Celiac disease is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages starting in infancy. Symptoms include chronic diarrhea, failure to thrive, and fatigue. Increasingly, diagnoses are being made in asymptomatic persons as a result of increased screening. Serological blood tests are the first-line test to make the diagnosis. Antibody blood tests are highly specific and sensitive. Historically, celiac disease was thought to be rare, but the diagnosis has dramatically increased in the last 20 years.
The condition is thought to affect almost 1% of Americans. Celiac disease is caused by antibodies that react to an enzyme that modifies the gluten found in wheat and similar proteins found in barley and rye. Gluten is supposed to be broken down in the gut into amino acids, but in celiac disease, the gluten is absorbed into the intestinal wall, probably due to a failure of the barrier function in the intestine, called membrane leaking.
Humans first started to cultivate gluten grains beginning in the Neolithic era, about 10,000 years ago, so gluten ingestion is not part of a Paleolithic diet. People of African, Japanese and Chinese descent are rarely diagnosed with celiac disease, probably reflecting their reduced genetic risk. Population studies indicate that a large proportion of people with celiac disease are undiagnosed; due to the fact that many doctors are unfamiliar with how common the condition is. Celiac disease is more prevalent in women than in men.
The characteristic diarrhea stool is pale, voluminous and smells very bad. Abdominal pain, bloating and cramping are common. As the bowel becomes more damaged, a degree of milk intolerance may develop. Frequently, the symptoms are ascribed to irritable bowel syndrome, only later to be recognized as celiac disease. Subclinical disease is very common.
In 2004, Professor Martin Hewison of the University of Birmingham in England, one of the giants of vitamin D research, predicted that vitamin D was involved in the barrier functions of the body. That is, it helped keep toxins, foreign proteins, bacteria, fungi and viruses from penetrating the membranes of the lungs, skin, urinary, and/or GI tract.
As celiac disease involves a failure of the barrier function, one would expect vitamin D deficiency to be common in people with celiac disease, but that has not always been shown.
However, in a more recent study we blogged on last week, of 530 adult patients with celiac disease, 25% had levels less than 20 ng/ml, 34% had levels between 20 and 30 ng/ml and 41% had levels greater than 30 ng/ml.
In the above study, among celiac disease patients with an autoimmune disorder, vitamin D deficiency was not more common compared to celiac disease patients without an autoimmune disorder. Vitamin D deficiency was more common in celiac disease patients who presented with either anemia or psoriasis.
Celiac disease cannot be cured. However, your symptoms will go away if you follow a gluten-free diet. Do not eat foods, beverages, or medications that contain wheat, barley, rye, and possibly oats. Certainly, as an autoimmune disorder, celiac disease should be more likely among the vitamin D deficient. It is unclear if supplemental vitamin D will help celiac disease, and, from what we know now, a gluten free diet is the mainstay of treatment.