Celiac.com 11/30/2015 - A new study by researchers in Italy shows that only a minority of patients who meet clinical criteria for non-celiac gluten sensitivity actually show symptoms when exposed to gluten in a controlled gluten challenge. Why is that?

Photo: CC--Dean HochmanResearchers haven't had much good information on whether symptoms in people who meet clinical diagnostic criteria for non-celiac gluten sensitivity (NCGS) are specifically triggered by gluten. To provide better information, a team of researchers recently set out to assess gluten sensitivity in patients diagnosed with NCGS.

The research team includes B. Zanini; R. Basché; A. Ferraresi; C. Ricci; F. Lanzarotto; M. Marullo; V. Villanacci; A. Hidalgo; and A. Lanzini. They are variously affiliated with Department of Gastroenterology, and the Department of Pathology at the University and Spedali Civili of Brescia, Brescia, Italy, and the Department of Food, Environmental and Nutritional Sciences at the University of Milan, Milan, Italy.

For their in a double-blind challenge study, their team looked at 31 females and 4 males without celiac disease, who were following a gluten-free diet (GFD). Participants were randomly broken into groups that received either gluten-containing flour or gluten-free flour for 10 days, followed by a 2-week washout period, followed by a switch in gluten-free/non-gluten-free diets.

The main outcome measure was the test subjects' ability to identify which flour contained gluten. Secondary outcome measures were based upon Gastrointestinal Symptoms Rating Scale (GSRS) scores.

Only 12 participants (34%) classified as having NCGS correctly pointed out the gluten-containing flour. These participants showed much higher average GSRS dimension scores following gluten challenge compared to baseline.

The team measured scores for: pain, 1.7 ± 0.8 vs. 2.6 ± 1.0; reflux, 1.6 ± 0.5 vs. 2.2 ± 0.9; indigestion, 1.9 ± 0.7 vs. 3.2 ± 1.1; diarrhea, 1.6 ± 0.7 vs. 2.9 ± 1.5 and constipation, 1.9 ± 0.9 vs. 2.9 ± 1.3.

Seventeen participants, nearly half, erroneously considered the gluten-free flour to contain gluten. Their average GSRS dimension scores were significantly higher following gluten-free flour challenge compared to baseline.

The scores were: pain, 1.6 ± 0.9 vs. 3.0 ± 0.9; reflux, 1.4 ± 0.5 vs. 2.3 ± 1.1; indigestion, 2.0 ± 1.1 vs. 3.7 ± 1.1; diarrhea, 1.6 ± 0.7 vs. 3.0 ± 1.2 and constipation, 1.6 ± 0.9 vs. 2.6 ± 1.3.

The other six participants (17%) were unable to distinguish between the flours.

Based on this study, only about one in three patients with clinical non-celiac gluten sensitivity showed an adverse reaction to gluten.

Clearly, more needs to be done to determine the exact nature of non-celiac gluten-sensitivity, and to determine what, if anything, may be driving these adverse reactions that can be triggered by non-gluten containing foods.

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