Dietary and symptom assessment in adults with self-reported non-coeliac gluten sensitivity.

BACKGROUND & AIMS: The mechanisms behind non-coeliac gluten sensitivity (NCGS) are not fully understood although clinical symptoms have shown to subside after wheat withdrawal. Self-prescription of a gluten-free diet (GFD) without medical supervision is common in NCGS subjects, resulting in dietary restrictions that can cause macro- and micronutrient deficiencies. The primary aim was to describe dietary intake, including FODMAP, in subjects with self-reported gluten sensitivity on GFD in whom coeliac disease (CD) and wheat allergy were excluded. Secondary, clinical symptoms and health-related quality of life (HR-QoL) were examined. METHODS: Baseline characteristics were obtained from 65 adults with self-reported NCGS on GFD recruited to a randomised placebo-controlled challenge trial at Oslo University Hospital. Dietary intake was obtained by a seven-day food record and symptoms recorded by questionnaires. RESULTS: Mean proportions of energy were 43 E% from fat, 40 E% from carbohydrate and 17 E% from protein. Intakes of vitamin D, folic acid, calcium, iodine and iron were lower than recommended, mean (SD) 7.3 (5.8) µg, 235 (105) µg, 695 (309) mg, 81 (52) µg and 9.6 (7.5) mg, respectively. Mean (SD) intake of FODMAP was 11.6 g (8.7). Gastrointestinal symptoms as scored by 100 mm visual analogue scale (VAS) were all below 15 mm of which wind and bloating were the most expressed. Tiredness, concentration difficulties, fatigue and muscle/joint pain were scored highest among extra-intestinal symptoms. Gastrointestinal symptoms as scored by gastrointestinal symptom rating scale - irritable bowel syndrome version (GSRS-IBS) were correlated with mild depression (r = 0.43) and inversely correlated with five sub-domains of HR-QoL (-0.29 < r < -0.26). CONCLUSION: Subjects with self-reported NCGS on GFD had high proportion of energy from fat and sub-optimal intakes of vitamin D, folic acid, calcium, iodine and iron. Despite GFD and moderate intake of FODMAP, the subjects reported various gastro- and extra-intestinal symptoms and reduced HR-QoL. The findings highlight the importance of dietary education and nutritional follow-up of subjects on GFD.

Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity.

BACKGROUND & AIMS: Non-celiac gluten sensitivity is characterized by symptom improvement after gluten withdrawal in absence of celiac disease. The mechanisms of non-celiac gluten sensitivity are unclear, and there are no biomarkers for this disorder. Foods with gluten often contain fructans, a type of fermentable oligo-, di-, monosaccharides and polyols. We aimed to investigate the effect of gluten and fructans separately in individuals with self-reported gluten sensitivity. METHODS: We performed a double-blind crossover challenge of 59 individuals on a self-instituted gluten-free diet, for whom celiac disease had been excluded. The study was performed at Oslo University Hospital in Norway from October 2014 through May 2016. Participants were randomly assigned to groups placed on diets containing gluten (5.7 g), fructans (2.1 g), or placebo, concealed in muesli bars, for 7 days. Following a minimum 7-day washout period (until the symptoms induced by the previous challenge were resolved), participants crossed over into a different group, until they completed all 3 challenges (gluten, fructan, and placebo). Symptoms were measured by Gastrointestinal Symptom Rating Scale Irritable Bowel Syndrome (GSRS-IBS) version. A linear mixed model for analysis was used. RESULTS: Overall GSRS-IBS scores differed significantly during gluten, fructan, and placebo challenges; mean values were 33.1 ± 13.3, 38.6 ± 12.3, and 34.3 ± 13.9, respectively (P = .04). Mean scores for GSRS-IBS bloating were 9.3 ± 3.5, 11.6 ± 3.5, and 10.1 ± 3.7, respectively, during the gluten, fructan, and placebo challenges (P = .004). The overall GSRS-IBS score for participants consuming fructans was significantly higher than for participants consuming gluten (P = .049), as was the GSRS bloating score (P = .003). Thirteen participants had the highest overall GSRS-IBS score after consuming gluten, 24 had the highest score after consuming fructan, and 22 had the highest score after consuming placebo. There was no difference in GSRS-IBS scores between gluten and placebo groups. CONCLUSIONS: In a randomized, double-blind, placebo-controlled crossover study of individuals with self-reported non-celiac gluten sensitivity, we found fructans to induce symptoms, measured by the GSRS-IBS. Clinicaltrials.gov no: NCT02464150.