Avoidance of gluten containing foods has gained significant popularity in recent years. Whether it’s from a blog post, newspaper article, book from a celebrity doctor, a friend or colleague, or your own health care practitioner, most people have come across a discussion of a gluten-free diet at some point. With all this gluten fanfare, many are still left confused about whether there is truth to the health claims of gluten-related illnesses and gluten-free diets, and whether or not they should be changing what’s on their own dinner plate. This article aims to define the types of gluten-related illnesses reported in the scientific literature, their prevalence, and how they are clinically evaluated. While gluten containing foods are not bad for everyone, from our clinical and research perspective, the discussed gluten-related illnesses are relatively common and contribute significantly to chronic disease, and a gluten-free diet in these circumstances is indicated.
Celiac disease is an autoimmune disorder caused by eating gluten, a protein found in wheat, barley, rye, as well as ancient varieties of wheat such as spelt and kamut, in genetically susceptible individuals. The immune reaction caused by consuming gluten-containing foods produces significant inflammation, damaging the small intestine and leading to malabsorption of nutrients. Celiac disease affects about 1% of the population, making it one of the most common gastrointestinal diseases.(1) Many patients remain undiagnosed, especially those with atypical signs and symptoms of celiac disease.
Celiac disease has been termed a ‘clinical chameleon,’ because it can present in patients in many different forms.(2) The classical signs and symptoms of celiac disease include chronic or recurrent diarrhea, abdominal distension, weight loss, and abdominal pain. In children, malabsorption from celiac disease commonly affects proper growth and development. However, some individuals do not experience such classical signs and symptoms, and may instead have dental enamel defects, loss of bone density (osteopenia or osteoporosis), anemia, chronic fatigue, joint pain (arthritis), numbness and tingling of extremities (peripheral neuropathy), an itchy blistery skin rash called dermatitis herpetiformis, inflammation of the liver (hepatitis), infertility and recurrent pregnancy loss, or additional autoimmune disorders (such as type 1 diabetes and autoimmune thyroid disease).(3) While celiac disease was previously believed to be a disease of childhood, it is now understood that celiac disease can develop at any age.
In patients with symptoms of celiac disease and/or with risk factors such as a first-degree relative with the disease, laboratory screening for celiac disease is offered.(4) Standard laboratory testing to screen for celiac disease in Canada includes blood testing for immuoglobulin A (IgA) anti-tissue transglutaminase (TTG) antibody, and total IgA antibody levels.(1) Total IgA antibody levels are tested to rule out selective IgA deficiency and to avoid false-negative test results.
If screening tests come back positive for celiac disease, a small intestinal biopsy is then performed by a gastroenterologist to definitively diagnose the condition.(1) If a patient initiates a gluten-free diet before screening tests or intestinal biopsy are completed, false-negative test results can occur. For this reason, initiating a gluten-free diet prior to diagnosis is not recommended. In those who have already started a gluten-free diet, baseline antibody screening, a gluten-challenge diet prior to antibody screening, and/or genetic testing (for HLA DQ2 or HLA DQ8) may be recommended.(4)
A wheat allergy is an immediate and sometimes life-threatening immune reaction. Like most food allergies, signs and symptoms include breathing difficulties, skin eruptions such as hives, digestive problems and even anaphylaxis. Wheat allergy most commonly occurs in childhood, but can occur in adulthood with occupational exposure. It is reported that wheat allergy occurs in 0.4 percent of children in the United States.(5) Bloodwork that measures IgE antibodies or skin prick tests are used to diagnose this condition.
Non-Celiac Gluten Sensitivity:
Non-celiac gluten sensitivity (also known as gluten sensitivity) is a term used to describe gluten reactions that do not fit within the categories of celiac disease or wheat allergy. Individuals with gluten sensitivity have adverse symptoms after eating gluten containing foods, which resolve when these foods are removed from the diet. Common symptoms reported include digestive disturbances (abdominal pain, bloating, diarrhea and/or constipation, nausea, gastrointestinal reflux, canker sores), skin rashes, fatigue, brain fog, headaches, mood issues such as anxiety or depression, autoimmune disease, neuralgias, and fibromyalgia-like joint and muscle pain.(6) Other clinical characteristics include ADHD, autism, epilepsy and seizure disorders, gluten ataxia, and schizophrenia.(7)
While the prevalence of non-celiac gluten sensitivity is currently unknown, it is estimated to be more common than Celiac disease. A study conducted at the University of Maryland found that 347 out of 5896 patients evaluated met the diagnostic criteria for non-celiac gluten sensitivity, suggesting a prevalence of nearly 6%.(8)
Non-celiac gluten sensitivity is theorized to be a delayed immune reaction where the body produces IgG and/or IgA antibodies to gluten and its peptide gliadin.(9) Other researchers have proposed that gluten may not be the culprit and that individuals experiencing non-celiac gluten sensitivity may have a FODMAP (Fermentable, Oligo-, Di-, Mono-saccharides and Polyols) intolerance, and are unable to digest the complex carbohydrates (fructans) in grains such as wheat, rye, and barley.(10) In cases of FODMAP intolerance, individuals can often tolerate traditionally fermented grain products such as sourdough bread. While a FODMAP intolerance could explain the gastrointestinal symptoms that occur for many of these patients, it does not account for the systemic symptoms that often occur with this condition. Unlike celiac disease, these immune reactions do not cause atrophy of the small intestinal cells, but rather cause nonspecific inflammation in the gut, skin, joints, brain and nervous system.
The main reason why gluten sensitivity has been scrutinized is because researchers have not been able to define clear biomarkers (ie. lab tests) to diagnose this condition. For instance, IgG gliadin antibodies have been found to be elevated in 56% of patients with reported gluten sensitivity, and IgA gliadin antibodies have only been found to be elevated in 7% of patients with gluten sensitivity.(9) This type of testing leads to false negatives, and as a result some researchers suggest diagnosis of gluten sensitivity should be made by an elimination and challenge diet of gluten containing foods, after celiac disease and wheat allergy have been ruled out.(11)
New Insights on Gluten Sensitivity Testing:
One potential problem with the accuracy of gluten sensitivity testing is that gluten is made up of multiple proteins and peptides, and most modern day gluten sensitivity testing only includes antibodies (IgG and IgA) against one subtype of gliadin (alpha-gliadin).(12) Cyrex Laboratories have developed a gluten reactivity panel that includes multiple gluten proteins, peptides, and their subtypes which may help to improve accuracy and decrease false negative results. At Juniper Family Health, we provide comprehensive assessment of gluten intolerances, which may include Cyrex Lab’s gluten sensitivity panel, traditional celiac disease and wheat allergy testing, and elimination-challenge diets. While gluten doesn't cause health concerns in everyone, for a portion of the population it can contribute to chronic disease, and our goal is to uncover whether a gluten reaction is at play in this patient population.
In health and happiness,
Dr. Carla Cashin ND & Dr. Meghan van Drimmelen ND
(1) Rashidi, M. “Serologic testing in Celiac disease” Canadian Family Physician 62; 1 2016.
(2) Fasano, A. “Celiac disease - how to handle a clinical chameleon” N Engl J Med 348; 25 2003.
(3) Schuppan, D et al. “Pathogenesis, epidemiology, and clinical manifestations of celiac disease in adults” UpToDate 2016
(4) Kelly, C. “Diagnosis of celiac disease in adults” UpToDate 2016
(5) Jarvinen-Seppo, Kirsi. “Grain allergy: Clinical features, diagnosis, and management” UpToDate 2016
(6) Volta, U. et al. “An Italian perspective multi-center survey on patients suspected of having non-celiac gluten sensitivity.” BMC Med 12: 85 2014
(7) Jackson, J. et al. “Neurologic and psychiatric manifestations of celiac disease and gluten sensitivity” Psychiatr Q. 83: 1 2012
(8) Sapone, A. et al. “Non-Celiac Gluten Sensitivity: Where are we now in 2015?” Practical Gastroenterology June 2015.
(9) Volta, U. “Serological tests in gluten sensitivity (nonceliac gluten intolerance)” Journal of Clinical Gastroenterology 46: 8 2012.
(10) Hill, Ivor. “Epidemiology, pathogenesis, and clinical manifestations of celiac disease in children” UpToDate 2015.
(11) Catassi, C. et al. “Diagnosis of non-celiac gluten sensitivity (NCGS): The Salemo Experts' Criteria” Nutrients 7: 6 2015.
(12) Cyrex Labs Clinical Application Guide. Array 3 - Antibody Wheat/Gluten Proteome Reactivity & Autoimmunity. 2012