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.
When people with celiac disease eat gluten (a protein found in wheat, rye and barley), their body mounts an immune response that attacks the small intestine. These attacks lead to damage on the villi, small fingerlike projections that line the small intestine, that promote nutrient absorption.