Table 2.
Main results of the systematic review.
| Author | Study | n/Age | Disease | P/m | CC | Treatment | Variables | Main Results |
|---|---|---|---|---|---|---|---|---|
| Heaton et al., 1979 [37] | CCS | 64/36 M 31 F 33 |
CD UCFR/ND 32/32 |
52 | GBR | UCFR and ND | Admission to hospital, IOP, EIMs | The number of hospital admissions required in UCFR patients was 11 compared with 34 in the ND (p < 0.01). UCFR patients spent a total of 111 days in hospitals compared with 533 days for ND (p < 0.005). Intestinal operations were performed on only one UCFR patient but on five ND. |
| Berghouse et al., 1984 [38] | RCCT | 10/44 M 6 F 4 |
SUR IBD CD/UC 5/5 |
0.5 | GBR | UCRF and RCD | 7-FR, chemical analysis of the ileostomy fluid | Compliance with the dietary advice was good. A dietary assessment was possible in 7/10 patients. The amount of ileostomy effluent was significantly greater on the UCRF both in terms of wet weight (238 ± 89 g vs. 162 ± 79 g) and dry weight (23.6 ± 6.8 g vs. 14−9 ± 6−6 g). |
| Jones et al., 1985 [39] | RCCT | 20/30.73 M 18 F 2 |
ACT CD EG/CG 10/10 |
6 | GBR | EG: SFID CG: UCFR |
CDAI, ESR, length of remission, orosomucoid | At 6 months, 7 patients on an SFID remained well (p < 0.05, Fisher´s exact test). The mean time to relapse was 1.38 ± 1.74 (SD) months in the UCFR group and 2.75 ± 1.98 months in the SFID group. For patients on the SFID who remained in remission for 6 months, the ESR (mean ± SD) dropped from 39.7 ± 21.7 mm/h before the trial to 16.2 ± 12.5 (p < 0.05) at 6 months and their orosomucoid concentrations dropped from 232.5 ± 68.2% before the trial to 140 ± 41.5% (p < 0.05) at 6 months. |
| Ritchie et al., 1987 [40] | RCCT | 352/35.4 M 130 F 222 |
REM CD RCD/UCFR 162/190 |
24 | GBR | UCFR and RCD | RC, clinical deterioration, 7-FR, BW | 178 patients completed the trial. The cumulative proportion of patients remaining in the trial without deterioration of the disease was 64% in RCD and 59% in UCFR. The clinical score, stool count, and BW showed no significant changes with either diet. |
| Lomer et al., 2001 [41] | RCCT | 20/36.2 M 3 F 17 |
ACT CD LMD/NMD 10/10 |
4 | GBR | LMD and NMD | CDAI, HEMA, CA, and ALB | Despite a higher CDAI at month 0 in the LMD group, compared to the NMD group, there was a significantly lower CDAI in the LMD group by month 4 (145 ± 47 vs. 295 ± 25). All patients had normal CA levels, corrected for ALB, and there were no significant changes in nutritional status in either group. |
| Lomer et al., 2005 [42] | RCCT | 83/36 M 40 F 43 |
ACT-CD LCLM/LCNM/ NCLM/NCNM 22/21/ 20/20 |
4 | GBR | LCLM, LCNM, NCLM and NCNM | CDAI, VHI, IBDQ, ESR, CRP, FC, IP | No differences were found between the low and normal calcium groups for CDAI, VHI, IBDQ, CRP, ESR, FC, or IP, neither between the low and normal dietary calcium groups nor between the low and normal microparticle groups. |
| Croagh et al., 2007 [43] | CS and RCS | 15/43.6 M 6 F 9 |
SUR IBD CS/ RCS 8/7 |
1.5 | AUS | LFD | FL, SF, DH, adherence to diet | In the RCS, adherence was good in 5/7 patients, while in the CS, it was 3/8; 5/7 studied retrospectively improved stool frequency (from median 8 to 4 per day; p < 0.05). In CS, only 5 patients were evaluable for the effect of diet on SF, with no change seen. For the 7 patients without pouchitis, median daily SF fell from 8 to 4 (p < 0.001). |
| Gearry et al., 2008 [44] | CSS | 72/48 M 33 F 39 |
REM CD/UC 52/20 |
3 | AUS | LFD | Adherence to diet, change of gastrointestinal symptoms | Overall abdominal symptoms, abdominal pain, bloating, wind, and diarrhea improved in patients with CD and UC (p < 0.02 for all), but constipation did not. The median response for LFD implementation was 3/10 “easy” (SD 2.9, range 0–10, interquartile range 0.25–5). |
| Benz et al., 2010 [45] | RCCT | 40/41 M 16 F 24 |
ACT CD IGED/CG 20/20 |
1.5 | GER | IGED and CG (Sham diet) | GISD, SF. and general well-being | An average reduction in the total weekly score of 6.5 points was estimated for the IGED group compared with the CG (95% CI: −0.6, 13.6 points). The estimated effect seems to have a clinically relevant effect but is not significant (p = 0.07). The daily SF significantly decreased by 11% during an IGED compared with CG. |
| Chiba et al., 2010 [46] | UNRCT CS |
22/26.5 M 14 F 8 |
ACT CD |
UNRCT 1.5 CS 24 |
JPN | SVD | CDAI, CRP, BMI, ALB, CHOL, CHE, HEM, morphological studies, FFQ | Among the 16 (73%) patients who continued with the SVD, 15 maintained remission and one relapsed; the remission rate was 100% at 1 year and 92% at 2 years. The cumulative relapse rate at 2 years was significantly lower in the SVD group than in the omnivorous group. The concentration of CRP was normal at the final visit in more than half of the patients in remission on an SVD. |
| Rajendran et al., 2010 [47] | UNRCT | 29/39.3 M 18 F 2 |
REM CD |
1 | GBR | IGED | MCDAI, ESR, CRP, ALB | The mean mCDAI score on entry to the trial was 171 ± 108, and after IGED, the mCDAI decreased to 97.5 ± 87 (p < 0.05). The general “well-being” rating improved from 0.88 to 0.63 (p < 0.05). The mean ESR fell from 22.3 ± 16.0 to 17.1 ± 15.2 (p = 0.032). CRP and ALB levels did not change significantly. |
| Uzunismail et al., 2011 [48] | NRCCT | 8/40 M 1 F 7 |
REM CD |
0.5 | TUR | IGED and modifications IGED (provocation periods) | FC, CRP, ESR, WBC, PL, HBI, CDAI | The mean CDAI score before the provocation was 63 ± 29.9 and increased statistically significant to 99.75 ± 46.1 (46–183) during provocation. The HBI score, WBC, CRP, and WBC also increased significantly. |
| Marlow et al., 2013 [49] | UNRCT | 8/45,4 M 2 F 6 |
ACT CD |
1.5 | NZL | MIAID | CRP, DNA damage, and microbiota | Subjects self-reported good adherence to diet; cholesterol levels were reduced by 20%. CRP and micronuclei numbers showed a trend of reduction after the 6-week diet; however, this was not significant. |
| Herfarth et al., 2014 [50] | CSS | 1647/46.35 M 429 F 1218 |
REM IBD GFD/Non-GFD 314/1333 |
14 | USA | GFD | GFDQ | In the GFD group, 206 (65.6%) reported that they experienced an improvement of at least 1 specific clinical symptom, which has been associated with gluten exposure; 38.3% also recounted fewer and less severe flares while being on a GFD, and 23.6% stated that they required fewer medications to control the disease. Excellent adherence was associated with significant improvement of fatigue. |
| Kyaw et al., 2014 [51] | RCCT | 112/ < 65 M 62 F 50 |
UC DMF-UC/ND 61/51 |
6 | GBR | DMF-UC and ND | IBDQ-UK, SCCAI, FFQ | The mean difference between SCCAI at week 0 and week 24 was a reduction by 1.304 (p = 0.0108) in the DMF-UC group. For the ND group, there was an increase in the mean differences between SCCAI at week 0 and week 32 of 0.875 (p = 0.0249). There were no significant differences in the IBDQ score; 69% of patients in the DMF-UC group found the dietary advice significantly or moderately helpful. |
| Gunasekeera et al., 2016 [52] | RCCT | 76/39 M 32 F 44 |
REM CD IGED/CG 39/37 |
1 | GBR | IGED and CG | SIBDQ, CDAI, HBI, CRP, FC | There was a 3.05 (0.01–6.11), p < 0.05, improvement in SIBDQ and 41 (10.4–71.5) in CDAI, p = 0.009. There was no significant difference in FC and CRP levels. |
| Halmos et al., 2016 [53] | RCCT | 9/35 M 3 F 6 |
REM CD |
0.75 | AUS | LFD, TAD and ND | FM, fecal pH, FSCFA, VAS (symptoms), FWC, FC | FC was also similar across the three phases of the study, but in 3 subjects, it was consistently >150 μg/g. Dietary adherence during the interventional diets was good. The severity of overall gastrointestinal symptoms was significantly less on the last 14 days of the LFD at mean 13.5 mm compared with the last 14 days of the TAD at 24.8 mm |
| Maagard et al., 2016 [54] | CSS | 180/43 M 33 F 147 |
IBD:49 IBS:131 |
16 | DEN | LFD | VAS, FARS, assess satisfaction with LFD, BS, CIBSC, IBS-SSS, IBS-QOL, SIBDQ | The patients experiencing full effectiveness were greater in the IBD group than in the IBS group (42% vs. 29%, p = 0.08). At follow-up, the median IBS-QoL score was 75 (range: 37–145) for the IBS group and 63 (range: 36–126) for the IBD group. For the IBD patients only, the median SIBDQ score was 55; 32% of the IBS group and 37% of the IBD group were on the diet for less than 3 months, while 47% and 50%, respectively, stayed on the diet until follow-up. The overall median IBS-SSS score at follow-up was 211 (range: 16–487). |
| Prince et al., 2016 [55] | RCS | 88/40 M 26 F 62 |
REM IBD |
1.5 | GBR | LFD | SRFGS, GRRS, BS | There was a significant increase in the proportion with satisfactory relief of their FGS following a LFD. Individual symptom severity scores decreased following LFD with the greatest reductions in scores observed for bloating and flatulence, followed by abdominal pain and lethargy. More patients reported normal consistency and normal-frequency stools following the LFD (p < 0.05) |
| Suskind et al., 2016 [56] | CSS | 417/34.9 M 125 F 292 |
IBD | 12 | USA | SCD | Online survey: Disease complications, healthcare management, clinical questions (diagnosis, extent, duration, etc) | The reason for individuals starting the SCD was for avoidance of medication (49%), incomplete improvement with medication (28%), no improvement with medication (9%), and/or side effects or allergies to medication (19%). Overall, symptoms such as abdominal pain, limitations in activities, diarrhea, blood in the stool, and weight loss decreased over time; 4% reported clinical remission prior to the SCD, while 33% reported remission at 2 months after initiation of the SCD, and 42% reported both at 6 and 12 months |
| Komperod et al., 2017 [57] | NRCCT | 12/38.41 M 4 F 8 |
REM CD |
0.5 | NOR | KED and ND | GISD, VAS (symptom intensity), FC | A significant decline in symptom intensity was consistently seen across all seven symptoms when we compared symptoms at week 2 of the ND to symptoms at week 2 of the KED. |
| Konijeti et al., 2017 [58] | UNRCT | 15/44 M 4 F 11 |
ACT CD/UC 9/6 |
2.75 | USA | AIPD | Clinical remission, complications, HBI, PMS, SF, RB, PGA, CRP, FC, ALB, SIBDQ | Clinical remission was achieved at week 6 by 11/15 (73%) study participants (6 CD and 5 UC). Mean total SIBDQ scores significantly improved from 46.5 (SD 12.5) at baseline to 53.3 (SD 10.9) at week 6 and 60.5 (SD 4.8) at week 11. From week 0 to weeks 6 and 11, mean PMS significantly improved from 5.8 (SD 1.2) to 1.2 (SD 2.0) and 1.0 (SD 2.0) for UC and mean HBI significantly improved from 7 (SD 1.5) to 3.6 (SD 2.1) and 3.4 (SD 2.6) for CD. CRP and FC did not significantly change during the study |
| Pedersen et al., 2017 [59] | RCCT | 89/40 M 22 F 67 |
REM IBD LFD/ND 44/45 |
1.5 | DEN | LFD and ND | IBS-SSS, SCCAI, HBI, FC, CRP, SIBDQ, IBS-QOL, FFQ | At 6 weeks, a significantly lower IBS-SSS score was observed in the LFD group (median IBS-SSS 115, IQR 33–169) as compared to the ND group (median IBS-SSS 170, IQR 91–288), p = 0.02. At week 6, a statistically significant improvement in SIBDQ was observed in those on a LFD (median 60, IQR 51–65) when compared to those on a ND (median 50, IQR 39–60). No significant differences were found between the LFD and ND groups with regards to FC and CRP change. |
| Chiba et al., 2018 [60] | CS | 60/39 M 35 F 25 |
REM UC IEC/RC 29/31 |
42 | JPN | PBD | PBDS, relapses, and remissions (improvement) | Of 57 cases, 8 (4/28 IEC and 4/29 RC) relapsed during the follow-up period. Cumulative relapse rates at 1, 2, 3, 4, and 5 years were 2%, 4%, 7%, 19%, and 19%, respectively. Mean time to relapse was 7 years 3 months. There were no differences between groups. Most patients (77%) experienced some improvement. The short- and long-term PBD scores after hospitalization were higher than baseline PBD scores. |
| Jian et al., 2018 [61] | RCCT | 97/38.5 M 50 F 47 |
REM UC IGED/ CG 49/48 |
6 | CHN | IGED and ND | MS, EIMs, BMI, ALB, TRF, PA, IBDQ, MF | MS in the ND group was significantly higher than that in the IGED group (3.52 ± 1.15 vs. 2.41 ± 0.89) and the endoscopic appearance tended to be better in the IGED group at 6 months. After dietary intervention, BMI and ALB were significantly higher in the IGED group than in the ND group (23.88 ± 3.31 vs. 21.50 ± 6.24 kg/m2, respectively, 48.05 ± 6.39 vs. 45.72 ± 5.48 g/L). There were no significant differences in PA, TRF, and IBDQ between the groups. |
| Testa et al., 2018 [62] | NRCCT | 127/34.5 M 57 F 70 |
REM IBD IBS/IBD/CLD 56/30/41 |
3 | ITA | LFD | IBS-SSS, SF-36, 7-FR | In the IBD population, the average IBS-SSS scores were 207 ± 88 SD at T0, 139 ± 50 SD at T1, and 73 ± 45 SD at T3 (p < 0.001), demonstrating a good response to LFD. In most of the SF-36 domains, there was a significant improvement from T0 to T3 for all groups; 8/127 (6.3%) patients revealed poor adherence. |
| Bodini et al., 2019 [63] | RCCT | 55/46 M 24 F 31 |
REM IBD LFD/ND 26/29 |
1.5 | ITA | LFD and ND | CRP, FC, PMS, HBI, IBDQ | After 6 weeks of treatment in the LFD group, in patients with CD, median HBI significantly decreased. A statistically significant decrease was observed in median calprotectin values. A significant increase in median IBDQ was detected. However, there were no significant differences between groups for any parameter. |
| Godny et al., 2019 [64] | CS | 153/46 M 72 F 81 |
SUR UC |
36 | ISR | MED | FFQ, MedDiet, PDAI, CRP, FC PGA | Patients with an inactive disease tended to have a higher MED score compared to those with an active disease, but this difference did not achieve statistical significance (4.7 ± 1.8 vs. 4.3 ± 1.7). The MED score was associated with lower odds for elevated FC (adjusted OR = 0.74 [95% CI 0.56–0.99], p < 0.05). Patients who had highly adhered to MED (MED score ≥ 5) had lower rates of pouchitis than patients with low adherence to the MED (26% vs. 45.4%, log rank test, p = 0.17). |
| Papada et al., 2019 [65] | CSS | 86/39.45 M 45 F 41 |
CD ACT-CD: 41 REM-CD: 45 |
6 | GRE | MED | MedDiet, HBI, IBDQ, BW, BMI FE, HDL, LDL, TG, LDH, SGOT, SGPT, γ-GT, ALP, CRP, IL-6, and IL-10 | Adherence was higher in REM-CD than ACT-CD (26.8 ± 5.0 vs. 30.2 ± 5.8, p = 0.005). Protein intake (p = 0.015) and vitamin C (p = 0.003) levels were individually higher in the REM-CD. In the regression models adjusted for age, sex, BMI, and smoking, HBI showed a highly significant negative linear association with the MedDiet score and IBDQ showed a positive linear association with the MedDiet score. |
| Schreiner et al., 2019 [66] | CSS | 1313/NI M NI F NI |
IBD GFD/VD 57/52 |
VD/GFD 193/33.5 |
SUI | GFD, VD and ND | DQ, clinical characteristics, SF-36 | The authors did not find significant differences in either GFD or VD patient disease activities based on CDAI and MTWAI. VD patients had higher scores on the posttraumatic stress diagnostic scale and poorer mental health. A GFD was associated with lower scores in the physical and mental component survey (SF-36) and higher anxiety and depression scores. |
| Cox et al., 2020 [67] | RCCT | 52/36.5 M 23 F 29 |
REM IBD LFD/ED 27/25 |
1 | GBR | LFD and ED | IBS-SSS, GSRS, IBDQ-UK, SF, BS, HBI, PMS, 7-FC, CRP, FC, FM, FSCFA | There were 6 adverse events during the trial. There were no statistically significant differences between groups in total IBS-SSS score, HBI, PMS, FC, and CRP. The severity of flatulence, bloating, and SF was significantly lower during LFD compared with ED. Total IBDQ-UK was significantly greater following LFD (81.9, SEM 1.2) than ED (78.3, SEM 1.2). There was good adherence for both diets. |
UNRCT: Uncontrolled and non-randomized clinical trial. NRCCT: Non-randomized controlled clinical trials. RCCT: Randomized controlled clinical trials. P/m: Period (months). NI: Not indicated. IBD: Inflammatory Bowel Disease. ACT: Active disease. REM: Disease in remission. SFID: Specific food intolerance diet. UCFR: Unrefined carbohydrate fiber rich diet. CDAI: Crohn’s Disease Activity Index. ESR: Erythrocyte sedimentation rate. F: Female. M: Male. MIAID: Mediterranean-inspired anti-inflammatory diet. CRP: C-reactive protein. CSS: Cross-sectional study. MED: Mediterranean diet. IBDQ: Inflammatory Bowel Disease Questionnaire. BMI: Body mass index. BW: Bodyweight. CC: ISO Country Codes. CD: Crohn’s Disease. EG/CG: Experimental and Control Group. FE: Serum iron. HDL: High-density lipoprotein. LDL: Low-density lipoprotein. TG: Triglycerides. GGT: γ-glutamyl transferase. LDH: Lactate dehydrogenase. SGOT: Glutamic-oxaloacetic transaminase. SGPT: Glutamic-pyruvic transaminase. ALP: Alkaline phosphatase. IL-6: Serum interleukin-6. IL-10: Serum interleukin-10. HBI: Harvey–Bradshaw Index. LFD: Low FODMAP diet. SIBDQ: Short IBD questionnaire. IBS-QOL: IBS quality of life questionnaire. IBS-SSS: IBS severity score system. BS: Bristol Stool. CIBSC: Copenhagen IBS disease courses. FARS: FODMAP adherence report scale. VAS: visual analogue scales. FODMAP: Fermentable oligo-, di-, and monosaccharides and polyols. ND: Normal diet. SCCAI: Simple clinical colitis index. FC: Fecal calprotectin. FFQ: Food frequency questionnaire. VHI: Van Hees index. IP: Intestinal permeability. LCLM: Low calcium low microparticles diet. LCNM: Low calcium normal microparticles diet. NCLM: Normal calcium low microparticles diet. NCNM: Normal calcium normal microparticles diet. HEMA: Hematocrit. CA: Plasma calcium. ALB: Albumin. DMF-UC: Dietary modification framework for UC. IBDQ-UK: United Kingdom version of Inflammatory Bowel Disease. PMS: Partial Mayo score. RB: Rectal bleeding. SF: Stool frequency. PGA: Physician global assessment. MS: Mayo score. MF: Mucosa friability. EIMs: Extraintestinal manifestations. TRF: Transferrin. PA: Prealbumin. GISD: Gastrointestinal symptom diary. KED: Komperod Elimination diet. GFD: Gluten-free diet. GFDQ: Gluten-free diet questionnaire. CCS: Case-control study. TAD: Typical Australian diet. FM: Fecal microbiota. FWC: Fecal water content. FSCFA: Fecal short-chain fatty acids. PDAI: Pouchitis disease activity index. SUR: Surgery. CS: Cohort study. FL: Fecal lactoferrin. DH: Dietary history. IEC: Initial episode cases. RC: Relapse Cases. PBD: Plant-based diet. PBDS: Plant-based diet score. ED: Exclusion diet. GSRS: Gastrointestinal symptom rating scale. 7-FR: 7-day food record. SRFGS: Satisfactory relief of functional-like gastrointestinal symptoms. RCS: Retrospective cohort study. RCD: Refined carbohydrate diet. SVD: Semi-vegetarian diet. VD: Vegetarian diet. DQ: Dietary questionnaire. MTWAI: Modified Truelove and Witts activity index. SF-36: Short Form-36 health survey. SCD: Specific Carbohydrate diet. IBS: Irritable bowel syndrome. CLD: Celiac disease. WBC: White blood cells. PL: Platelets. IGED: Inmunoglobulin Exclusion Diet. LMD: Low microparticles diet. NMD: Normal microparticles diet. AIPD: Autoimmune protocol diet. MCDAI: Modified CDAI. MED: Mediterranean Diet.