Influence of low FODMAP-gluten free diet on gut microbiota alterations and symptom severity in Iranian patients with irritable bowel syndrome

• Published in: BMC gastroenterology Vol. 21; no. 1; pp. 292 - 14
• Main Authors: Naseri, Kaveh, Dabiri, Hossein, Rostami-Nejad, Mohammad, Yadegar, Abbas, Houri, Hamidreza, Olfatifar, Meysam, Sadeghi, Amir, Saadati, Saeede, Ciacci, Carolina, Iovino, Paola, Zali, Mohammad Reza
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 14.07.2021; BioMed Central; BMC
• Subjects: Adult; Antibiotics; Bacteroidetes; Carbohydrates; Clinical trials; Defecation; Development and progression; Diet; Diet therapy; Diet, Gluten-Free; Dietary restrictions; Dietitians; Digestive organs; Digestive system; Dysbacteriosis; Enzyme-linked immunosorbent assay; Feces; Fermentation; Food; Gastroenterology; Gastrointestinal Microbiome; Gastrointestinal tract; Genetic testing; Gluten; Gluten-free diet; Gut microbiota; Health aspects; Humans; IBS-SSS; Inflammation; Intervention; Intestinal microflora; Intestine; Iran; Irritable Bowel Syndrome; Liver diseases; Low-carbohydrate diet; Low-FODMAP; Methods; Microbiota; Microbiota (Symbiotic organisms); Middle Aged; Nutrient deficiency; Nutrition research; Nutritionists; Pathogenesis; Patients; Physiological aspects; Probiotics; rRNA; Iran; United States > US; Gut microbiota; Low-FODMAP; Gluten-free diet; Iran; IBS-SSS; Irritable bowel syndrome
• ISSN: 1471-230X; 1471-230X
• DOI: 10.1186/s12876-021-01868-5

Recently, dietary restriction of fermentable carbohydrates (a low-FODMAP diet) in combination with a gluten-free diet (GFD) has been proposed to reduce the symptoms in irritable bowel syndrome (IBS) patients. Different studies reported that IBS has been associated with dysbiosis in the gut microbiota. Additionally, a few studies have reported inflammation in the gastrointestinal (GI) system of adults with IBS. In this study, we aimed to investigate the effects of low FODMAP-gluten free diet (LF-GFD) on clinical symptoms, intestinal microbiota diversity, and fecal calprotectin (FC) level in Iranian patients with IBS. In this clinical trial study, 42 patients with IBS (Rome IV criteria) underwent LF-GFD intervention for 6 weeks. Symptoms were assessed using the IBS symptom severity scoring (IBS-SSS), and fecal samples were collected at baseline and after intervention and analyzed by quantitative 16 S rRNA PCR assay. The diversity of gut microbiota compared before and after 6 weeks of dietary intervention. FC was also analyzed by the ELISA method. Thirty patients (mean age 37.8 ± 10.7 years) completed the 6-week diet. The IBS-SSS was significantly (P = 0.001) reduced after LF-GFD intervention compared to the baseline. Significant microbial differences before and after intervention were noticed in fecal samples. A significant increase was found in Bacteroidetes, and the Firmicutes to Bacteroidetes (F/B) ratio was significantly (P = 0.001) decreased after the dietary intervention. The value of FC was significantly decreased after 6 weeks of dietary intervention (P = 0.001). Our study suggests that patients with IBS under an LF-GFD had a significant improvement in IBS symptoms severity, with reduced FC level following normalization of their gut microbiota composition. Further rigorous trials are needed to establish a long-term efficacy and safety of this dietary intervention for personalized nutrition in IBS. Clinical Trial Registry Number: IRCT20100524004010N26.