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* Corresponding author: Hanna Fjeldheim Dale, email hanna.dale@outlook.com
Introduction
Cultivation of cereal crops and consumption of grains and cereal products have made gluten-containing grains a great part of human evolution and food habits since agricultural development began about 9000 years BC(1). Since the beginning of the agricultural revolution, the production and utilisation of wheat have gradually expanded globally, and today wheat-containing foods provide as much as up to 50 % of energy intake in both industrialised and developing countries, making it a vital part of the population’s diet(2).
Wheat contains carbohydrates (60–65 %), lipids (1–2 %), proteins (10–14 %) and water. Gluten is made up of a complex mixture of hundreds of different proteins that are collectively named gluten. The mixture is divided into the different protein complexes gliadin and glutenin. Gliadin is an alcohol-soluble fraction further divided into α-, β-, γ- and ω-gliadins; glutenin, which is an alcohol-insoluble substance, is further divided into high-molecular-weight and low-molecular-weight glutenins(3,4). The protein structure of wheat gluten is very similar to the proteins of rye (secalin) and barley (hordein) and, therefore, the term gluten is often used as a collective term to describe all of these components. Wheat also contains non-gluten proteins, such as amylase–trypsin inhibitors (ATI)(3).
During the last decade, the avoidance of wheat and other gluten-like-containing grains has increased worldwide, with the highest prevalence in the Western countries presumed to be 10–20 %(5,6). This decline in wheat intake is due to the fact that the ingestion of gluten has been putatively linked to a wide range of health complaints and clinical disorders, such as gastrointestinal symptoms including abdominal pain, skin lesions, migraines, weight gain, fatigue, depression and tiredness(7).
The spectrum of gluten-related disorders includes coeliac disease (CD), wheat allergy (WA) and the new entity non-coeliac gluten sensitivity (NCGS). The estimated global prevalence of these gluten-related disorders is about 5 %; however, the prevalence of individuals following a gluten-free diet (GFD) is much higher(8). The diagnosis of both CD and WA is relatively straightforward due to the presence of objective examinations and biomarkers. On the...