what "Masala" means then I don't need to elaborate on this. My friend told me that eating too spicy a food can damage organs in the digestive system. I wanted to understand if this can be true?
It may have to do with the chemical structure and how they bind to specific receptors (see: https://en.m.wikipedia.org/wiki/Capsaicin on capsaicin) causing a "sensation of burning" and irritation. It does also seem to directly affect the GI lining:
"Many substances directly irritate the lining of the esophagus and can contribute to heartburn. These include spicy foods, citrus fruits and juices, tomatoes and tomato sauces, cigarette smoke, aspirin, and ibuprofen (with brand names such as Motrin and Advil). Some of these foods can also increase the production of stomach acid and decrease the LES pressure, leading to heartburn." http://www.emedicinehealth.com/script/main/mobileart-emh.asp?articlekey=59146&page=3