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  • Scott Adams

    What is Celiac Disease and the Gluten-Free Diet?

    Scott Adams
    Reviewed and edited by a celiac disease expert.

      Symptoms of celiac disease can range from the classic features, such as diarrhea, upset stomach, bloating, gas, weight loss, and malnutrition, to no symptoms at all, and everything in between.

    Image: CC—Ed Uthman
    Caption: Image: CC—Ed Uthman

    Celiac disease is an autoimmune condition that affects around 1.4% of the population (91.2 million people worldwide, and 3.9 million in the U.S.A.). People with celiac disease suffer an autoimmune reaction when they consume wheat, rye or barley. The immune reaction is triggered by certain proteins in the wheat, rye, or barley, and, left untreated, causes damage to the small, finger-like structures, called villi, that line the gut. The damage occurs as shortening and villous flattening in the lamina propria and crypt regions of the intestines. The damage to these villi then leads to numerous other issues that commonly plague people with untreated celiac disease, including poor nutritional uptake, fatigue, and myriad other problems.

    Celiac disease mostly affects people of Northern European descent, but recent studies show that it also affects large numbers of people in Italy, China, Iran, India, and numerous other places thought to have few or no cases.

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    Celiac disease is most often uncovered because people experience symptoms that lead them to get tests for antibodies to gluten. If these tests are positive, then the people usually get biopsy confirmation of their celiac disease. Once they adopt a gluten-free diet, they usually see gut healing, and major improvements in their symptoms. 

    Symptoms of celiac disease can range from the classic features, such as diarrhea, upset stomach, bloating, gas, weight loss, and malnutrition, among others.

    Celiac disease can often less obvious symptoms, such fatigue, vitamin and nutrient deficiencies, anemia, to name a few. Often, these symptoms are regarded as less obvious because they are not gastrointestinal in nature. You got that right, it is not uncommon for people with celiac disease to have few or no gastrointestinal symptoms. That makes spotting and connecting these seemingly unrelated and unclear celiac symptoms so important.

    Currently, most people diagnosed with celiac disease do not show symptoms, but are diagnosed on the basis of referral for elevated risk factors. 

    Gluten intolerance is a generic term for people who have some sort of sensitivity to gluten. These people may or may not have celiac disease. Researchers generally agree that there is a condition called non-celiac gluten sensitivity. That term has largely replaced the term gluten-intolerance. What’s the difference between celiac disease and non-celiac gluten-sensitivity? 

    Gluten triggers symptoms and immune reactions in people with celiac disease. Gluten can also trigger symptoms in some people with NCGS, but the similarities largely end there.

    There are four main differences between celiac disease and non-celiac gluten sensitivity:

    1. No Hereditary Link in NCGS
      Researchers know for certain that genetic heredity plays a major role in celiac disease. If a first-degree relative has celiac disease, then you have a statistically higher risk of carrying genetic markers DQ2 and/or DQ8, and of developing celiac disease yourself. NCGS is not known to be hereditary. Some research has shown certain genetic associations, such as some NCGS patients, but there is no proof that NCGS is hereditary.
    2. No Connection with Celiac-related Disorders
      Unlike celiac disease, NCGS is so far not associated with malabsorption, nutritional deficiencies, or a higher risk of autoimmune disorders or intestinal malignancies.
    3. No Immunological or Serological Markers
      People with celiac disease nearly always test positive for antibodies to gluten proteins. Researchers have, as yet, identified no such antobodies or serologic markers for NCGS. That means that, unlike with celiac disease, there are no telltale screening tests that can point to NCGS.
    4. Absence of Celiac Disease or Wheat Allergy
      Doctors diagnose NCGS only by excluding both celiac disease, an IgE-mediated allergy to wheat, and by the noting ongoing adverse symptoms associated with gluten consumption.

    IBS and IBD are usually diagnosed in part by ruling out celiac disease. Many patients with irritable bowel syndrome are sensitive to gluten. Many experience celiac disease-like symptoms in reaction to wheat. However, patients with IBS generally show no gut damage, and do not test positive for antibodies to gliadin and other proteins as do people with celiac disease. Some IBS patients also suffer from NCGS.

    To add more confusion, many cases of IBS are, in fact, celiac disease in disguise.

    That said, people with IBS generally react to more than just wheat. People with NCGS generally react to wheat and not to other things, but that’s not always the case. Doctors generally try to rule out celiac disease before making a diagnosis of IBS or NCGS. 

    Crohn’s Disease and celiac disease share many common symptoms, though causes are different.  In Crohn’s disease, the immune system can cause disruption anywhere along the gastrointestinal tract, and a diagnosis of Crohn’s disease typically requires more diagnostic testing than does a celiac diagnosis.  

    Crohn’s treatment consists of changes to diet and possible surgery.  Up to 10% of Crohn's patients can have both of conditions, which suggests a genetic connection, and researchers continue to examine that connection.

    Diagnosis of celiac disease can be difficult

    Perhaps because celiac disease presents clinically in such a variety of ways, proper diagnosis often takes years. A positive serological test for antibodies against tissue transglutaminase is considered a very strong diagnostic indicator, and a duodenal biopsy revealing villous atrophy is still considered by many to be the diagnostic gold standard. 

    But this idea is being questioned; some think the biopsy is unnecessary in the face of clear serological tests and obvious symptoms. Also, researchers are developing accurate and reliable ways to test for celiac disease even when patients are already avoiding wheat. In the past, patients needed to be consuming wheat to get an accurate test result. 

    Currently, testing and biopsy still form the cornerstone of celiac diagnosis.

    There are several serologic (blood) tests available that screen for celiac disease antibodies, but the most commonly used is called a tTG-IgA test. If blood test results suggest celiac disease, your physician will recommend a biopsy of your small intestine to confirm the diagnosis.

    Testing is fairly simple and involves screening the patients blood for antigliadin (AGA) and endomysium antibodies (EmA), and/or doing a biopsy on the areas of the intestines mentioned above, which is still the standard for a formal diagnosis. Also, it is now possible to test people for celiac disease without making them concume wheat products.

    Until recently, biopsy confirmation of a positive gluten antibody test was the gold standard for celiac diagnosis. It still is, but things are changing fairly quickly. Children can now be accurately diagnosed for celiac disease without biopsy. Diagnosis based on level of TGA-IgA 10-fold or more the ULN, a positive result from the EMA tests in a second blood sample, and the presence of at least 1 symptom could avoid risks and costs of endoscopy for more than half the children with celiac disease worldwide.

    Currently the only effective, medically approved treatment for celiac disease is a strict gluten-free diet. Following a gluten-free diet relieves symptoms, promotes gut healing, and prevents nearly all celiac-related complications. 

    A gluten-free diet means avoiding all products that contain wheat, rye and barley, or any of their derivatives. This is a difficult task as there are many hidden sources of gluten found in the ingredients of many processed foods. Still, with effort, most people with celiac disease manage to make the transition. The vast majority of celiac disease patients who follow a gluten-free diet see symptom relief and experience gut healing within two years.

    For these reasons, a gluten-free diet remains the only effective, medically proven treatment for celiac disease.

    There is currently no enzyme or vaccine that can replace a gluten-free diet for people with celiac disease.

    There are enzyme supplements currently available, such as AN-PEP, Latiglutetenase, GluteGuard, and KumaMax, which may help to mitigate accidental gluten ingestion by celiacs. KumaMax, has been shown to survive the stomach, and to break down gluten in the small intestine. Latiglutenase, formerly known as ALV003, is an enzyme therapy designed to be taken with meals. GluteGuard has been shown to significantly protect celiac patients from the serious symptoms they would normally experience after gluten ingestion. There are other enzymes, including those based on papaya enzymes.

    Additionally, there are many celiac disease drugs, enzymes, and therapies in various stages of development by pharmaceutical companies, including at least one vaccine that has received financial backing. At some point in the not too distant future there will likely be new treatments available for those who seek an alternative to a lifelong gluten-free diet. 

    For now though, there are no products on the market that can take the place of a gluten-free diet. Any enzyme or other treatment for celiac disease is intended to be used in conjunction with a gluten-free diet, not as a replacement.

    The most common disorders associated with celiac disease are thyroid disease and Type 1 Diabetes, however, celiac disease is associated with many other conditions, including but not limited to the following autoimmune conditions:

    • Type 1 Diabetes Mellitus: 2.4-16.4%
    • Multiple Sclerosis (MS): 11%
    • Hashimoto’s thyroiditis: 4-6%
    • Autoimmune hepatitis: 6-15%
    • Addison disease: 6%
    • Arthritis: 1.5-7.5%
    • Sjögren’s syndrome: 2-15%
    • Idiopathic dilated cardiomyopathy: 5.7%
    • IgA Nephropathy (Berger’s Disease): 3.6%

    Other celiac co-morditities include:

    • Crohn’s Disease; Inflammatory Bowel Disease
    • Chronic Pancreatitis
    • Down Syndrome
    • Irritable Bowel Syndrome (IBS)
    • Lupus
    • Multiple Sclerosis
    • Primary Biliary Cirrhosis
    • Primary Sclerosing Cholangitis
    • Psoriasis
    • Rheumatoid Arthritis
    • Scleroderma
    • Turner Syndrome
    • Ulcerative Colitis; Inflammatory Bowel Disease
    • Williams Syndrome


    • Non-Hodgkin lymphoma (intestinal and extra-intestinal, T- and B-cell types)
    • Small intestinal adenocarcinoma
    • Esophageal carcinoma
    • Papillary thyroid cancer
    • Melanoma


    Edited by Scott Adams


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    Nobody ever mentions the blood group diet. Have been following it for about 19 months now and not only lost weight, but also felt better and more energetic. Also cut out gluten, the oats, barley and rye which made me felt bad. Once you follow the blood group diet, AS A GUIDELINE, your body becomes normal and then you start noticing what causes problems. Anemia might indicate you are A blood group.

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    I've been celiac diagnosed for 3 years. No gluten eating ever and no restaurant eating--not safe anytime. I get weak, sick nausea, fee like the flu. I'm working on getting to work and still seriously worried can not 100% control condition. It should be healed by now and my doctor considers it healed. Well, I'm sick from something. Just need more deep information on this if available.

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    Hey, yes you can absolutely be putting on weight. My son was a large boy and as he started eating solid foods he ate large amounts. It was just amazing how much that boy could put away. He wasn't obese but you'd never think he was malnourished. And then once he was off the bottles and completely on real food, the constant diarhea of undigested food started and his weight gain slowed. Soon, his tummy hurt too much to eat a lot and it finally occurred to me one day to try taking him off wheat. The change was enormous: within 24 hours I had a healthy, happy little boy instead of a crazy, hyperactive whiny brat that kept waking up all night every night and barfing randomly at night sometimes.

    Wow this is teaching me so much. I'm actually becoming more and more afraid that I may have celiac disease. I went to a new doctor and he started asking me all these questions on digestion. What I eat, how I feel, when this junk started. I can hardly eat a fist sized amount of food a day now. In 2009 I weighed 200 ibs. In 2011 I weighed 228 lbs. Now I weight 165. I lost all that in 14 months, with no extra physical activity at all. If I eat anything before half my day is over I throw up. I have stomach ulcers and so I was told years ago to stay away from acidy foods and eat more bread and rice. It is easier on my stomach said the doctors. If my diagnosis is confirmed, this website will be my new favorite.

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    Nice article, but the first sentence threw me. It says that Gluten Intolerance and Celiac Disease are the same thing? I have always been told they are two separate things, so correct me if I am wrong. I am celiac (biopsy) and have no intolerance issues that I know of, which I understand is common. The few times I have accidentally had gluten I had no problems. I have been gluten free for one year.

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    Don't you think it's confusing for readers to say celiac disease is gluten intolerance? I do.

    I just realized this article is from 1996. While it has some good information, it is woefully out of date.

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    Excellent source of info... Does anyone with this illness suffer from severe depression?

    I am 83 years old and just this past Christmas season started having the loose bowl problems; I was very depressed with life in general. Anything that happened seemed to make me feel worse. After a couple of months I finally decided to see a doctor. She told me to stop eating dairy and she also arranged for me to see another doctor about the problem. It didn't clear up going dairy free. In the meantime someone mentioned celiac disease. I looked it up on several sites on the internet and was convinced that was my problem. So I gave

    up gluten and immediately started feeling better. Within just a few days I was much better,the depression was much better right away also. However, for about three weeks now it seems the gluten is appearing in spices,etc.,so that I have a reaction. I need to read labels 'all' the time now. I am thinking of going on the Paleo Diet, also known as the Caveman Diet. In other words if it wasn't around for the cavemen to eat then I shouldn't.

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    Ok I am sure I have this now. The medicine cannot seem to help level out my thyroid levels. With each blood test, it just seems to get worse. I'm going crazy between the nerve pain in my legs and no sleep or energy. Then add depression. Not good. The doctor, after asking him about it today, wanted me to try going gluten-free without testing first. But I heard it's better to be tested first because if you go gluten-free first, it can mess up later lab work. Has anyone else heard of this? Thank you so much, everyone

    Yes Tina,when I called the doctor to let her know that I had been going gluten free she said it would have been better to have had the test before I gave up gluten,because now I will have to eat gluten for 2 months before I can get the test.

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    Are you a new parent? If you are, you may be looking for safe and healthy foods to feed your baby. Parents should know the best for their babies. If this causes your concern, you may want to take the time to examine organic baby food.

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    Celiac disease and gluten intolerance are two different health issues. Celiac disease is an autoimmune disease of the small intestine. Even a tiny crumb of gluten can trigger the immune system to attack and damage the small intestine In this case, it is the immune system that causes intestinal inflammation. On the other hand, gluten intolerance is an inability of your intestines to properly digest gluten. The definition above is misleading and should be changed, particularly for the newly diagnosed who may not yet understand the implications of having a serious genetic autoimmune disease.

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    So not to sound dumb but u was diagnosedwith gluten entropy in 2014 after my poor daughter of multiple food allergies was born.Then I recently just started to try a Lil bit if gluten here again and I get rashes,diareha,and I also get swollen lips and numbNess in my hands and feet.So I'm back to going gluten-free yet is this diet for life?bc the gastro told me I didn't have celiac yet buy was on my way so confusing.I would like a diagnosis so at least we can test my daughters to see if they have as well bc they seem to get same symptoms :(

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    9 hours ago, diemertfgd@gmail.com said:

    So not to sound dumb but u was diagnosedwith gluten entropy in 2014 after my poor daughter of multiple food allergies was born.Then I recently just started to try a Lil bit if gluten here again and I get rashes,diareha,and I also get swollen lips and numbNess in my hands and feet.So I'm back to going gluten-free yet is this diet for life?bc the gastro told me I didn't have celiac yet buy was on my way so confusing.I would like a diagnosis so at least we can test my daughters to see if they have as well bc they seem to get same symptoms :(

    Where you tested for Celiac? You have to be eating gluten to get tested, 12 weeks at least half a slice of bread a day or a few crackers or some get by with a tsp of vital wheat germ/gluten. After the blood test a endoscope is needed with multiple biopsies and again at least 2 weeks of gluten consumption daily prior to this.
    The disease is genetic so if your and your children have this reaction bit of a sign. Numbness like peripheral nephropathy or gluten ataxia is associated in some with this disease like me. The rash, is it symmetrical? Some with this disease get something called dermatitis herpetiformis or DH for short. In the case of DH you might be lucky when the rash shows go have the doctor take biopsy punch NEXT to the lesions and have it checked for a diagnosis. https://celiac.org/celiac-disease/understanding-celiac-disease-2/dermatitis-herpetiformis/

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  • About Me

    Scott Adams was diagnosed with celiac disease in 1994, and, due to the nearly total lack of information available at that time, was forced to become an expert on the disease in order to recover. In 1995 he launched the site that later became Celiac.com to help as many people as possible with celiac disease get diagnosed so they can begin to live happy, healthy gluten-free lives.  He is co-author of the book Cereal Killers, and founder and publisher of the (formerly paper) newsletter Journal of Gluten Sensitivity. In 1998 he founded The Gluten-Free Mall which he sold in 2014. Celiac.com does not sell any products, and is 100% advertiser supported.

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