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Prebiotics in irritable bowel syndrome and other functional bowel disorders in adults: a systematic review and meta-analysis of randomized controlled trials

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)1098-1111
Number of pages14
JournalThe American journal of clinical nutrition
Issue number4
Early online date4 Apr 2019
Publication statusPublished - 4 Apr 2019


King's Authors


Irritable bowel syndrome (IBS) and other functional bowel disorders (FBD) are prevalent disorders with altered microbiota. Prebiotics positively augment gut microbiota and may offer therapeutic potential.
To investigate the effect of prebiotics compared to placebo on global response, gastrointestinal symptoms, quality of life (QoL) and gut microbiota, via systematic review and meta-analysis of randomized controlled trials (RCTs) in adults with IBS and other FBD.
Studies were identified using electronic databases, back-searching reference lists and hand-searching abstracts. RCTs that compared prebiotics to placebo in adults with IBS or other FBD were included. Two reviewers independently performed screening, data extraction, and bias assessment. Outcome data were synthesized using odd ratios (OR), weighted mean differences (WMD) or standardized mean differences (SMD) using a random-effects model. Sub-analyses were performed for type of FBD and dose, type and duration of prebiotic.
Searches identified 2332 records, and 11 RCTs were eligible (729 patients). Response to intervention was 52/97 (54%) for prebiotic and 59/94 (63%) for placebo, with no difference between groups (OR 0.62; 95%CI 0.07, 5.69; p=0.67). Similarly, no differences were found for severity of abdominal pain, bloating and flatulence, and quality of life score between prebiotics and placebo. However, flatulence severity was improved by prebiotics at doses ≤6 g/d (SMD -0.35, 95%CI -0.71, 0.00, p=0.05) and by non-inulin type fructan prebiotics (SMD -0.34, 95%CI -0.66, -0.01, p=0.04), while inulin-type fructans worsened flatulence (SMD 0.85, 95%CI 0.23, 1.47, p=0.007). Prebiotics increased absolute abundance of bifidobacteria (WMD 1.16 log10 copies 16S rRNA gene; 95%CI 0.06, 2.26; p=0.04). No studies were at low risk of bias across all bias categories.
Prebiotics do not improve gastrointestinal symptoms or quality of life in patients with IBS or other FBD, but they do increase bifidobacteria. Variations in prebiotic type and dose impacted symptom improvement or exacerbation.
Keywords: Prebiotics, IBS, FBD, inulin type fructans, galactooligosaccharides 

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