Non-coeliac gluten sensitivity and coeliac disease – Dietary and diagnostic aspects

Individuals with gluten sensitivity without coeliac disease report symptom relief of gastrointestinal symptoms as response to gluten-free diet (GFD). However, gluten is not likely the culprit. In the thesis Non-coeliac gluten sensitivity and coeliac disease – Dietary and diagnostic aspects, Gry Skodje and co-workers have shown that fructans, a carbohydrate, is the offending component in self-reported gluten sensitivity. They challenged study subjects with muesli bars added gluten, fructan or placebo in a randomised double blinded rechallenge with crossover. Fructans induced more symptoms than gluten. Coeliac disease (CD) is caused by an abnormal immune response to gluten and is identified by serology and intestinal biopsy. Self-reported gluten sensitivity lacks objective markers due to unknown pathology and is difficult to identify. The research group studied the GFD in these two groups and found that the self-reported gluten sensitive adhered as strictly to the diet as the coeliacs, despite lack of GFD education. They also found that wheat challenge in gluten sensitive subjects resulted in overestimation of the diagnosis. The gold standard to identify adverse reactions to food is double-blind placebo-controlled challenge. By using this method with gluten concealed in muesli bars, many study subjects appeared to react to placebo and not to gluten. The gluten containing muesli bars induced intestinal damage in coeliac patients after a 14 day challenge. However the changes were insufficient to confirm or exclude CD. The frequency of HLA-DQ:gluten tetramer-binding T-celles increased by more than 100 % on day 6 of the challenge in 12 of 15 subjects and is suggested as a specific and less invasive diagnostic method to detect or exclude CD in persons that are already on a GFD. Take-home message is that gluten sensitive subjects adhere as strictly to the GFD as coeliac subjects, however, fructans are more likely the culprit. This suggests that the condition rather should be regarded as a variant of irritable bowel syndrome