Celiac disease
Celiac disease is one of the autoimmune disorders in which the immune system attacks the cells of the body by mistake in the small intestine. The abnormal reaction of immune system happens when a person tries to eat foods that comprise of gluten, a type of protein that is present in barley, eye, and wheat. Autoimmune damage happening to the small intestine can result in the reduction of nutrient absorption including proteins thus leading to protein deficiency.