Dietary intake of inulin-type fructans in active and inactive Crohn's disease and healthy controls: a case-control study

Background and Aims: Prebiotic inulin-type fructans are widely consumed in the diet and may have contrasting effects in Crohn's disease by stimulating gut microbiota and/or by generating functional gastrointestinal symptoms. The aim of this study was to measure fructan and oligofructose intakes in patients with active and inactive Crohn's disease compared with healthy controls. Methods: Patients with active Crohn's disease (n = 98), inactive Crohn's (n = 99) and healthy controls (n = 106) were recruited to a case-control study. Dietary intake of inulin-type fructans was measured using a specific food frequency questionnaire and was compared between the three groups and between patients with different disease phenotypes (Montreal classification). Associations between intakes and disease activity (Harvey-Bradshaw Index, HBI) were also undertaken. Results: Patients with active Crohn's disease had lower fructan intakes (median 2.9 g/d, interquartile range [IQR] 1.8) than those with inactive Crohn's (3.6 g/d, 2.1, p = 0.036) or controls (3.9 g/d, 2.1, >p = 0.003) and lower oligofructose intakes (2.8 g/d, 1.8) than those with inactive Crohn's (3.5 g/d, 2.2, p = 0.048) or controls (3.8 g/d, 2.1, p = 0.003). There were no differences in intakes related to disease site or behaviour. There were negative correlations between HBI well-being score and fructan intake (rho = -0.154, p = 0.03) and oligofructose intake (rho = -0.156, p = 0.028) and for the HBI abdominal pain score and fructan (rho = -0.164, p = 0.021) and oligofructose intake (rho = -0.157, p = 0.027). Conclusions: Patients with active Crohn's disease consume lower quantities of fructans and oligofructose than their inactive counterparts and healthy controls. The impact of lower intakes of prebiotic fructans on gut microbiota is unknown and warrants further research.