What is celiac disease?
Celiac disease is an uncommon disease in which your immune system attacks the cells lining the small intestine. The reaction is provoked by gliadin, one of the proteins in gluten that is found in wheat and some other grains. The immune reaction results in inflammation and destruction of the intestinal lining cells. The destruction of the lining affects the ability of the lining to function normally, particularly in the absorption of food including macronutrients (fat, protein, and carbohydrates) and micronutrients (vitamins, and minerals). Thus, although some of the symptoms of celiac disease may be a result of the ongoing inflammation and destruction, most of the symptoms are the result of the malabsorption. The presence of celiac disease usually is suspected on the basis of symptoms, but the diagnosis is confirmed with a combination of blood tests and biopsy of the intestine. It is common in both men and women.
Macronutrients and celiac disease
Fat is the most commonly malabsorbed macronutrient. The reduction in fat absorption greatly reduces the intake of calories (as does the malabsorption of protein and carbohydrates although to a lesser degree), and that causes loss of weight. Malabsorbed fat within the distal intestine is digested by intestinal bacteria. The bacteria break down the fat into smaller compounds that cause the secretion of fluid into the intestine that can result in diarrhea. The abdominal bloating and/or gas (flatulence) that occurs in celiac disease may be due to the malabsorption of carbohydrates and the formation of gas from the carbohydrates by the intestinal bacteria. Malabsorption of dietary protein leads to a deficiency of proteins within the body that can result in muscle wasting and a low blood albumin (the most abundant protein in the blood) that results in swelling of the ankles (edema).
Micronutrients in celiac disease
The symptoms of deficiencies in micronutrients vary widely depending on the deficiency. Some of the more important deficiencies include iron deficiency which can lead to anemia and fatigue as well as vitamin K deficiency which can lead to abnormalities in blood clotting and excessive bruising or bleeding. Deficiencies of calcium, magnesium, vitamin B12, thiamine, pantothenic acid, and vitamin A can lead to neurological symptoms while deficiencies of calcium and vitamin D can lead to weakened bones and fractures.
Other disease associated with celiac disease
Celiac disease is associated with several other autoimmune diseases that may cause their own symptoms. These diseases include dermatitis herpetiformis, a type of skin rash, type 1 diabetes, and inflammation of the thyroid.
Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care
Patient information: Celiac disease in adults (Beyond the Basics).