What is celiac disease?
Celiac disease is an autoimmune condition where the intake of gluten
causes the body’s immune system to attack the healthy lining of the small
intestine.1 Celiac disease is also known as gluten-sensitive
enteropathy, celiac sprue, and nontropical sprue.2 Celiac disease is
a type of gluten-related disorder. Other gluten-related disorders include
non-celiac gluten sensitivity and wheat allergy.3
How common is celiac
disease?
Celiac
disease occurs mostly in Caucasians of European descent and is estimated to affect
approximately 0.5% to 1% of population worldwide.4,5 Celiac disease is
relatively rare among those of Chinese, Japanese, Korea, and African heritage.5
The disease can occur in people of any age and is 2
to 3 times more common in women than men. Celiac disease is hereditary and the
incidence (which is the number of newly diagnosed cases of a disease) is
approximately 5% to 10% in first-degree relatives of patients with celiac
disease.2,4,7
What is gluten? How does
it cause celiac disease?
Gluten is a protein that can be found in wheat, rye, or barley, as
well as the many foods made with these grains. Gluten can also be found in oats
that may be contaminated with wheat, rye, or barley during processing. Some
medications may also contain gluten.1, 2
Celiac disease occurs in individuals who have a sensitivity to
gluten due to their genetic makeup. The body’s immune system usually acts to
protect the body from disease and infections. However, in celiac disease, the
ingestion of gluten by susceptible individuals causes the body’s immune
response to abnormally produce antibodies and other substances that damage the cells
lining the small intestine, adversely affecting the small intestine’s role in
nutrient absorption from food.6
This increases the risk of nutritional deficiencies and other
complications such as fatigue, anemia (low red blood cell count), and
osteoporosis.1,2 In addition, celiac disease has been found to be
associated with a severe skin rash known as dermatitis herpetiformis and other
conditions such as diabetes mellitus type 1 and thyroiditis.1,4
What are the symptoms of
celiac disease?
The
presentation of celiac disease is wide-ranging and has been likened to “an
iceberg”, with a small group of individuals with classic disease who present
with symptoms of malabsorption, diarrhea, and weight loss; and a larger group
of individuals who may only display minor gastrointestinal symptoms and other nongastrointestinal-related
symptoms such as anemia, osteopenia, infertility, and neurological symptoms
(atypical celiac disease). Many individuals with celiac disease may experience
no symptoms at all (silent celiac disease).4,7
The
symptoms of celiac disease can include1,2,7,8:
§
Gastrointestinal symptoms (abdominal bloating, pain, gas, diarrhea)
§
Weight loss
§
Severe skin rash
§
Anemia
§
Joint and bone pain
§
Tingling and numbness in the fingers or legs
How is celiac disease
diagnosed?
Your
healthcare provider will first ask you about your symptoms and medical history.
Other diagnostic tests include the following:
§
Blood tests. Blood tests are done to check the level of specific
antibodies in your blood. In celiac disease, there are specific antibodies that
will be elevated. It is important to remain on a gluten-rich diet (or your
normal diet) when this blood test is performed. Otherwise, the antibody levels
may become undetectable after a gluten-free diet is started.1,2,7 Other blood tests may also be done to
evaluate for deficiencies in iron, folate, calcium, and vitamin D.
§
Small intestinal biopsy. A small intestinal biopsy is performed when an
individual tests positive for the specific antibodies in their blood test. A
small sample of tissue will be removed from the small intestines by means of a
small, flexible tube inserted through the mouth. The sample of tissue will then
be examined under the microscope to look for changes characteristic of celiac
disease in the small intestine tissue.1,2,7
How is celiac disease
treated?
Implementation of a gluten-free diet
Treatment
of celiac disease requires implementation of a gluten-free diet where products
containing wheat, barley, and rye are removed from the diet for life to avoid
exposure to dietary gluten.1,2 Approximately 70% of individuals
experience improvement in their symptoms within 2 weeks of starting a
gluten-free diet.9 The Table below lists examples of gluten-free
foods.10
Table. List of gluten-free
foods.10
Grains, flours and other
starch-containing food
|
Other foods
|
Beans/ bean flours
Buckwheat
Corn/ corn flours
Flaxseed
Legumes
Millet
Nuts/ nut flours
|
Potatoes, potato starch/ flour
Quinoa
Rice
Soy
Tapioca/ tapioca starch
Wild rice
|
Fruits
Vegetables
Meat and poultry
Fish and seafood
Dairy products
|
|
|
|
The
complete elimination of gluten from the diet may be difficult as many processed
foods use wheat in their manufacture. Thus, working with a dietitian can be
beneficial to help find out about places to purchase gluten-free foods, cooking
methods, and lifestyle resources to maintain a balanced, gluten-free diet. Individuals
are encouraged to read labels on processed foods with care to determine if the
food product contains wheat, barley, or rye.7
Although
there is evidence that celiac patients can tolerate moderate quantities of oats
(about 50 g per day), oats are frequently contaminated with wheat during their
manufacture.6 Thus, it
is recommended for patients newly diagnosed with celiac disease to avoid oats
until symptoms resolve through a gluten-free diet. After symptoms have been
controlled, up to 2 oz of oats from a reliable, uncontaminated source can be
eaten daily and continued if symptoms do not return.2
Distilled
alcoholic beverages such as wines are gluten-free unless gluten-containing flavorings
are added after production. It is important to note that malt beverages such as
beer, lager, ale, and stouts are not considered gluten-free and should be
avoided.2,7
Avoidance of dairy products
Some
patients with untreated celiac disease may find that they are unable to tolerate
dairy products when they are first diagnosed with the disease.12 The lactase enzyme, which is
required to break down lactose in dairy products, is produced by cells that
line the small intestine. In celiac disease, the production of the lactase
enzyme is decreased due to the damage to the lining of the small intestine, resulting
in lactose deficiency.2 Patients may choose lactose-reduced or lactose-free products
if their symptoms are worsened by dairy products. Dairy products can be reintroduced
after 3 to 6 months of a gluten-free diet when the lining of small intestine
heals.
Dietary supplements
Patients
with vitamin malabsorption may also receive a multivitamin preparation and
appropriate supplements to correct nutritional deficiencies, including iron,
folate, B vitamins, copper, and zinc. Other dietary supplements may include
calcium and vitamin D for those individuals with hypocalcemia (low calcium) and
osteopenic bone disease to prevent further bone loss.2
Gluten in medications
Inactive
ingredients used as binders for medication pills or tablets may sometimes
include starches or starch derivatives that contain gluten. In other cases,
medications may come into contact with gluten during the manufacturing process.
It is thus important for patients with celiac disease to be vigilant in
checking the content of their medications with their pharmacist prior to taking
them.11 A helpful online resource is the website: http://www.glutenfreedrugs.com/,
which is maintained by a clinical pharmacist and contains a list of medications
that are gluten-free.12
Complications of celiac
disease
It
is important for patients with celiac disease to maintain a gluten-free diet
for life to avoid complications of the disease.2 Complications of
celiac disease can include13:
§
Malnutrition
§
Nonresponsive celiac disease, where patients continue to experience
symptoms despite a gluten-free diet, commonly due to unintentional ingestion of
food contaminated with gluten.
§
Dermatitis herpetiformis, a skin condition where patient has very itchy
bumps and blisters that look similar to those caused by the herpes virus. These
bumps and blisters usually go away gradually after gluten is removed from the diet.
Where can I find more information?
§
Academy of Nutrition and Dietetics (formerly American Dietetic
Association) (www.eatright.org)
§
North American Society for the Study of Celiac Disease (www.nasscd.org)
References
1.
Green PH, Cellier C. Celiac disease. N
Engl J Med. 2007;357(17):1731-1743.
2.
Farrell RJ, Kelly CP. Celiac sprue.
N Engl J Med. 2002;346(3):180-188.
3.
Czaja-bulsa G. Non coeliac gluten sensitivity - A new disease with
gluten intolerance. [published ahead of print August 29, 2014] Clin
Nutr. pii: S0261-5614(14)00218-0. doi: 10.1016/j.clnu.2014.08.012.
4.
Binder HJ. Chapter 294. Disorders of Absorption. In: Longo DL, Fauci AS,
Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds. Harrison's Principles of
Internal Medicine, 18e. New York, NY: McGraw-Hill; 2012. http://accessmedicine.mhmedical.com/content.aspx?bookid=331&Sectionid=40727087.
Accessed November 21, 2014.
5.
Tack GJ, Verbeek WH, Schreurs MW, Mulder CJ. The spectrum of celiac
disease: epidemiology, clinical aspects and treatment. Nat Rev Gastroenterol Hepatol. 2010;7(4):204-213.
6.
Schuppan D. Current concepts of celiac disease pathogenesis. Gastroenterology. 2000;119(1):234-242.
7.
Schuppan D, Dieterich W Pathogenesis, epidemiology, and clinical
manifestations of celiac disease in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate; 2014.
www.uptodate.com. Accessed November 21, 2014.
8.
Chin RL, Sander HW, Brannagan TH, et al. Celiac neuropathy. Neurology. 2003;60(10):1581-1585.
9.
Pink IJ, Creamer B. Response to a gluten-free diet
of patients with the coeliac syndrome. Lancet.
1967;1(7485):300-304.
11. King AR. Gluten Content of
the Top 200 Medications: Follow-Up to the Influence of Gluten on a Patient's
Medication Choices. Hosp Pharm.
2013;48(9):736-743.
13. Kelly CP, Dennis M.
Patient information: Celiac disease in adults (Beyond the Basics). In: Post TW,
ed. UpToDate. Waltham, MA: UpToDate; 2014. www.uptodate.com. Accessed December
12, 2014.
Prepared
by:
Lim
Yi Jing, RPh
PharmD
Candidate, 2015
National
University of Singapore
