Table 1.
Characteristics of experimental studies included in the meta-analysis
| First author, year (country) | Study duration | Total case/controlsa | Type of treatment: intervention vs. control | Age (years)b | Female (%)b | Predominant IBS subtype (%)b | Results |
|---|---|---|---|---|---|---|---|
| Bohn, 2015 [63] (Sweden) | 4 weeks | 33/34 | Dietary education: LFD vs. traditional IBS diet (NICE and BDA) | 42.5 | 81.3 | IBS-M (47) | No significant difference in IBS-SSS was observed between the LFD and control group (246 vs. 23, P = 0.62) |
| Eswaran, 2016 [70] (USA) | 4 weeks | 43/39 | Dietary education: LFD vs. traditional IBS diet (NICE) | 42.6 | 70.7 | IBS-D (100) | The mean abdominal pain score decreased to 3.4 in the LFD group vs. 4.4 in the mNICE group (P = 0.005), and the IBS- QoL score increased to 69.3 for the LFD group vs. 59.4 for the mNICE group (P value not reported) |
| Halmos, 2014 [61] (Australia) | 42 days | 30/30 | Provided diets: LFD vs. typical Australian diet (4.4 g oligosaccharides and 2.6 g polyols/day) | 41.0 | 71.1 | IBS-C (43) | Subjects reported lower mean VAS-scores (0–100) for GI symptoms when on an LFD compared to control: 22.8 vs. 44.9 (P < 0.001) |
| Harvie, 2017 [52] (New Zealand) | 3 months | 23/27 | Dietary education on LFD vs. no dietary education | 41.8 | 86 | IBS-D (64) | Subjects on the LFD had a lower mean IBS-SSS (128 vs. 206) and higher mean IBS-QoL (81 vs. 73) compared to control, after 3 months (P < 0.05 in both for improvement) |
| McIntosh, 2017 [64] (Canada) | 21 days | 18/19 | Dietary education: LFD vs. HFD | 50.9 | 86.5 | IBS-M (62) | Mean IBS-SSS decreased to 208 in the LFD group vs. 290 in the control group (P = 0.01) |
| Ong, 2010 [40] (Australia) | 4 days | 15/15 | Provided diets: LFD (9 g FODMAPs/day) vs. HFD (50 g/day) | 40.8 | 73.3 | IBS-C (47) | IBS symptom severity assessed by a self-rating Likert scale was reported to be lower during the LFD (median 2; range 0–7) than during HFD (6; 2–9) |
| Paduano, 2019 [53] (Italy) | 12 weeks | 34/28 | Dietary education: LFD vs. balanced Mediterranean diet | 28.6 | 83.3 | IBS-D (52) | No significant differences were found between the LFD and control diet when looking at mean IBS-SSS (16 vs. 17, P = 0.44) and IBS-QoL (83 vs. 81, P = 0.27) |
| Patcharatrakul, 2019 [62] (Thailand) | 4 weeks | 30/32 | Dietary education: personalized LFD vs. commonly recommended diet to reduce IBS symptoms | 51.0 | 75.8 | IBS-C (53) | The mean global IBS symptom severity score (VAS 0–100) after intervention was lower in the LFD group than the control group (38.5 ± 20 vs. 53.5 ± 19, P < 0.01) |
| Pedersen, 2014 [41] (Denmark) | 6 weeks | 42/40 | Dietary education: LFD including personalized reintroduction vs. unchanged Danish/Western diet | 34.6 | 76.8 | IBS-D (45) | There was a significantly greater reduction in mean IBS-SSS in the LFD group than in the control group (133 vs. 34, P < 0.01). Mean IBS-QoL was not altered significantly (LFD: 8 vs. control: 0.1, P = 0.13) |
| Staudacher, 2012 [66] (UK) | 4 weeks | 16/19 | Dietary education: LFD vs. habitual diet | 35.1 | 35.1 | NR | The mean overall symptom severity score (0–3 scale) after intervention was lower in the LFD group than in the control group (1.1 vs. 1.7, P < 0.002) |
| Staudacher, 2017 [69] (UK) | 4 weeks | 51/53 | Dietary education: LFD vs. sham exclusion diet (comparable in number of restricted foods and difficulty) | 34.4 | 68.6 | IBS-D (67) | Mean IBS-SSS was significantly lower for patients on the LFD than the sham diet (173 vs. 224, P = 0.001). No significant difference was observed between the groups for IBS-QoL (72.4 vs. 70.6, P = 0.057) |
| Zahedi, 2018 [42] (Iran) | 6 weeks | 50/51 | Dietary education: LFD (< 0.5 g of FODMAPs per meal) vs. traditional IBS diet (BDA) | 37.5 | 50.5 | IBS-D (100) | Mean IBS-SSS decreased to a greater extent in the LFD group compared to control (108 vs. 149.8, P = 0.002). No significant difference was observed between the groups for IBS-QOL (− 7.3 vs. − 5.35, P = 0.332) |
The data are represented as mean value unless indicated otherwise
BDA British Dietetic Association; FODMAP fermentable oligo-, di-, monosaccharides and polyols; HFD high-FODMAP diet; IBS-C irritable bowel syndrome with constipation; IBS-D irritable bowel syndrome with diarrhea; IBS-M irritable bowel syndrome with mixed stool pattern; IBS-QoL irritable bowel syndrome-associated quality of life; IBS-SSS irritable bowel syndrome severity scoring system; LFD low-FODMAP diet; NICE National Institute for Health and Care Excellence; NR not reported
aNumbers are retrieved from per-protocol data
bNumbers are retrieved from intention-to-treat data