Non-celiac gluten sensitivity (NCGS) is defined as intestinal and non-intestinal symptoms resulting from the ingestion of gluten, and which is not due to celiac disease (CD) or wheat allergy. Gluten sensitivity appears to be increasing and is thus a topic of significant public and research interest; a recent paper published in the journal Nutrients describes progress in the field from a meeting of experts.1 Some common questions about gluten sensitivity are posed below, illustrating that while some basics are clear, there is much yet to unravel about the cause of NCGS.
What is gluten?
Wheat gluten is a protein composite of gliadin and glutenin proteins (seed storage protein members of the prolamin and glutelin families, respectively) found in the wheat endosperm.
What is the problem with gluten?
It is not yet clear, but incomplete gluten digestion may trigger an immune response to certain gluten peptide fragments, leading to NCGS, wheat allergy or celiac disease in genetically predisposed individuals. Increasingly, there are reports of individuals following a gluten free or restricted diet to relieve their abdominal pain, bloating and fatigue, among other symptoms, and that these problems recur when gluten is reintroduced into their diets.
Why is gluten sensitivity a growing issue?
The reasons for the growing trend in apparent gluten sensitivity are not known. Human consumption of gluten may be on the rise since it is increasingly used as a protein supplement in foods, and thus present in many prepared food items in addition to common and highly popular food products containing wheat flour such as breads, crackers, pizzas, pasta and baked goods. However, NCGS may result from other dietary factors present in wheat, or due to multiple other possibilities, acting alone or in concert, such as wheat agriculture or food production methods affecting gluten or wheat, or gut bacteria composition/reaction to wheat products.
How widespread is the gluten problem?
There are indications that gluten sensitivity might be significantly more prevalent than previously thought. A large study (920 subjects) has found that 30% of subjects with irritable bowel syndrome (IBS)-like symptoms in fact had wheat sensitivity.2 IBS is estimated to occur in 16-25 % of the adult population in Northern Europe3,4; if 30% of IBS sufferers have a wheat sensitivity that falls under NCGS, it points to an unusually common, and until recently, mostly hidden cause of digestive distress. The most prevalent symptoms of NCGS are IBS-like symptoms of bloating, abdominal pain, bowel habit irregularities, headache, fatigue, muscle and joint pain, skin rashes, depression and anemia.1
What is the latest research in this field?
A recent paper, ‘Non-Celiac Gluten Sensitivity: The New Frontier of Gluten Related Disorders’1, in the journal Nutrients, describes the major advances and current trends. The review is based on a meeting of international experts and addresses multiple aspects including the clinical picture of NCGS and the availability of biomarkers and diagnostic criteria. The paper notes that there remain many open questions to be clarified and that while gluten ingestion may result in IBS-like symptoms, it cannot yet be determined to be the sole causative agent for what is now termed NCGS, and that symptoms might arise from other factors, such as wheat amylase trypsin inhibitors that protect against insect pests but may cause intestinal inflammation.1,5
1. Catassi, C.; Bai, J.C.; Bonaz, B.; Bouma, G.; Calabrò, A.; Carroccio, A.; Castillejo, G.; Ciacci, C.; Cristofori, F.; Dolinsek, J.; Francavilla, R.; Elli, L.; Green, P.; Holtmeier, W.; Koehler, P.; Koletzko, S.; Meinhold, C.; Sanders, D.; Schumann, M.; Schuppan, D.; Ullrich, R.; Vécsei, A.; Volta, U.; Zevallos, V.; Sapone, A.; Fasano, A. Non-Celiac Gluten Sensitivity: The New Frontier of Gluten Related Disorders. Nutrients 2013, 5, 3839-3853.
2. Carroccio, A.; Mansueto, P.; Iacono, G.; Soresi, M.; D’Alcamo, A.; Cavataio, F.; Brusca, I.; Florena, A.M.; Ambrosiano, G.; Seidita, A.; et al. Non-celiac wheat sensitivity diagnosed by double-blind placebo-controlled challenge: Exploring a new clinical entity. Am. J. Gastroenterol. 2012, 107, 1898–1906.
3. Krosgaard, L.R.; Engsbro, A.L.; Bytzer, P. The epidemiology of irritable bowel syndrome in Denmark. A population-based survey in adults < 50 years of age. Scand. J. Gastroenterol. 2013, 48, 523–299.
4. Breckan, R.K.; Asfeldt, A.M.; Straume, B.; Florholmen, J.; Paulssen, E.J. Prevalence, comorbidity, and risk factors for functional bowel symptoms: A population-based survey in Northern Norway. Scand. J. Gastroenterol. 2012, 47, 1274–1282.
5. Junker, Y.; Zeissig, S.; Kim, S.J.; Barisani, D.; Wieser, H.; Leffler, D.A.; Zevallos, V.; Libermann, T.A.; Dillon, S.; Freitag, T.L.; et al. Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toll-like receptor 4. J. Exp. Med. 2012, 209, 2395–2408.