About 1% of the world's population suffers from celiac disease. This is an autoimmune disease in which the body mistakenly perceives gluten as a threat, which causes the immune system to respond by attacking the protein molecules. Unfortunately, this damages the intestinal wall, which can lead to nutritional deficiencies, digestive disorders, anemia, and an increased risk of developing dangerous diseases. People with celiac disease often experience severe stomach pain, diarrhea, constipation, skin rashes, bloating, weight loss, anemia, fatigue, and depression. Interestingly, some sufferers do not experience gastrointestinal problems but instead experience other symptoms such as fatigue, depression, and anemia. This symptomatology can be inherent in other ailments, so celiac disease is quite difficult to diagnose.