Schreiner P, et al. - In this investigation, researchers assessed the prevalence of vegetarian (VD) and gluten-free diets (GFDs) in inflammatory bowel disease (IBD) patients, the reasons for following such a diet, and whether nutrition affects disease activity and composition of microbiota. Between 2006 and 2015, they involved 1254 subjects from the Swiss Inflammatory Bowel Disease Cohort Study with a prospective acquisition of clinical data and psychosocial, disease-related and lifestyle factors. They analysed intestinal mucosa-associated microbial composition using high-throughput sequencing in 92 patients. There were no differences in the rates of disease, fistula, hospitalization or surgery. In IBD patients following a VD or GFD, the composition of gut microbiota was significantly different from that of omnivores. Although a relevant impact of a specific diet on the course of the disease was not identified, there was a significant association with lower psychological well-being in patients with VD and GFD.