title: Effects of varying dietary content of fermentable short-chain carbohydrates on symptoms, fecal microenvironment, and cytokine profiles in patients with irritable bowel syndrome.
abstract: BACKGROUND
  A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is increasingly recommended for patients with irritable bowel syndrome (IBS). We aimed to investigate the effects of a blinded low-FODMAP vs high-fructo-oligosaccharides (FOS) diet on symptoms, immune activation, gut microbiota composition, and short-chain fatty acids (SCFAs).
  
  
  METHODS
  Twenty patients with diarrhea-predominant or mixed IBS were instructed to follow a low-FODMAP diet (LFD) throughout a 9-week study period. After 3 weeks, they were randomized and double-blindly assigned to receive a supplement of either FOS (FODMAP) or maltodextrin (placebo) for the next 10 days, followed by a 3-week washout period before crossover. Irritable bowel syndrome severity scoring system (IBS-SSS) was used to evaluate symptoms. Cytokines (interleukin [IL]-6, IL-8, and tumor necrosis factor alpha) were analyzed in blood samples, and gut microbiota composition (16S rRNA) and SCFAs were analyzed in fecal samples.
  
  
  RESULTS
  Irritable bowel syndrome symptoms consistently improved after 3 weeks of LFD, and significantly more participants reported symptom relief in response to placebo (80%) than FOS (30%). Serum levels of proinflammatory IL-6 and IL-8, as well as levels of fecal bacteria (Actinobacteria, Bifidobacterium, and Faecalibacterium prausnitzii), total SCFAs, and n-butyric acid, decreased significantly on the LFD as compared to baseline. Ten days of FOS supplementation increased the level of these bacteria, whereas levels of cytokines and SCFAs remained unchanged.
  
  
  CONCLUSIONS
  Our findings support the efficacy of a LFD in alleviating IBS symptoms, and show changes in inflammatory cytokines, microbiota profile, and SCFAs, which may have consequences for gut health.
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: T N
authors.initials: TN
authors.lastname: Hustoft
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Section of Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway.|National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, Bergen, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Hausken
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.|National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, Bergen, Norway.
authors.forename: S O
authors.initials: SO
authors.lastname: Ystad
authors.affiliation: Unger-Vetlesen's Institute, Lovisenberg Diaconal Hospital, Oslo, Norway.
authors.forename: J
authors.initials: J
authors.lastname: Valeur
authors.affiliation: Department of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Brokstad
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Section of Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway.|National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, Bergen, Norway.
authors.forename: J G
authors.initials: JG
authors.lastname: Hatlebakk
authors.affiliation: Department of Clinical Medicine, University of Bergen, Bergen, Norway.|Section of Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway.|National Centre of Functional Gastrointestinal Disorders, Haukeland University Hospital, Bergen, Norway.
authors.forename: G A
authors.initials: GA
authors.lastname: Lied
mesh_terms: D000293:Adolescent; D000328:Adult; D060833:Cellular Microenvironment / Q000187:drug effects / Q000502:physiology; D018592:Cross-Over Studies; D016207:Cytokines / Q000097:blood*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004311:Double-Blind Method; D005232:Fatty Acids, Volatile / Q000008:administration & dosage; D005243:Feces / Q000382:microbiology; D005260:Female; D000074421:Fermented Foods; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000097:blood* / Q000175:diagnosis / Q000178:diet therapy*; D008297:Male; D008875:Middle Aged; D009844:Oligosaccharides / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D016207:Cytokines; D004040:Dietary Carbohydrates; D005232:Fatty Acids, Volatile; D009844:Oligosaccharides
keywords: FODMAPs; gut microbiota; irritable bowel syndrome; proinflammatory cytokines; short-chain fatty acids