The varieties of language you use in different areas of your life are known as speaking or writing styles. Some particularly specialized styles, such as those used in the courtroom, or poetry, or the operating room, are known as registers.
The United States National Institutes of Health recommends testing vitamin A levels in people with celiac disease at diagnosis. This is because vitamin A deficiency is common in celiac disease. Deficiency can result from incomplete digestion, absorption, or metabolism. Normal absorption of vitamin A first requires digestion, or releasing, from food protein in the stomach.
Celiac disease, also known as coeliac disease, is an autoimmune disorder that affects around 1 in 100 Americans. The disease is caused by gluten intolerance. Gliadin, a protein in wheat, causes the afflicted persons immune system to attack its own bowel tissue. This causes villous atrophy, or the erosion of the nutrient absorbing villi that line the small intestine. Other grains, like barley and rye, have similarly shaped proteins which can cause the same reaction in sensitive individuals. Celiac disease can cause irreversible damage. The issue seems to be genetic in cause and can be passed down through generations. Testing for celiac disease is done through blood tests and endoscopy. It is important for the afflicted person to continue eating gluten while they are tested for celiac disease.