Gluten Intolerance, Wheat Intolerance, Wheat Allergy, Celiac Disease

Wheat is a staple part of diets across the globe, and more in certain regions. It is the main ingredient in the various breads of different nations and cultures but is also present in a host of other foods. Despite being a widely consumed food ingredient, some people are unable to tolerate wheat for various reasons. This may be due an intolerance to wheat, an allergy trigger by wheat or an autoimmune response due to the presence of wheat in the gut.

How does wheat affect the body?

Depending on the wheat-related condition in question, the mechanism by which it causes disturbances varies. These conditions can be broadly divided into an intolerance, allergy or autoimmune reaction.

• Intolerance refers to the body’s inability to digest a specific nutrient which then remains in the gut where it causes a host of digestive disturbances.
• Allergy refers to an immune-mediated reaction whereby the presence of a substance triggers the immune system to respond to the substances as a threat.
• Autoimmune refers to conditions where there is inflammation mediated by the immune system due to the cross-reaction between a specific substance or agent and that of specific tissues in the body.

Therefore there may be a wheat intolerance, wheat allergy or wheat-related autoimmune diseases like celiac disease. The exact reason why some people develop these senstivities towards wheat or gluten is not always clear. Genetic factors have been implicated in certain conditions but this does not always account for all of the gluten and wheat related conditions discussed below.

Read more on gluten sensitivity and wheat allergy.

Gluten Intolerance

Some people have diarrhea after ingesting gluten-containing food (wheat, rye, barley) but have no intestinal changes and no characteristic antibodies tTG IgA, EMA igA found in the blood. This condition is called gluten intolerance and it is not an immune disorder (1). The term is often mistakenly used for celiac disease. Prevention is through a gluten-free diet.

In recent times there has been questions raised about the validity of the condition referred to as gluten intolerance. In fact the condition may rather be a sensitivity to wheat, and not necessarily just gluten specifically, which then gives rise to the symptoms that are broadly referred to as gluten intolerance. The mechanism in gluten intolerance (or more correctly in gluten sensitivity) is not the same as that of lactose intolerance.

Wheat Intolerance

Some people have diarrhea after ingesting wheat but can eat rye and barley without problems. They do not have tTG or EMA igA antibodies in the blood and no small intestinal changes characteristic for celiac disease. Prevention through a wheat-free diet. Contrary to previous ideas about gluten intolerance and wheat intolerance, it appears that both conditions are probably the same entity.

As is the case with gluten intolerance, there may be a sensitivity to wheat and this is not necessarily due to the gluten in the wheat. Therefore the preferred term may rather be gluten sensitivity or wheat sensitivity. Unlike with other intolerances, like lactose intolerance, there is no  deficiency of any specific enzyme that may make wheat indigestible in the gut. Therefore the exact reason for this sensitivity to wheat is unclear.

Wheat Allergy

A wheat allergy is mainly seen in children. An allergic reaction is triggered by contact with wheat which an aggravation of dermatitis (eczema), asthma or allergic rhinitis after ingesting wheat (2). It is considered as one of the most allergenic foods in atopy. Diagnosis is confirmed by skin prick test. IgE antibodies and eosinophils are usually elevated in the blood. Wheat allergy with atopy often (but not always) disappears until adulthood. Prevention is by wheat-free diet. If this does not help, other food allergies have to be considered.

This type of wheat allergy should not be mistaken with an anaphylactic reaction. In anaphylaxis, a harmless substances may cause a widespread allergic response lead to inflammation of the skin, swelling of the throat tissue and other reactions. It can be life threatening without prompt medical attention. However, this type of reaction is not usually seen with wheat exposure or consumption.

Celiac Disease

Some people experience diarrhea, bloating, tiredness, skin rash and several other symptoms after ingesting wheat, rye or barley, all of which contain gluten. If tTG and EMA IgA antibodies are found in the blood, and duodenal biopsy shows characteristic intestinal changes. This confirms celiac disease. In inconclusive cases, a genetic test may be done.

If this test is negative, then it conclusively excludes celiac disease. Prevention is through a gluten-free diet. Celiac disease is not an allergy as was previously thought. Instead it appears to an immune mediated reaction which is autoimmune in nature. The presence of wheat triggers the immune system which then attacks the bowel wall leading to inflammation. This further impairs absorption of other nutrients and normal bowel functioning.

How to Know if Wheat is a Problem?

Due to the varied nature of the wheat and gluten related conditions discussed below, it is not always obvious that wheat is a problem except in conditions like celiac disease where symptoms arise shortly after wheat exposure. However, if it is problem then symptoms should arise within minutes to hours after consuming a food made with wheat, and particularly those foods that are comprised to a large degree out of wheat like with flour.

• Nausea and sometimes vomiting
• Abdominal pain or cramps
• Diarrhea
• Bloating
• Indigestion
• Fatigue
• Irritability

Many people also experience other digestive symptoms like heartburn after consuming wheat. Heartburn is a consequence of acid reflux. Although there is no conclusive link between wheat and gastroesophageal reflux disease (GERD), this could be a result of gluten sensitivity which presents with symptoms that cannot always be explained by wheat exposure but nevertheless is reported by sensitive individuals.

Specific symptoms may arise when wheat is an allergen in sensitive individuals and triggers or worsens conditions such as atopic dermatitis (eczema), asthma or allergic rhinitis. These symptoms may then arise:

• Itchy skin
• Shortness of breath
• Wheezing
• Runny nose
• Sneezing

References:

1. Gluten intolerance  (celiacdisease.net)
2. Wheat allergy  (aafa.org)