Many individuals who experience symptoms from eating wheat often believe that gluten is the cause of their symptoms and reach for gluten-free products. However, before reaching for these products, it is important to get an accurate diagnosis. Diseases associated with wheat hypersensitivity may be mild with few long-term effects or can have more serious consequences.
There are three main diseases associated with wheat hypersensitivities – celiac disease, wheat allergy, and non-celiac wheat sensitivity. Depending on what type of wheat hypersensitivity you have, gluten-free products may only partly address your symptoms. It is also likely that by eliminating wheat and other gluten containing products, you may be unnecessarily restricting your diet. An accurate diagnosis can help manage and treat symptoms so as to prevent long-term and more serious effects.
Although both wheat allergy and celiac disease are immune disorders, celiac disease differs from wheat allergy in that it is an autoimmune disorder. When people with celiac disease eat gluten, the immune system attacks and damages the villa, which are small fingerlike projections lining the small intestine. In the United States, celiac disease affects about 1% of the population.
In adults, celiac disease is approximately two to three times as prevalent in women as in men. If you have celiac disease, you may experience malabsorption, nutritional deficiencies, weight loss, fatigue, abdominal pain, vomiting, or diarrhea. It is well established that glutens are responsible for celiac disease. In addition to wheat, gluten is also found in barley and rye and their byproducts.
In celiac disease, antibodies are targeted against gluten as well as against an enzyme normally present in the intestine called tissue transglutaminase. The antibodies produced in those with celiac disease are IgA or IgG, rather than IgE-type antibodies (which are associated with wheat allergy). Initial diagnosis is generally made by measuring IgA antibody levels to tissue transglutaminase in those individuals who are currently eating a diet that contains gluten. The antibody will not be produced or detected in those who are on a gluten-free diet. Diagnosis can be further confirmed by a biopsy to determine if there is damage to the villa of the small intestine. A gluten-free diet is the only known treatment known to be effective. By adhering to a strict gluten-free diet, one can improve symptoms and reduce the risk of developing complications.
Wheat allergy is also caused by an immune reaction, but it is not an autoimmune disease. It is an IgE-mediated allergy, comparable to peanut allergy. Diagnosis of wheat allergy is made through a combination of skin prick tests, measurement of IgE antibody levels, and oral food challenges. In wheat allergy, unlike celiac disease, damage to cells on the intestinal villa is not observed. Symptoms of wheat allergy can be mild to life-threatening. Reactions can be immediate or delayed. Common symptoms include eczema, hives, hay fever, and swelling of tissues. Life-threatening anaphylactic shock can also occur in severe cases. In a small amount of susceptible individuals, exercising within 3 hours of consumption of wheat products, can lead to symptoms of anaphylaxis. This is termed “wheat dependent exercise-induced anaphylaxis.”
Wheat allergy is also seen in individuals who come in frequent contact with wheat flour and symptoms result from inhaling the flour (baker’s asthma) or continued skin contact. Between 4–25% of bakery workers are affected by prolonged exposure to wheat products. Some of the symptoms of baker’s asthma include sneezing, coughing, skin rash, wheezing, and shortness of breath. Skin manifestations from contact include eczema and itching.
Currently, as there are no approved treatments for wheat allergy, avoidance of products containing wheat is the only way to prevent symptoms. Mild symptoms, caused by accidental ingestion of wheat, can generally be managed with antihistamines. However, the prompt use of epinephrine is critical during severe anaphylactic reactions. Immunotherapy is showing promise but is still considered experimental and has not yet been approved by the FDA for treatment of food allergies. During immunotherapy, the allergen is given regularly in increasing amounts to enable the body to adapt and increase tolerance to the allergen. The Sean N. Parker Center for Allergy and Asthma Research at Stanford University is one of several sites participating in a Phase 2 clinical trial for wheat immunotherapy. Further information regarding this study can be found at the clinical trials website.
Non-celiac wheat sensitivity
In recent years, it has been recognized that a number of patients have symptoms on consuming wheat, but they do not fit the diagnosis of either celiac disease or wheat allergy. This has led to the definition of a new condition called ‘non-celiac wheat sensitivity’ (NCWS). Another term for this disease that is commonly used in the literature is ‘non-celiac gluten sensitivity’ (NCGS). As it is now recognized that other factors in wheat — in addition to gluten — may be responsible for the disease, the term NCWS is gaining more acceptance. Wheat also contains small fermentable carbohydrates, which have been termed FODMAPs (Fermentable, Oligo-, Di-, Monosaccharides And Polyols). It is thought that elimination of FODMAPs from the diet and the resulting decreased fermentation in the colon improves symptoms. Individuals who eat a gluten-free diet often see improvements in their symptoms and this is likely because of the low content of FODMAPs in gluten-free products. Further information on the FODMAPS diet can be found at Stanford’s low FODMAP diet website. The symptoms of the disease are vague and nonspecific, affecting the digestive system (abdominal pain, bloating), skin (rash), and general well-being (fatigue, headache). The causes underlying this disease are not well understood and this lack of understanding poses a challenge for diagnosis. Diagnosis is currently made by excluding celiac disease and wheat allergy and by individuals reporting positive effects on eliminating gluten or wheat from their diet.
By Vanitha Sampath
Vanitha Sampath received her PhD in Nutrition from the University of California at Davis. At the Sean N. Parker Center for Allergy and Asthma Research, as a medical writer and content manager, she enjoys being in the midst of groundbreaking research in asthma and allergy and is committed to communicating the scientific advances of the Center and spreading awareness of its mission and vision.