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OBJECTIVES: Industrialization has increased chronic disease prevalence, potentially due to lifestyle-induced disruptions of the gut microbiome. Decreased intake of dietary fibers is likely a key factor as they play an important role in chronic disease prevention and are growth substrates for the gut microbiota. Strategies that restore microbiome diversity, such as reintroducing health-promoting bacterial species and microbiota accessible carbohydrates (MACs), have been proposed to improve health but have not yet been systematically tested. The objective of this study was to determine the effects of a microbiome restoration strategy on metabolic markers in healthy adults. METHODS: Using a randomized controlled pilot study, 30 subjects consumed either a MAC-rich diet or their usual diet for three weeks each in a crossover fashion, with a three-week washout following each diet period. Participants were further divided into three groups and consumed either a single dose of one of two Limosilactobacillus reuteri strains, a rare species in industrialized microbiomes, or a placebo on day four of each diet period. Metabolic markers (standard lipid panel, glucose, insulin, C-reactive protein (CRP)) were assessed in blood collected at the start and end of each diet period. Data were analyzed using repeated measures ANOVA. RESULTS: Compared to baseline, the MAC-rich diet induced substantial metabolic changes, as it reduced total cholesterol (P

Background Variability in the health effects of dietary fiber might arise from inter-individual differences in the gut microbiota’s ability to ferment these substrates into beneficial metabolites. Our understanding of what drives this individuality is vastly incomplete and will require an ecological perspective as microbiomes function as complex inter-connected communities. Here, we performed a parallel two-arm, exploratory randomized controlled trial in 31 adults with overweight and class-I obesity to characterize the effects of long-chain, complex arabinoxylan (n = 15) at high supplementation doses (female: 25 g/day; male: 35 g/day) on gut microbiota composition and short-chain fatty acid production as compared to microcrystalline cellulose (n = 16, non-fermentable control), and integrated the findings using an ecological framework. Results Arabinoxylan resulted in a global shift in fecal bacterial community composition, reduced α-diversity, and the promotion of specific taxa, including operational taxonomic units related to Bifidobacterium longum, Blautia obeum, and Prevotella copri. Arabinoxylan further increased fecal propionate concentrations (p = 0.012, Friedman’s test), an effect that showed two distinct groupings of temporal responses in participants. The two groups showed differences in compositional shifts of the microbiota (p ≤ 0.025, PERMANOVA), and multiple linear regression (MLR) analyses revealed that the propionate response was predictable through shifts and, to a lesser degree, baseline composition of the microbiota. Principal components (PCs) derived from community data were better predictors in MLR models as compared to single taxa, indicating that arabinoxylan fermentation is the result of multi-species interactions within microbiomes. Conclusion This study showed that long-chain arabinoxylan modulates both microbiota composition and the output of health-relevant SCFAs, providing information for a more targeted application of this fiber. Variation in propionate production was linked to both compositional shifts and baseline composition, with PCs derived from shifts of the global microbial community showing the strongest associations. These findings constitute a proof-of-concept for the merit of an ecological framework that considers features of the wider gut microbial community for the prediction of metabolic outcomes of dietary fiber fermentation. This provides a basis to personalize the use of dietary fiber in nutritional application and to stratify human populations by relevant gut microbiota features to account for the inconsistent health effects in human intervention studies. Trial registration Clinicaltrials.gov, NCT02322112, registered on July 3, 2015.

AIM: To identify demographic, clinical, metabolomic, and lifestyle related predictors of relapse in adult ulcerative colitis (UC) patients.METHODS: In this prospective pilot study, UC patients in clinical remission were recruited and followed-up at 12 mo to assess a clinical relapse, or not. At baseline information on demographic and clinical parameters was collected. Serum and urine samples were collected for analysis of metabolomic assays using a combined direct infusion/liquid chromatography tandem mass spectrometry and nuclear magnetic resolution spectroscopy. Stool samples were also collected to measure fecal calprotectin (FCP). Dietary assessment was performed using a validated self-administered food frequency questionnaire.RESULTS: Twenty patients were included (mean age: 42.7 ± 14.8 years, females: 55%). Seven patients (35%) experienced a clinical relapse during the follow-up period. While 6 patients (66.7%) with normal body weight developed a clinical relapse, 1 UC patient (9.1%) who was overweight/obese relapsed during the follow-up (P= 0.02). At baseline, poultry intake was significantly higher in patients who were still in remission during follow-up (0.9 ozvs0.2 oz,P= 0.002). Five patients (71.4%) with FCP > 150 μg/g and 2 patients (15.4%) with normal FCP (≤ 150 μg/g) at baseline relapsed during the follow-up (P= 0.02). Interestingly, baseline urinary and serum metabolomic profiling of UC patients with or without clinical relapse within 12 mo showed a significant difference. The most important metabolites that were responsible for this discrimination were trans-aconitate, cystine and acetamide in urine, and 3-hydroxybutyrate, acetoacetate and acetone in serum.CONCLUSION: A combination of baseline dietary intake, fecal calprotectin, and metabolomic factors are associated with risk of UC clinical relapse within 12 mo.