Nutrition Research > Gluten
GLUTEN
Quick Facts
Gluten is a plant protein unique to wheat. Gluten is also unique in its functional contribution to the foods we love.
Celiac disease and wheat allergies are critical health issues. People diagnosed with these conditions should avoid consumption of foods made with wheat.
For those without a medical reason to avoid wheat-based foods or gluten, there may be unintended dietary impacts such as lower intake of dietary fibre and key vitamins and minerals.
Subjects Explored
What is Gluten?
What about gluten?
Gluten is a protein found in wheat, rye, barley, and triticale. When water is added to wheat flour, the gluten is formed and works like an elastic net stretching and trapping the air bubbles to create the chewy bread and light fluffy cakes we enjoy.
If it seems like there is gluten in everything, it’s because wheat is a common ingredient in breads, baked goods, pastas, and cereals. It’s also in beer and malt vinegar and used for thickening sauces. Gluten is found everywhere that wheat is present.
Celiac disease
Celiac disease is a serious autoimmune disorder where the surface of the small intestines that absorb nutrients is damaged by the ingestion of gluten.
When people with celiac disease eat gluten, their body mounts an immune response to attack the small intestine (which is where the gluten is being absorbed by the body). These attacks are what lead to damage of the small intestine. This results in symptoms such as:
- Diarrhea
- Abdominal pain
- Weight loss
- Malabsorption of nutrients
Other symptoms of celiac disease include anemia, fatigue, oral ulcers, and constipation. Although well-known, celiac disease is thought to affect about 1% of the population.
This autoimmune disease has a genetic component and is hereditary, meaning it can be common in families and can be diagnosed at any age.
Diagnosis is most commonly achieved through a blood test that looks for antibodies (IgA anti-tissue transglutaminase) followed by a biopsy of the small intestine to confirm the diagnosis. Genetic testing can be helpful to help rule out celiac disease.
There is no cure for celiac disease so strict adherence to a gluten-free diet and nutritional management by a knowledgeable professional is necessary.
For more information and resources about celiac disease, please visit the Canadian Celiac Association here.
Dermatitis herpetiformis
Dermatitis herpetiformis is referred to as ‘celiac disease of the skin’ because it presents as a skin rash with intense itching and burning after the ingestion of gluten. This is an uncommon disorder affecting about 10 people per 100,000 (or 0.0001% of the population). It typically presents later in life, in people over the age of 40.
Many factors may contribute such as genetics and the immune system, but the precise biological mechanisms remain unknown.
Often appearing as symmetrical rashes (on elbows, knees) this rash is diagnosed with a skin biopsy.
Wheat allergy
Similar to a peanut or other food allergy, a wheat allergy is a serious condition in which an immune response occurs after consuming wheat proteins. It includes symptoms such as swelling of the mouth, hives, difficulty breathing, and anaphylaxis, requiring immediate medical attention. It is not related to celiac disease or non-celiac gluten sensitivity.
Gluten sensitivities and intolerance
Non-celiac gluten sensitivity (NCGS), also called gluten intolerance or sensitivity, is a condition where an individual may test negative for celiac disease or a wheat allergy, but still experience symptoms such as bloating, excess gas, abdominal pain, diarrhea, headache and a runny nose after consuming products containing gluten. These symptoms can occur hours or days after ingesting gluten, and severity is determined by the amounts of food eaten.
Celiac disease and gluten sensitivity both cause gastrointestinal symptoms, so before gluten sensitivity can be diagnosed, it’s important to first rule out celiac disease.
There is currently no accepted method of confirming a diagnosis of NCGS by using tests or looking for markers in our body (such as compounds in our blood or urine). As it is often self-diagnosed, the prevalence is unknown. Recent studies are mixed when determining the prevalence of NCGS, with estimates ranging from less than that of celiac disease to upwards of 10% of the population.
Treating gluten sensitivity also requires a gluten-free diet; however, there may be more flexibility in this diet compared to someone with celiac disease because of the less severe symptoms and damage to the intestines.
This condition is relatively new and poorly understood as more research is required to determine the cause, mechanism, diagnosis methods, and management of the symptoms.
It’s important to note that NCGS also overlaps with fructose malabsorption. For many individuals, removing fructose and fructo-oligosaccharides from the diet is a successful treatment.
The popularity of gluten-free diets has grown, leading to more gluten-free claims in the marketplace.
According to consumer surveys, Canadians believe gluten-free foods are healthier than gluten-containing foods and about 25% of consumers purchase gluten-free foods with the purpose of managing their weight. In fact, unless medically necessary, avoiding gluten-containing foods means individuals may miss out on the benefits of fibre and micronutrients including vitamin D, vitamin B12, folate, calcium, and magnesium.
Gluten-free food substitutions
Gluten-free food products are extremely important for people who need to avoid gluten or wheat, but they don’t always stack up nutritionally. Many products made with wheat are fortified and enriched with important vitamins and minerals you need in your diet, but gluten-free substitutions made with rice or other grains may not be fortified or enriched with any additional vitamins and minerals.
In Canada, gluten-free staple foods such as bread, cereals, flours, and pastas can have less iron, folate, protein, and fibre, so it’s important to check the label carefully. You can read more about the benefits of fortification and enrichment here.
Some individuals without celiac disease have reported improvement in digestive symptoms following a gluten-free diet, which can give the impression that they have a gluten sensitivity or intolerance. However, this improvement could be due to the addition of high-quality, nutrient-dense foods in their diet such as an increased intake of fruits and vegetables to replace lower-quality food choices.
Research suggests that gluten-free diets can be lower in fibre and micronutrients including vitamin D, vitamin B12, folate, calcium, and magnesium due to the avoidance of several foods naturally rich in fibre like grains.
