Evaluation of gut microbiota of iranian patients with celiac disease, non-celiac wheat sensitivity, and irritable bowel syndrome: are there any similarities?

BACKGROUND AND AIMS: Individuals with celiac disease (CD), non-celiac wheat sensitivity (NCWS), and irritable bowel syndrome (IBS), show overlapping clinical symptoms and experience gut dysbiosis. A limited number of studies so far compared the gut microbiota among these intestinal conditions. This study aimed to investigate the similarities in the gut microbiota among patients with CD, NCWS, and IBS in comparison to healthy controls (HC). MATERIALS AND METHODS: In this prospective study, in total 72 adult subjects, including CD (n = 15), NCWS (n = 12), IBS (n = 30), and HC (n = 15) were recruited. Fecal samples were collected from each individual. A quantitative real-time PCR (qPCR) test using 16S ribosomal RNA was conducted on stool samples to assess the relative abundance of Firmicutes, Bacteroidetes, Bifidobacterium spp., and Lactobacillus spp. RESULTS: In all groups, Firmicutes and Lactobacillus spp. had the highest and lowest relative abundance respectively. The phylum Firmicutes had a higher relative abundance in CD patients than other groups. On the other hand, the phylum Bacteroidetes had the highest relative abundance among healthy subjects but the lowest in patients with NCWS. The relative abundance of Bifidobacterium spp. was lower in subjects with CD (P = 0.035) and IBS (P = 0.001) compared to the HCs. Also, the alteration of Firmicutes to Bacteroidetes ratio (F/B ratio) was statistically significant in NCWS and CD patients compared to the HCs (P = 0.05). CONCLUSION: The principal coordinate analysis (PCoA), as a powerful multivariate analysis, suggested that the investigated gut microbial profile of patients with IBS and NCWS share more similarities to the HCs. In contrast, patients with CD had the most dissimilarity compared to the other groups in the context of the studied gut microbiota. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12876-023-02649-y.