The reported prevalence of adverse reactions to wheat and gluten seems to have escalated in the past few years. This is reflected by the increase in sales of “free-from”, particularly wheat-free products.
A recent systematic review from the European Food Safety Authority indicated that prevalence rates of clinician-diagnosed wheat allergy range from 0.3% - 3.4%. in Europe although rates of sensitization to wheat as high as 13.9% was measured based on skin prick testing. There is however a lack of information about the true prevalence of food challenge proven wheat allergy. The few published studies utilising this method, estimate a wheat allergy prevalence of 0.1 – 0.6% in Europe [1, 2, 4, 5,6].For the rest of world, reported clinician diagnosed wheat allergy ranged between 0.1 – 0.5%. The highest rates of wheat sensitization was 2.2% .
The prevalence of wheat intolerance is unknown, primarily because of the difficulty of studying this due to the lack of clear definitions and the delayed and often subjectivity of the reactions. The prevalence of avoidance of “gluten containing foods” which may relate to wheat intolerance, coeliac disease or non-coeliac gluten sensitivity range between 0.6 – 41.2% depending on the population studied .
Wheat – a complex grain
Wheat is a complex food containing cross-reacting proteins to both other cereals and pollens. Wheat and cereals are composed of four classes of proteins; the water/salt soluble albumins and globulins and the water/salt insoluble gliadins and glutenins, which together are known as prolamins/gluten. Of these, there are two major proteins considered to lead to adverse reactions, the lipid transfer protein (LTP) and the omega-5 gliadins (both considered to be prolamins or seed storage proteins) . The albumins, globulins, and ‘gluten’ (gliadins and glutenins)  that may also cross-react with rye and barley.
It is important to take these factors into account when performing tests to confirm a wheat allergy: Wheat is a grass and the profilins in wheat are likely to cross-react with grass; not indicating the likelihood of reaction to consumption of wheat. [7,8,9]. Venter et al. recently reported high rates (78%) of coexisting positive wheat pollen SPT and specific IgE despite no clinical allergy. This was not the case for wheat flour and specific IgE to wheat .
- Osterballe, M., Hansen, T. K., Mortz, C. G., Host, A. and Bindslev-Jensen, C. (2005) 'The prevalence of food hypersensitivity in an unselected population of children and adults', Pediatr Allergy Immunol, 16(7), 567-73.
- Zuberbier, T., Edenharter, G., Worm, M., Ehlers, I., Reimann, S., Hantke, T., Roehr, C. C., Bergmann, K. E. and Niggemann, B. (2004) 'Prevalence of adverse reactions to food in Germany - a population study', Allergy, 59(3), 338-45.
- Venter, C., Pereira, B., Grundy, J., Clayton, C. B., Arshad, S. H. and Dean, T. (2006) 'Prevalence of sensitization reported and objectively assessed food hypersensitivity amongst six-year-old children: a population-based study', Pediatr Allergy Immunol, 17(5), 356-63.
- Venter, C., Pereira, B., Voigt, K., Grundy, J., Clayton, C. B., Higgins, B., Arshad, S. H. and Dean, T. (2008) 'Prevalence and cumulative incidence of food hypersensitivity in the first 3 years of life', Allergy, 63(3), 354-9.
- Ronchetti, R., Jesenak, M., Trubacova, D., Pohanka, V. and Villa, M. P. (2008) 'Epidemiology of atopy patch tests with food and inhalant allergens in an unselected population of children', Pediatr Allergy Immunol, 19(7), 599-604.
- Nam YH, Hwang EK, Jin HJ, Lee JM, Shin YS, Ye YM, Palacin A, Salcedo G, Lee SY, Park HS. Comparison of specific IgE antibodies to wheat component allergens in two phenotypes of wheat allergy. J Korean Med Sci. 2013 Nov;28(11):1697-9.
- Donovan GR, Baldo BA. Crossreactivity of IgE antibodies from sera of subjects allergic to both ryegrass pollen and wheat endosperm proteins: evidence for common allergenic determinants. Clin Exp Allergy 1990;20:501–509.
- Jones SM, Magnolfi CF, Cooke SK, Sampson HA. Immunologic cross-reactivity among cereal grains and grasses in children with food hypersensitivity. JAllergy Clin Immunol 1995;96:341–351.
- Sander I, Raulf-Heimsoth M, Duser M, Flagge A, Czuppon AB, Baur X. Differentiation between cosensitization and cross-reactivity in wheat flour and grass pollen-sensitized subjects. IntArch Allergy Immunol 1997;112:378–385.