Table 2.

Main characteristics of the studies regarding gluten intake or use of a gluten free diet in inflammatory bowel diseases.

Study	Type of Study	Population	Aim	Results
Triggs et al. [60], 2010	Observational study	An amount of 446 subjects with Crohn’s disease	Evaluation of the impact of GFD in IBD patients	Decreased number of flares and GI symptoms’ severity following a GFD (66%)
Zallot et al. [62], 2013	Observational study	An amount of 244 IBD patients	Evaluation of the impact of diet in IBD patients	An amount of 57.8% of the patients felt that food could play a pivotal role in IBD flares; 9.5% of patients believed that a GFD was helpful in improving their symptoms during the disease’s flares; only 1.6% of the study population decided to adopt a GFD during disease flares;
Herfarth et al. [61], 2014	Cross-sectional study	An amount of 1647 IBD patients	Investigate the adherence to GFD among IBD patients and their experience with it	An amount of 19.1% of the study population tried a GFD, while 8.2% of them were already following it. After following a GFD, 65.6% of the patients reported an improvement of the symptoms, 38.3% a reduction of disease flares’ frequency and severity, and 23.6% needed less medications
Schreiner et al. [63], 2019	Prospective study	An amount of 1254 IBD patients	Investigate the adherence to GFD among IBD patients and their experience with it	An amount of 4.7% of the study population followed a GFD and did not find any differences in disease activity, complications, and hospitalization rate Worse psychological wellbeing in those who were following a GFD diet
Morton et al. [51], 2020	Observational study	An amount of 233 IBD patients	Evaluation of the effects of GFD trial on IBD symptoms and flares	An amount of 66% of the patients reported an improvement of the symptoms and 38% reported reduced flare frequency and severity