The growing number of consumer foods and ingredients branded as “gluten-free” and/or “lactose-free” suggests that avoidance of specific dietary factors is common. CSIRO (Commonwealth Scientific and Industrial Research Organisation) survey data indicate that this behaviour is a real phenomenon, with one in seven adult Australian respondents not diagnosed with coeliac disease reporting avoidance of wheat or dairy foods. The behaviour is largely self-initiated, occurring predominantly without a formal medical diagnosis and is driven principally by adverse reactions attributed to those foods. Mostly, these comprise gastrointestinal symptoms that include bloating and cramps, commonly associated with irritable bowel syndrome. Wheat contains gluten, which provokes an immune reaction in susceptible individuals. However, the pattern of survey responses regarding symptoms does not suggest an allergenic or autoimmune cause; wheat avoiders do not seem to be undiagnosed coeliacs (Public Health Nutr 2014; 18: 490-499).
Our results raise several causes for concern. Translation of the data to the general population suggests that a significant proportion of adult Australians are at risk of nutritional imbalance. Wheat- and dairy-based foods are important sources of essential nutrients, so their exclusion could lead to dietary deficiencies (eg, of fibre, calcium) or, of equal concern, dietary imbalances caused by consumer overcompensation for perceived deficiencies. Clinically, self-diagnosis of symptoms of intolerance also carries the risk of delays in the identification and treatment of potentially serious medical conditions (BMJ 1988; 297: 719-720). For the majority of avoiders, the actual causes of symptoms and their mechanisms need to be established to improve condition diagnosis and management. Complicating matters is the issue of poly-avoidance, with more than 50% of wheat avoiders also avoiding dairy foods, and we need to establish whether the behaviours share a common aetiology. We also need to clarify whether consumers are making other self-prescribed dietary changes, either in response to their symptoms or in the belief that they are improving their personal health.
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