In what might be considered one of the largest growing health trends in recent times, many people have been moving to a gluten-free diet, with many people adopting the view that gluten is unhealthy for everyone, regardless of proven intolerance. Is this recent health kick supported by science?
Firstly, let's define gluten and its association with Coeliac disease. Gluten refers to certain proteins found in barley, oats, wheat and rye. The primary concern when it comes to gluten is for its potential to cause an inflammatory autoimmune condition known as Coeliac disease which affects around 1% of the world's population. Coeliac disease is an important medical condition with the potential to cause significant bowel symptoms and nutrient deficiencies that can lead to conditions such as anaemia and osteoporosis. Left untreated, Coeliac disease also carries a 10% lifetime risk of small bowel cancer, thus further highlighting the importance of accurate diagnosis and strict avoidance of gluten in affected individuals. Since Coeliac disease affects just 1% of the population, why is it that 12% of Australians are avoiding wheat and gluten?
Non-coeliac gluten sensitivity refers to a recognised medical condition whereby individuals experience sensitivity to gluten manifesting as symptoms such as abdominal pain, bloating, diarrhoea, and/or constipation, as well as potential to affect cognition, memory and alertness or cause joint and muscle pain, fatigue, dermatitis and anaemia. Diagnosis of this condition is difficult, and given the lack of recognised clinical biomarkers on blood tests or otherwise, diagnosis remains clinical based on resolution of symptoms following withdrawal of gluten. Symptoms may also overlap with other conditions such as irritable bowel syndrome (IBS) and intolerances such as lactose intolerance, with the exception that gluten is recognised as the primary trigger. Incidence of this condition is unknown, but it is thought to be more common than Coeliac disease.
Thus, while there is no strong evidence that gluten itself is unhealthy, it is possible for people to be intolerant to gluten in the absence of confirmed Coeliac disease. For those experiencing symptoms in keeping with either of these conditions, it is important to first exclude a diagnosis of Coeliac disease due to the significant long-term consequences of misdiagnosis. In the remaining symptomatic population, a trial of gluten-free diet may be appropriate to determine if symptoms improve after going gluten-free. For everyone else, there is no good evidence that avoidance of gluten leads to improved health outcomes.
References:
1. Leonard, M., Sapone, A., Catassi, C., & Fasano, A. (2017). Celiac Disease and Nonceliac Gluten Sensitivity. JAMA, 318(7), 647-656.