In individuals with celiac disease, the immune system mistakenly identifies gluten as a threat. When gluten is consumed, the immune system responds by producing antibodies that attack the lining of the small intestine, specifically targeting the villi—small, finger-like projections that absorb nutrients from food. This immune response leads to inflammation and damage to the villi, which can result in nutrient deficiencies, digestive issues, and a wide range of symptoms. Unlike food allergies, which involve an immediate immune reaction, celiac disease involves a more complex immune response that causes chronic damage over time.