Changes in gut microbial metagenomic pathways associated with clinical outcomes after the elimination of malabsorbed sugars in an IBS cohort

Abstract

Specific diets to manage sugar malabsorption are reported to reduce clinical symptoms of irritable bowel syndrome (IBS). However, the effects of diets for malabsorbed sugars on gut microbiota signatures have not been studied, and associations with clinical outcomes in IBS have not been characterized. 22 IBS patients positively tested for either lactose-, fructose-, sorbitol-or combined malabsorptions were subjected to 2-weeks sugar elimination and subsequent 4-weeks reintroduction. 7 IBS patients tested negative for sugar malabsorption were used as controls. Nutrition and clinical symptoms were recorded throughout the study. Fecal samples were serially collected for 16S rRNA amplicon and shotgun-metagenome sequencing. Dietary intervention supervised by nutrition counseling reduced IBS symptoms during the elimination and tolerance phases. Varying clinical response rates were observed between subjects, and used to dichotomize our cohort into visual analogue scale (VAS) responders and nonresponders. Alpha-and beta-diversity analyzes revealed only minor differences regarding 16S rRNA-based fecal microbiota compositions between responder and non-responder patients during baseline or tolerance phase. In shotgun-metagenome analyzes, however, we analyzed microbial metabolic pathways and found significant differences in pathways encoding starch degradation and complex amino acid biosynthesis at baseline between IBS controls and malabsorbers, and notably, between diet responder and non-responders. Faecalibacterium prausnitzii, Ruminococcus spp. and Bifidobacterium longum largely informed these metabolic pathways. Our study demonstrates that diet interventions for specific, malabsorbed carbohydrates reshaped the metagenomic composition of the gut microbiota, with a small community of bacterial taxa contributing to these changes rather than a single species.

Comparison of the Gut Microbiota Disturbance in Rat Models of Irritable Bowel Syndrome Induced by Maternal Separation and Multiple Early-Life Adversity

“…Furthermore, Ruminococcus spp. were less abundant in IBS patients relative to controls in another study ( Mack et al., 2019 ). Moreover, several studies have shown that the abundances of Butyricicoccus were lower in ulcerative colitis patients and patients with inflammatory disease in general ( Eeckhaut et al., 2013 ; Rios-Covian et al., 2016 ; Devriese et al., 2017 ).…”

Assessment of a 4-Week Starch- and Sucrose-Reduced Diet and Its Effects on Gastrointestinal Symptoms and Inflammatory Parameters among Patients with Irritable Bowel Syndrome

“…Dietary manipulation could affect the microbiota and improve SIBO [ 38 , 39 ]. A previous report demonstrated that dietary interventions for specific, malabsorbed carbohydrates influenced the composition of the gut microbiota [ 11 ].…”

“…Unabsorbed carbohydrates may induce digestive symptoms through colonic fermentation or osmotic activity, resulting in bloating, flatulence, abdominal pain, and diarrhea [ 3 , 5 ]. Historically, clinical investigation of IBS patients has focused on identifying fructose and/or lactose intolerance, conditions identified in up to 70% of IBS patients [ 11 ]. In a recent study by Kim et al [ 12 ], SI deficiency (SID) was identified through intestinal biopsy in 35% of patients with presumed IBS-D/M.…”

Metagenomic analysis identified microbiome alterations and pathological association between intestinal microbiota and polycystic ovary syndrome

“…Although 16S rRNA sequencing allows reliable taxa resolution up to the genus level, it has not provided information about the functional characteristics. Shotgun metagenome studies go far beyond conventional 16S rRNA microbiome sequencing, and add a functional component to the microbiome analysis (24,25). Thus, we used multiomics technologies to explore the taxonomic structure of specific strains and identify the microbial function and metabolic mechanisms of strain-specific involvement in the developmental progress of PCOS.…”