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

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.

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.

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).

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.