Diagnosing Gluten Intolerance: Not so Simple!

Gluten intolerance, also known as celiac disease, is a digestive disease that can cause severe damage to the small intestine. When a person with gluten intolerance eats even a small amount of gluten, a group of proteins found in wheat, rye, and barley, it triggers an immune response in the small intestine. This immune response attacks and damages the intestinal walls. Eventually, damage to the small intestines can make the body unable to absorb nutrients, leading to other complications such as malnutrition, vitamin and mineral deficiencies, and decreased bone density. The bad news is that there is no “cure” for gluten intolerance; but the good news is that it can be managed safely and effectively by eliminating gluten from the diet.

Why Diagnosis is Critical

Identifying and treating gluten intolerance is critical because without treatment gluten intolerance can lead to life-threatening complications, including:

· Malnutrition – Damage to the small intestine prevent proper absorption of nutrients, which can lead to nutrient deficiencies, anemia, weight loss, delayed development in children, stunted growth, and fertility problems.

· Decreased bone density – The damaged intestine cannot absorb sufficient calcium and vitamin D, which can result in osteomalacia (rickets) or osteoporosis.

· Lactose Intolerance and food allergies – The damaged intestine is more sensitive to irritation by food substance. Irritation and inflammation may also lead to a condition called ‘leaky gut’, a major cause of allergies..

· Cancer – Gluten intolerance can increase a person’s chance of developing several types of cancer when exposure to gluten continues.

· Neurological complications. The malabsorption of nutrients associated with gluten intolerance can eventually cause damage to the nervous system.

Gluten intolerance is also associated with a number of other conditions, including iron deficiency anemia, Type I diabetes, liver disease, Down’s syndrome, Turner’s syndrome, autoimmune thyroid disease, reproductive disorders, and other autoimmune diseases.

Causes of Gluten Intolerance

Gluten intolerance is a disease caused by the interplay of many different factors. One factor is a person’s genetic makeup: close relatives of people with gluten intolerance are about ten times more likely to be affected. However, even a person who is genetically predisposed to develop gluten intolerance might not develop the disease when exposed to gluten. How and why a person becomes gluten intolerant is not completely understood. Some people develop the disease as children, some as adults. In some individuals, onset seems to be triggered by a stressful event, severe illness, or injury. Some scientists think that giving infants cereals before 3 months might increase the risk of developing gluten intolerance.

Prevalence of Gluten Intolerance

Until recently, doctors believed gluten intolerance was a rare childhood disorder. Now, experts believe that gluten intolerance is under-diagnosed because it can be difficult to identify. Not everyone with the disease develops obvious symptoms and not everyone has the same symptoms. The most common symptoms – abdominal pain, diarrhea, and bloating – can indicate other conditions, further complicating diagnosis. New evidence suggests that formally diagnosed gluten intolerance (also called Celiac Disease or Coeliac Disease) affects 1-2% of the world’s population – about 3 million people in the United States, about 3 million in Europe, and about 200,000 in Australia. But some experts believe that around 1 in 7 people are gluten-sensitive or gluten-intolerant, though they do not test positive on standards tests for Celiac Disease. Experience suggests that this is likely to be a more realistic estimate.

A Tricky Disease to Diagnose

Gluten intolerance causes characteristic changes in the small intestine. The normal small intestine is lined with tiny, finger-like projections called villi, which are responsible for absorbing nutrients from food. In a person with gluten intolerance, the body’s immune reaction to gluten damages these villi. In some cases, the villi completely disappear. Without them, the damaged, inflamed small intestine is unable to absorb vitamins, minerals, and other nutrients the body needs.

This damage can cause a wide spectrum of symptoms that make the disease extremely difficult to identify and diagnose. In addition, many of the symptoms mimic those caused by other digestive disorders, making a correct diagnosis even more difficult. Some people develop intestinal symptoms, which can include cramping, abdominal pain, diarrhea, constipation, and bloating. Others don’t exhibit clear abdominal symptoms; instead, they exhibit secondary symptoms caused by their bodies’ inability to absorb nutrients, such as short stature in children, dental enamel problems, delayed puberty, iron-deficiency anemia, or osteoporosis. Still others exhibit symptoms seemingly unrelated to digestion or nutrition, such as a blistering skin rash, joint pain, irritability, depression, mouth sores, or tingling legs and feet.

Conventional Tests for Gluten Intolerance

Until recently, gluten intolerance was only rarely diagnosed. Doctors believed it to be a rare disorder, so were less likely to test a patient for this disease. Highly specific blood tests now make it easier for physicians to identify those at risk for gluten intolerance, even when they have only mild symptoms or no symptoms at all. Diagnosis of gluten intolerance is therefore multi-step process. It may begin when a doctor determines that the patient’s symptoms might indicate gluten intolerance, or with the patient’s own suspicions that symptoms are related to certain foods he or she is eating. In conventional medicine, this may lead directly to blood tests.

Usually, the doctor will instruct the patient to continue to eat foods containing gluten throughout the testing process, because the diagnostic tests lose their value once the patient stops eating gluten. If the patient is gluten intolerant, his intestines will begin to heal as soon as gluten is removed from his diet—diminishing or eliminating the intestinal damage and other indications that the diagnostic tests are designed to find. If the patient began a gluten-free diet before medical evaluation, he may be instructed to first undergo a “gluten challenge,” in which he adds gluten back into the diet for a period prior to testing. The problem with this approach is that the gluten challenge can cause unpleasant or even dangerous symptoms to recur, so not all patients opt for this route.

Otherwise, the first diagnostic test for gluten intolerance is a blood test. People who are gluten intolerant produce higher than normal levels of several antibodies, which are small substances produced by the body to help rid itself of foreign materials. When the body reacts to gluten, it causes an increased production of several different antibodies. Highly sensitive and specific tests can identify these antibodies in the patient’s blood. A positive test result provides a strong indication that the person might be gluten intolerant. One problem is that blood tests usually only test for certain antibodies that are recognized as relating to the disorder, but these antibodies are not involved in all food allergies.

A positive blood test result is still not generally considered enough for a firm diagnosis of gluten intolerance. The only definitive test for gluten intolerance is widely believed to be a biopsy. To obtain biopsy samples, the physician inserts a small, flexible tube called an endoscope through the mouth and into the small intestines, where he takes several samples of tissue from the intestinal walls. An expert will examine these samples under a microscope, looking for the characteristic damage caused by gluten intolerance. Several samples are required because the damage to the intestinal wall is often patchy. Even though one sample might appear normal other areas of the intestinal wall might display damage.

If a patient has a positive blood test and positive biopsy results, he or she will then start a gluten-free diet (elimination diet). If this diet causes symptoms to improve, then a definite diagnosis of gluten intolerance can finally be made. Sometimes, a patient will have symptoms suggesting gluten intolerance but a negative blood test or negative biopsy, leading to an inconclusive diagnosis. In this situation, genetic testing can help determine if the person is high- or low-risk for gluten intolerance, because certain genetic markers are strongly correlated with the disease.

When diagnosis is unclear, the patient and doctor consult to determine the best course of action. Choices include repeat blood tests, additional biopsies, or a gluten-free diet trial. The problem with this approach is that it focuses on several indicators, such as specific antibodies, that are not present in a great number of gluten intolerances or other allergies. Therefore, even the though gluten is clearly causing problems, gluten intolerance is not diagnosed. The doctor may attribute the symptoms to another disorder altogether, and the intolerance goes untreated. The patient may be left to her own devices for resolving the problem by experimentation with different foods or over-the-counter remedies to relieve digestive symptoms, not realizing that gluten intolerance is causing more damage inside the body.

An Alternative Approach to Diagnosing Gluten Intolerance

It is likely that many people with gluten intolerance fail all the conventional tests, but improve on a gluten-free diet. While an ‘elimination test’ (where gluten is removed from the diet completely) may not be considered sufficient basis for diagnosing gluten intolerance, it is an important indicator that gluten is a significant, if not the key factor in their symptoms, and a crucial part of the diagnostic process.

In integrative and alternative medicine, diagnosis of hard-to-pinpoint disorders like allergy and gluten intolerance are often approached from several directions, including patient history (including family history) of symptoms, illnesses and allergies, investigation of symptoms, anecdotal information (what the patient tells you about his or her experience with certain foods and symptoms), and non-invasive tests such as the elimination diet. More conventional testing procedures may or may not be part of this process, and in the case of children, are usually not recommended, as they can be very distressing.

If the practitioner also decides that a ‘challenge test’ (where gluten is re-introduced into the diet) should be part of the process, it should be done under practitioner supervision and in an environment where emergency treatment can be readily provided. This is important even if the patient does not usually experience severe reactions when eating gluten-containing foods because anaphylactic reactions (potentially fatal severe reactions to substances) can occur at any time. Another option is a rotation diet, where the person is exposed to gluten-containing foods only once every 4-6 days, giving the body time to clear of gluten and past reactions to it. This can help reduce the severity of reactions, while allowing gluten to be pinpointed as the offending substance.

Clearly, the diagnosis of gluten intolerance is essential. The more patients and physicians are aware of this disorder, the more cases can be identified and treated. Treatment almost always results in complete remission of the disease’s symptoms, and can prevent the development of other chronic diseases and disorders.

For articles on related topics, go to




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