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

Abstract

Background Irritable bowel syndrome (IBS) and other functional bowel disorders (FBDs) are prevalent disorders with altered microbiota. Prebiotics positively augment gut microbiota and may offer therapeutic potential. Objectives The aim of this study was to investigate the effect of prebiotics compared with 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 FBDs. Methods 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 FBDs were included. Two reviewers independently performed screening, data extraction, and bias assessment. Outcome data were synthesized as ORs, weighted mean differences (WMDs) or standardized mean differences (SMDs) with the use of a random-effects model. Subanalyses were performed for type of FBD and dose, type, and duration of prebiotic. Results Searches identified 2332 records, and 11 RCTs were eligible (729 patients). The numbers responding were 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 QoL 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 of the 16S ribosomal RNA gene; 95% CI: 0.06, 2.26; P = 0.04). No studies were at low risk of bias across all bias categories. Conclusions Prebiotics do not improve gastrointestinal symptoms or QoL in patients with IBS or other FBDs, but they do increase bifidobacteria. Variations in prebiotic type and dose impacted symptom improvement or exacerbation. This review was registered at PROSPERO as CRD42017074072.

Food supplements and diet as treatment options in irritable bowel syndrome

“…However, sensitivity analyses revealed that prebiotic doses of ≤6 g/d improved flatulence (SMD 0.35, 95% CI −0.71‐0.00, P = .005), whereas higher doses did not. Flatulence was significantly exacerbated with inulin‐type fructans (SMD 0.85, 95% CI 0.23‐1.47, P = .007), but was improved with non‐inulin‐type fructans (SMD −0.34, 95% CI −0.66 to −0.01, P = .04) 36 . These findings highlight the importance of considering both the type and the doses of prebiotics in clinical practice and research.…”

“…With the gut microbiota suggested to contribute to the pathophysiology of IBS, studies have also investigated the impact of prebiotic fibers, which are “selectively utilized by host microorganisms conferring a health benefit” 35 . A recent systematic review and meta‐analysis of 11 RCTs in 729 patients with IBS and other functional bowel disorders showed that although prebiotics increased bifidobacteria compared to placebo (mean difference 1.16 log10 rRNA copies, 95% CI 0.06‐2.26, P = .004), there were no differences in response to treatment, abdominal pain, bloating, and flatulence 36 . However, sensitivity analyses revealed that prebiotic doses of ≤6 g/d improved flatulence (SMD 0.35, 95% CI −0.71‐0.00, P = .005), whereas higher doses did not.…”

Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults

“…In contrast, an improvement in symptoms with FOS was reported in a more recent RCT, in which 105 patients diagnosed with minor Functional Bowel Disorders were randomized into two groups to receive either 5 g/day of short-chain FOS or 5 g of a placebo (sucrose and maltodextrins) over a 6-week period [122]. Despite these data, evidence of prebiotic effectiveness in adult IBS patients is still controversial, as reported in a recent systematic review and meta-analysis of randomized controlled trials, in which the prebiotic type and dose significantly influenced symptom improvement and exacerbation [123]. As a matter of fact, there is some evidence that higher doses may have a negative effect on symptoms [120,121,[124][125][126].…”

The Evolving Role of Gut Microbiota in the Management of Irritable Bowel Syndrome: An Overview of the Current Knowledge

“…Indeed, several clinical studies have examined prebiotics' performance in ameliorating symptoms of functional bowel disorders. A handful of RCTs evaluating the efficacy and safety of prebiotics in IBS [67,68] have been performed. In 1999, a small, double-blind crossover trial of oligofructose published by Hunter and colleagues [69] showed no therapeutic value in IBS patients.…”