Ref | Study design | Participants | Intervention versus control/comparator (n) | Duration | Symptom scoring | Findings |
Controlled trials | ||||||
Staudacher et al 49 | Placebo-controlled dietary advice RCT (single blind) | Rome III IBS-D, IBS-M, IBS-U | LFD n=51 Sham diet n=53 | 4 weeks | AR IBS-SSS IBS-QOL | Primary outcome: No difference in AR (LFD 57% vs control 38%; p=0.051) Secondary outcomes: Lower IBS-SSS score (LFD 173 vs control 224; p=0.001) and greater numbers achieving MCID for IBS-QOL (LFD 51% vs control 26%; p<0.023) |
Staudacher et al 50 | Dietary advice RCT (unblind) | Rome III IBS with bloating or diarrhoea | LFD n=19 Habitual diet n=22 | 4 weeks | AR GSRS Bristol Stool Form | Primary outcome: Luminal microbiota (see table 3) Secondary outcomes: Greater numbers reporting AR (LFD 68% vs control 23%; p=0.005) Lower bloating, borborygmi, overall symptoms LFD versus control (p<0.05) Greater number of normal stools (LFD 24% vs control 7%; p=0.02) |
Harvie et al 69 | Dietary advice RCT (unblind) | Rome III IBS | LFD n=23 Waiting list n=27 | 3 months | IBS-SSS IBS-QOL | Outcomes: Greater reduction in IBS-SSS (LFD 276 to 129 pt vs control 247 to 204 pt; p<0.01), frequency of pain episodes (p<0.01) Greater increase in IBS-QOL score for LFD versus control (p<0.0001) |
Pedersen et al 88 | Dietary advice RCT (unblind) | Rome III IBS | LFD n=42 Probiotic n=41 Habitual diet n=40 | 6 weeks | IBS-SSS IBS-QOL | Primary outcome: Greater reduction in IBS-SSS (LFD −75 pt vs control −32 pt; p<0.01) Secondary outcome: No change in IBS-QOL for all groups |
Halmos et al 73 | Placebo-controlled feeding RCT, crossover (single blind) | Rome III IBS | LFD n=27 Typical diet n=27 | 21 days | 100 mm symptom VAS Stool frequency Stool water content | Primary outcome: Lower overall GI symptoms (LFD 23 mm vs control 45 mm; p<0.001). Secondary outcome: Lower stool frequency in IBS-D in LFD versus control |
Comparative trials | ||||||
McIntosh et al 42 | Dietary advice RCT (single blind) | Rome III IBS | LFD n=20 HFD n=20 | 3 weeks | Responder: ≥50 pt reduction IBS-SSS | Primary outcome: area under the curve for lactulose breath test Secondary outcomes: Greater number of responders (LFD 72% vs HFD 21%; p<0.009) Lower IBS-SSS in LFD versus HFD (p=0.01) |
Hustoft et al 48 | Dietary advice RCT, crossover (double blind) | Rome III IBS-D, IBS-M | LFD+placebo n=20 LFD+fructans n=20 | 6 weeks | IBS-SSS 100 mm symptom VAS | Outcomes: Lower IBS-SSS (LFD 80% vs control 30%; p=0.014) and severity of nausea/vomiting, belching, flatulence in LFD versus control (p<0.05) |
Eswaran et al 70 | Dietary advice RCT (unblind) | Rome III IBS-D | LFD=45 Modified NICE guideline n=39 | 4 weeks | Responder: AR ≥50% of weeks 3,4 Composite pain and stool score | Primary outcome: No difference in numbers of responders (LFD 52% vs control 41%; p=0.31) Secondary outcomes: No difference in those achieving composite score endpoint (LFD 27% vs control 13%; p=0.13) Greater reduction in pain (LFD 51% vs control 23%; p=0.008) |
Peters et al 71 | Dietary advice RCT (unblind) | Rome III IBS | LFD n=24 Hypnotherapy n=25 Combined LFD and hypnotherapy n=25 | 6 weeks | Responder: ≥20 mm VAS improvement in symptoms IBS-QOL | Primary outcome: No difference in numbers of responders (LFD 71% vs hypnotherapy 72% vs combination 72%; p=0.67). Secondary outcomes: Lower symptom severity in LFD and hypnotherapy versus baseline (p<0.05) and higher IBS-QOL scores in all groups compared with baseline (p<0.001) but no differences between groups for symptoms or IBS-QOL |
Böhn et al 75 | Dietary advice RCT (single blind) | Rome III IBS | LFD n=38 NICE guideline n=37 | 4 weeks | Responder:≥50 pt reduction IBS-SSS Stool frequency and consistency | Primary outcome: No difference in number of responders (LFD 50% vs control 46%; p=0.72) |
AR, adequate relief; FFQ, Food Frequency Questionnaire; FODMAP, fermentable oligosaccharides, disaccharides, monosaccharides and polyols; FOS, fructo-oligosaccharide; GSRS, Gastrointestinal Symptom Rating Scale; HFD, high FODMAP diet; IBS-QOL, IBS Quality of Life Questionnaire; IBS-SSS, IBS Severity Scoring System; LFD, low FODMAP diet; MCID, minimal clinically important difference; NICE, National institute for Health and Care Excellence; RCT, randomised controlled trial; VAS, visual analogue scale.