FAQ: Medical Managment & Understanding of Celiac Disease
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More detailed answers are available on www.celiacnow.org.
What happens when I eat gluten?
Currently, it is believed that proteins derived from the digestion of gluten, (the part of grains toxic to people with celiac disease) including gliadin, are able to pass into the wall of the intestine. Once inside the intestinal wall (in the submucosa), an enzyme known as tissue transglutaminase, or IgA-tTG, changes the shape of the small gliadin proteins. The modified gliadin is then processed by antigen presenting cells. These cells are designed to present many different kinds of substances to the immune cells. The immune system (the body's natural defense system that normally protects the body from infection) then decides what is harmful and what is not.
After processing by the antigen presenting cell, the gliadin in its new shape is able to activate the immune system through binding to T cells (immune cell type), causing inflammation and the release of chemicals that can affect the entire body. Only people that have the HLA-DQ2 or HLA-DQ8 genes have T cells that bind gluten proteins (mostly gliadin). The ability of these cells to bind to gluten-derived peptides is inherited. It seems to be the main reason why some people get celiac disease (CD) and others do not.
The small intestine is lined with finger-like projections called villi. The villi are needed to produce digestive enzymes and aid in the absorption of nutrients. When a patient with CD eats gluten, these villi become shorter or flattened, with less ability to make enzymes. The shorter villi decrease the surface area available to absorb nutrients. The overall result of eating gluten is decreased digestion and nutrient absorption. This can lead to malnutrition and symptoms such as diarrhea and fatigue (feeling tired).
Are the villi permanently damaged in celiac disease (CD)? If not, how long will they take to recover?
The villi are not permanently damaged in CD, but it may take years for the villi to fully recover in older people. The intestine is able to regenerate every three days, but the amount of time it takes for the villi to return to normal varies from person to person. In general, the intestine is expected to heal over a period of weeks to months on a gluten-free diet.
If a person with celiac disease (CD) does not follow the gluten-free diet (GFD) carefully, does it cause permanent damage?
Once CD is diagnosed, a life long GFD is the only available treatment. Continuous exposure to gluten in people with CD can lead to severe small intestinal damage (complete loss of villi). Untreated CD can also lead to malabsorption, bone loss, nutritional deficiencies, and a small but real risk of gastrointestinal cancers such as small intestinal lymphoma. This damage can be reversed or improved substantially in the majority of people who follow the GFD closely.
If a person with celiac disease (CD) follows the gluten–free diet (GFD) very carefully but the IgA-tTG level continues to rise, what can it mean? Could dairy or fructose affect the IgA-tTG blood level?
This is not an unusual complaint. Once CD is confirmed through biopsy and IgA-tTG testing, the IgA-tTG levels should trend down by half-fold in 3-6 months. Persistently high IgA-tTG means that the CD is not well controlled. The most common cause is accidental exposure to gluten. Meeting with a dietitian skilled in celiac disease is very important and useful.
Sometimes elevated IgA-tTg can be found in patients with small intestinal bacterial overgrowth. Common symptoms of SIBO include bloating, gas, indigestion and diarrhea. SIBO may be an alternative explanation to "latent"(dormant) or "potential" celiac disease for a positive IgA-tTG level in a patient with either a normal or only mildly abnormal small intestinal biopsy result.
A minority of patients with CD will have continued high IgA-tTG levels despite being on a strict GFD. This is called refractory celiac and is often treated with medication in addition to the GFD. Visit Non-Responsive Celiac Disease Level 2 under Medical Management on www.celiacnow.org. While diary and fructose could cause symptoms that mimic “uncontrolled celiac”, they do not typically cause elevation of the IgA-tTG.
Why does a small or large amount of gluten elicit the same response? Why is it not dose related?
Celiac disease (CD) is an autoimmune condition that leads to changes in the immune system in genetically predisposed people upon exposure to gluten. This condition causes intestinal inflammation and gastrointestinal symptoms.
Studies have looked at determining the safe levels of gluten exposure. The lowest amount of daily gluten that causes damage to the small intestinal mucosa over time (the gluten threshold) is 10 to 50 mg per day (a 25-g slice of wheat bread contains approximately 1.6 g of gluten). The Codex Alimentarius http://www.nejm.org/doi/full/10.1056/NEJMcp1113994 - ref35#ref35 regulation and the Food and Drug Administration both endorse a maximum gluten contamination of <20 ppm (parts per million) in a gluten-free product. Less than twenty ppm is considered a safe threshold even for patients who eat large amounts of wheat/gluten substitutes.
Once the amount of gluten intake crosses this threshold, the severity of gastrointestinal symptoms and intestinal damage is independent of the quantity of gluten intake. The chain of inflammatory events that are activated once the threshold is passed is independent of the amount of gluten. This phenomenon is not completely understood.
If each bottle of gluten-free beer is labeled 20 parts per million (ppm), and I drink 6 beers, have I then ingested 120ppm of gluten?
While this may seem reasonable, it is not correct as ppm are not additive in this way. If this was the case you could make the same argument for a bite of a food vs. a serving of that same food when obviously there will be different total amounts of gluten depending on how much you eat. 20 ppm was chosen based on what is both safe with easily achievable amounts of food and easily measurable. A food with 20ppm of gluten is about .002% gluten or 20mg/kg. Given the usual threshold of 50mg per day of gluten you need to eat ~2.5 kg or 5.5 pounds of that food in a day to be a problem. This would be equivalent to about 4 or 5 loaves of bread! It doesn’t matter what the food is as long as it has the same ppm rating.
What healthcare providers should I see?
Once diagnosed with celiac disease (CD), it is important to maintain life-long follow up with a doctor regarding your condition. This follow-up is especially important since there are several manifestations of CD that are not related to the gastrointestinal tract. Visit FAQ- Associated Conditions on www.celiacnow.org.
Specifically, you should see your primary care physician (PCP) for any initial problems you may have. Your PCP or another specialist may make or suspect the initial diagnosis of CD. However, a referral to a gastroenterologist skilled in the diagnosis and management of CD is usually needed to confirm the initial diagnosis and plan further management including:
- Counseling regarding the test results and screening of family members
- Evaluation for associated disorders
- Arranging for consultation(s) with a skilled celiac dietitian
- Initial education regarding dietary treatment of CD
- Evaluation for nutritional deficiencies
- Initiation of nutritional supplements, as needed
- Monitoring your response to the gluten-free diet
- Adjustment of diet, as well as nutritional supplements, according to clinical and immunologic response
The National Institutes of Health recommend the following 6 key elements in the management of individuals affected by celiac disease:
- Consultation with a skilled dietitian
- Education about the disease
- Lifelong adherence to a gluten-free diet
- Identification and treatment of nutritional deficiencies
- Access to an advocacy group
- Continuous long-term follow-up by a multidisciplinary team
If an associated disorder is discovered, such as thyroid disease, you may be referred to another specialized doctor for management of the problem. In the case of CD, an endocrinologist may be seen for thyroid problems, diabetes, or management of bone health. A social worker or clinical psychologist can often be a helpful referral to support the emotional and social adjustment to living with celiac disease.
The Celiac Center at Beth Israel Deaconess Medical Center has a listing of clinicians skilled in the management of celiac disease. These individuals will aid in the diagnosis of the disease if you or your doctor suspects CD and will also provide long-term specialized care for people already diagnosed with CD. Please visit Our Celiac Center Team on www.celiacnow.org home page. Also visit What to Expect from your Gastroenterologist’s Visit under Medical Management on celiacnow.org.
Revision Date: 3-18-16
Authors: Clinicians of the Celiac Center, Dharmesh H Kaswala MD, Javier Villafuerte MD, Rohini Vanga MD, with assistance from Annie Peer
Editors: Melinda Dennis, MS, RD, LDN and Daniel Leffler MD, MS, Rupa Mukherjee MD