Gluten Sensitivity in Those Without Celiac Disease
Gluten Sensitivity in Those Without Celiac Disease
Background: It is unknown whether symptoms in non-coeliac patients (non-CD) meeting clinical diagnostic criteria for noncoeliac gluten sensitivity (NCGS) are specifically triggered by gluten.
Aim To assess gluten sensitivity in patients diagnosed with NCGS.
Methods: We studied 35 non-CD subjects (31 females) that were on a gluten-free diet (GFD), in a double-blind challenge study. Participants were randomised to receive either gluten-containing flour or gluten-free flour for 10 days, followed by a 2-week washout period and were then crossed over. The main outcome measure was their ability to identify which flour contained gluten. Secondary outcome measures were based upon Gastrointestinal Symptoms Rating Scale (GSRS) scores.
Results: The gluten-containing flour was correctly identified by 12 participants (34%), who were classified as having NCGS. Their mean GSRS dimension scores were significantly higher following gluten challenge compared to baseline. The scores were: 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; diarrhoea, 1.6 ± 0.7 vs. 2.9 ± 1.5 and constipation, 1.9 ± 0.9 vs. 2.9 ± 1.3. Seventeen participants (49%) erroneously considered the gluten-free flour to contain gluten. Their mean 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; diarrhoea, 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.
Conclusion: Double-blind gluten challenge induces symptom recurrence in just one-third of patients fulfilling the clinical diagnostic criteria for non-coeliac gluten sensitivity.
The perception that gluten causes gastrointestinal and extra gastrointestinal symptoms in patients who do not have coeliac disease (CD), and are not allergic to wheat, is an increasing clinical problem. It is thought that there are now more people taking a gluten-free diet (GFD) following a self-diagnosis of gluten intolerance than there are with CD. This has been called noncoeliac gluten sensitivity (NCGS) in an international consensus statement. However, it is purely a clinical diagnosis as, in contrast to CD, it has no biomarker or characteristic intestinal biopsy findings. Currently, its existence remains controversial, and if it does exist, its cause and prevalence are unknown. The name NCGS implies that gluten is the trigger for the reported symptoms. However, other components in cereal could be responsible.
Three studies have recently explored the role of gluten in causing NCGS. A randomised, placebo controlled, cross-over trial in Italian patients with self-diagnosed gluten sensitivity, showed a small, but statistically significant, deterioration in reported symptoms when they were challenged with gluten in comparison to when they were challenged with placebo. A double-blind, placebo controlled parallel group study from Australia, found evidence of a specific effect of gluten. However, this was not confirmed by a subsequent controlled dietary study with a cross-over design, undertaken by the same group. This found evidence that people who avoid gluten-containing food are more likely to be sensitive to poorly absorbable carbohydrates, which are more abundant in gluten-containing than in gluten-free cereals, than to gluten itself. These carbohydrates include oligosaccharides, fructans and galacto-oligosaccharides. They have been termed Fermentable Oligo- Di- Mono- saccharides And Polyols (FODMAPs), and they are capable of triggering symptoms in patients with inflammatory bowel disease (IBS); gluten-containing diets, but low in FODMAPs, reduce symptoms in IBS. This suggests that the benefits of a GFD in some patients diagnosed with NCGS, may not be a consequence of the elimination of gluten, but rather may be due to their reduced intake of FODMAPs.
The aim of our study was to assess the prevalence of NCGS in a cohort of patients without CD or wheat allergy and fulfilling the currently accepted clinical criteria for NCGS who were taking a GFD on their own initiative. Their responses to challenges with gluten-containing vs. gluten-free flour were assessed in a double-blind manner, using a cross-over design.
Summary and Introduction
Summary
Background: It is unknown whether symptoms in non-coeliac patients (non-CD) meeting clinical diagnostic criteria for noncoeliac gluten sensitivity (NCGS) are specifically triggered by gluten.
Aim To assess gluten sensitivity in patients diagnosed with NCGS.
Methods: We studied 35 non-CD subjects (31 females) that were on a gluten-free diet (GFD), in a double-blind challenge study. Participants were randomised to receive either gluten-containing flour or gluten-free flour for 10 days, followed by a 2-week washout period and were then crossed over. The main outcome measure was their ability to identify which flour contained gluten. Secondary outcome measures were based upon Gastrointestinal Symptoms Rating Scale (GSRS) scores.
Results: The gluten-containing flour was correctly identified by 12 participants (34%), who were classified as having NCGS. Their mean GSRS dimension scores were significantly higher following gluten challenge compared to baseline. The scores were: 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; diarrhoea, 1.6 ± 0.7 vs. 2.9 ± 1.5 and constipation, 1.9 ± 0.9 vs. 2.9 ± 1.3. Seventeen participants (49%) erroneously considered the gluten-free flour to contain gluten. Their mean 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; diarrhoea, 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.
Conclusion: Double-blind gluten challenge induces symptom recurrence in just one-third of patients fulfilling the clinical diagnostic criteria for non-coeliac gluten sensitivity.
Introduction
The perception that gluten causes gastrointestinal and extra gastrointestinal symptoms in patients who do not have coeliac disease (CD), and are not allergic to wheat, is an increasing clinical problem. It is thought that there are now more people taking a gluten-free diet (GFD) following a self-diagnosis of gluten intolerance than there are with CD. This has been called noncoeliac gluten sensitivity (NCGS) in an international consensus statement. However, it is purely a clinical diagnosis as, in contrast to CD, it has no biomarker or characteristic intestinal biopsy findings. Currently, its existence remains controversial, and if it does exist, its cause and prevalence are unknown. The name NCGS implies that gluten is the trigger for the reported symptoms. However, other components in cereal could be responsible.
Three studies have recently explored the role of gluten in causing NCGS. A randomised, placebo controlled, cross-over trial in Italian patients with self-diagnosed gluten sensitivity, showed a small, but statistically significant, deterioration in reported symptoms when they were challenged with gluten in comparison to when they were challenged with placebo. A double-blind, placebo controlled parallel group study from Australia, found evidence of a specific effect of gluten. However, this was not confirmed by a subsequent controlled dietary study with a cross-over design, undertaken by the same group. This found evidence that people who avoid gluten-containing food are more likely to be sensitive to poorly absorbable carbohydrates, which are more abundant in gluten-containing than in gluten-free cereals, than to gluten itself. These carbohydrates include oligosaccharides, fructans and galacto-oligosaccharides. They have been termed Fermentable Oligo- Di- Mono- saccharides And Polyols (FODMAPs), and they are capable of triggering symptoms in patients with inflammatory bowel disease (IBS); gluten-containing diets, but low in FODMAPs, reduce symptoms in IBS. This suggests that the benefits of a GFD in some patients diagnosed with NCGS, may not be a consequence of the elimination of gluten, but rather may be due to their reduced intake of FODMAPs.
The aim of our study was to assess the prevalence of NCGS in a cohort of patients without CD or wheat allergy and fulfilling the currently accepted clinical criteria for NCGS who were taking a GFD on their own initiative. Their responses to challenges with gluten-containing vs. gluten-free flour were assessed in a double-blind manner, using a cross-over design.
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