Oral Fructanase Administration Reduces Gastrointestinal Symptom Severity after Acute Inulin Challenge in Healthy Adults

Journal article, 2026

Background: Fructanase, an enzyme that hydrolyzes dietary fructans to fructose in vitro, may reduce gastrointestinal (GI) microbial fermentation in vivo by breaking down fructans before transit to the colon. Objectives: This study evaluated the effects of a microbial fructanase on GI symptoms and intestinal fermentation in males and females after inulin-type fructan ingestion. Methods: A randomized, double-blind, crossover study design was used with 30 healthy adults [mean (standard deviation) age: 38.6 (7.3) y and body mass index: 24.5 (3.0) kg/m²] who consumed 25 g inulin mixed into 40 g oatmeal with either 1 capsule containing fructanase or placebo maltodextrin. GI symptoms and fatigue were assessed using visual analog scales at baseline and postprandially for 24 h. Breath hydrogen and methane concentrations were measured postprandially hourly for 8 h. A Wilcoxon signed-rank test was used to compare paired differences between fructanase and placebo conditions. Results: The maximum 0 to 8 h overall abdominal symptom score was not statistically significant (P = 0.13) between groups. Compared with placebo, fructanase coadministration with inulin reduced abdominal pain (P = 0.044) and fatigue (P < 0.001). Rank-based repeated-measures analysis showed that fructanase reduced burping (P = 0.040) during the 0 to 8 h period. Over the 8 to 24 h period, fructanase reduced overall abdominal symptoms (P = 0.030), bloating (P = 0.011), abdominal pain (P = 0.019), and flatulence (P = 0.044). Breath hydrogen and methane outcomes did not differ significantly between groups. Conclusions: Fructanase coadministration with inulin reduced GI symptoms in healthy adults, suggesting that it may be a useful dietary supplement for fructan sensitivity. Further trials in a cohort with GI symptoms such as irritable bowel syndrome are warranted.This trial was registered at clinicaltrials.gov as NCT06628869 (https://clinicaltrials.gov/study/NCT06628869).