This is a guest post by Dr. Umberto Volta from Bologna University (Italy). He tells us more about non-celiac gluten sensitivity and the multicenter prospective survey he coordinated on it, which was promoted by the Italian Association for Celiac Disease and has been published today in BMC Medicine.
As a pioneer of non-celiac gluten sensitivity (NCGS), I can testify that until a few years ago this syndrome was surrounded by such skepticism as to be confined to a ‘no man’s land’.
However, awareness of the existence of NCGS has grown so much that nowadays this syndrome is recognized all over the world. It’s one of the main topics at international gluten-related meetings, as it was at the 15th International Celiac Disease Symposium in Chicago last year.
What is non-celiac gluten sensitivity and who does it affect?
NCGS can be regarded as a syndrome characterized by a wide array of both gastrointestinal and extra-intestinal symptoms occurring within a few hours or days from someone ingesting gluten. The most frequent gastrointestinal manifestations are abdominal pain and bloating associated with diarrhea, constipation or alternate bowel habits. Among the extra-intestinal signs are a lot of neurological symptoms including foggy mind, headache and numbness, together with tiredness, fibromyalgia and skin rash. Symptoms quickly improve after gluten withdrawal and rapidly recur when gluten is reintroduced.
The epidemiology of NCGS is far from being established with little available data. In the USA its prevalence has been detected as varying from 0.6% in primary care in the National Health and Nutrition Examination Survey to 6% in tertiary care (in research from Maryland University). These varying results have been the subject of much debate.
Results suggest NCGS is more common than celiac disease
The Italian multicenter survey that I coordinated on NCGS, and which was performed in 38 tertiary centers for the diagnosis of gluten-related disorders, showed interesting results. By comparing the new diagnoses of NCGS and celiac disease, it has been assessed that NCGS is slightly the more frequent (1.15 to 1), though still rare in children (0.28 to 1).
Of the 486 NCGS patients identified in this study, the large majority were women (female/male: 5.5 to 1, mean age 38 years). Bloating, abdominal pain, tiredness, and neurological signs were the most frequent symptoms, with the large majority of patients complaining of disturbances every time they ate gluten-containing food. The symptoms occurred within a few hours or one day in more than 95% of cases.
In a recent interview with Scientific American, a group of experts including myself underlined that gluten proteins are not likely the only trigger of this syndrome.
Besides gluten, other wheat proteins such as amylase-trypsin inhibitors and fermentable oligo-mono-disaccharides and polyols (FODMAPs) could have a role in eliciting the clinical picture of NCGS. Interestingly, together with milk, legumes, honey, and some fruits and vegetables, common sources of FODMAPs include wheat and rye, the same cereals which contain gluten proteins.
Diagnosis, treatment and further research
NCGS is still a condition with several unsettled issues. One of the most critical aspects is the absence of biomarkers which makes it difficult to reach a clear-cut diagnosis. This implies that NCGS can be diagnosed only on the basis of the clinical response to gluten ingestion and withdrawal, as well as to gluten challenge after having ruled out both celiac disease and wheat allergy .
The gold-standard assay for confirming NCGS would require dietary elimination, followed by a double-blind, randomized, placebo-controlled food challenge. This procedure is difficult to adopt routinely in clinical practice.
There aren’t established guidelines for the treatment of patients with NCGS. People should not eliminate gluten from their diet without a specific recommendations being given by an expert physician.
Patients with NCGS are advised to consume gluten-free foods, which can be a challenge. Commercially available gluten-free products are useful to achieve a gluten-free regimen, but their consumption should be limited in order to reduce the introduction of chemical additives and preservatives, which are highly present in these products.
Further research is awaited to shed light on NCGS. The first objective is to identify a biomarker (i.e. antibodies, cytokines, chemokines) that allows us to confirm the diagnosis with certainty. The availability of such biomarkers would enable us to confirm the real prevalence of this syndrome in the general population, as has already happened for celiac disease.
Want to know more about non-celiac gluten sensitivity? Read the commentary to accompany Dr Volta’s study in BMC Medicine: ‘Non-celiac gluten sensitivity – why worry?‘