Table 1

Characteristics of key nutritional trials in IBD

Inclusion of disease entityNumber of patientsDietary interventionGroupsDurationResults of the main end-point(s)References
Exclusive enteral nutrition (EEN)
Paediatric CD cases (age 3–17 years) with weighted Paediatric CD Activity Index score (wPCDAI) >40100 paediatric CDGroup1 (FL-IFX): Five infusions of 5 mg/kg IFX.
Group2 (Conventional): EEN or Oral prednisolone (1 mg/kg, maximum 40 mg)
Group1: 50 Group2: 5052 weeksFL-IFX was superior to conventional treatment in achieving short-term clinical and endoscopic remission, and had greater likelihood of maintaining clinical remissionJongsma et al113
Children with new diagnosis CD26 paediatric CDEEN6 weeksEEN is effective for inducing early clinical, biochemical, mucosal and transmural remission. Early endoscopic remission improves outcomes at 1 year.Grover et al114
New-onset active CD (aged 6–17 years) with Harvey-Bradshaw Index (HBI) >519 paediatric CDGroup1: CS
Group2: EEN
Group1: 6 Group2: 138 weeksBoth steroid and EEN induced clinical remission. Patients with EEN-induced remission showed a higher rate of mucosal healing and this was associated with a different gut microbiota compositional shift in these children.Pigneur et al115
Paediatric CD cases with a paediatric Crohn’s Disease Activity Index (PCDAI) >2050 paediatric CDGroup1: 50% PEN with unrestricted diet. Group2: 100% TENGroup1: 26 Group2: 246 weeksTEN suppresses inflammation in active Crohn’s disease but PEN does not.Johnson et al127
The Crohn’s disease and ulcerative colitis exclusion diet (CDED/UCED)
Paediatric CD cases with active disease (Paediatric Crohn’s Disease Activity Index >7.5 or Harvey-Bradshaw Index ≥4)37 paediatric CDCDED6 weeksDietary therapy involving PEN with an exclusion diet lead to high remission rates in early mild-to-moderate luminal Crohn’s disease in children and young adults.Sigall-Boneh et al128
Children with mild to moderate CD72 paediatric CDGroup1: CDED plus 50% of calories from formula for 6 weeks followed by CDED with 25% PEN for another 6 weeks.
Group2: EEN for 6 weeks followed by a free diet with 25% PEN for another 6 weeks
Group1: 40 Group2: 3812 weeksCDED plus PEN was better tolerated than EEN in children with mild to moderate CD. The combination CDED plus PEN induced sustained remission in a significantly higher proportion of patients than EEN, and produced changes in the faecal microbiome associated with remission.Levine et al41
Adult patients with CD (aged 18–55 years) with mild-to moderate CD (defined by a Harvey-Bradshaw Index score of 5–14 points)44 adult CDGroup1: CDED plus PEN
Group2: CDED alone
Group1: 20 Group2: 2424 weeks68% of patients treated with CDED plus partial enteral nutrition achieved clinical remission, which was also achieved in 57% of patients with CDED alone.Yanai et al39
Adult patients with active UC (Simple Clinical Colitis Activity Index (SCCAI) of ≥5 and ≤11 and endoscopic Mayo score 2–3)51 adult UCGroup1: Free diet plus FT.
Group2: FT with dietary pre-conditionning of the donor for 14 days and a UCED.
Group3: UCED alone
Group1: 17 Group2: 19 Group3: 158 weeksUCED alone appeared to achieve higher clinical remission and mucosal healing than single donor FT with or without diet.Sarbagili Shabat et al43
Children diagnosed with CD61 paediatric CDGroup1: CDED plus PEN (80% with prior 1–2 weeks of EEN) Group2: EENGroup1: 20 Group2: 416–8 weeksTreatment with CDED+PEN (with prior 1–2 weeks of EEN) has comparable efficacy to EEN therapy alone in inducing remission in children with CD, and it leads to better weight gain.Niseteo et al131
Patients with CD with loss of response (LoR) to biologics21 CD (11 adults and 10 children)Partial enteral nutrition (PEN)+CDED (severe paediatric patients recieved prior 14 days of EEN)12 weeksDietary treatment combining PEN with the CDED may be a useful salvage regimen for patients failing biological therapy despite dose escalation.Sigall Boneh et al133
The specific carbohydrate diet (SCD)
Paediatric patients (aged 10–17 years) with mild to moderate IBD defined by Paediatric Crohn’s Disease Activity Index (PCDAI 10–45) or Paediatric Ulcerative Colitis Activity Index (PUCAI 10–65)12 paediatric IBDSCD12 weeksSCD therapy in IBD is associated with clinical and laboratory improvements as well as concomitant changes in the faecal microbiome.Suskind et al136
The Mediterranean diet (MD)
Patients with IBD in remission58 CD and 84 UCMD6 monthsA reduction of malnutrition-related parameters and liver steatosis in patients with IBD after MD, which associated with a spontaneous improvement of disease activity and inflammatory markers.Chicco et al138
Adult patients with CD with mild-to-moderate symptoms197 adult CDGroup1: SCD Group2: MDGroup1: 101 Group2: 9612 weeksThe SCD was not superior to the MD to achieve symptomatic remission, FC response, and CRP response. Given these results, the greater ease of following the MD and other health benefits associated with the MD, the MD may be preferred to the SCD for most patients with CD with mild to moderate symptoms.Lewis et al42
The low FODMAP diet (LFD)
IBD in remission or with mild-to-moderate disease and coexisting IBS-like symptoms (Rome III)28 CD and 61 UCGroup1: LFD Group2: NDGroup1: 44 Group2: 456 weeksA low-FODMAP diet reduced IBS-like symptoms and increased quality of life in patients with IBD in remission.Pedersen et al140
IBD in remission or with mild disease activity35 CD and 20 UCGroup1: LFD Group2: SDGroup1: 26 Group2: 296 weeksLFD is safe for patients with IBD, and is associated with an amelioration of faecal inflammatory markers and quality of lifeBodini et al141
The gluten-free diet (GFD)
Patients with IBD106 patients with IBDGroup1: GFD Group2: VDGroup1: 54 Group2: 52No relevant impact of a specific diet on the course of the disease, but a significant association with lower psychological well-being in patients with VD and GFD .Schreiner et al144
  • This table summarises key aspects of recent nutritional trials in IBD.

  • CD, Crohn’s disease; CS, corticosteroid; FC, fecal calprotectin; FL, first-line treatment; FT, faecal transplantation; IBD, inflammatory bowel disease; IBS, irritable bowel syndrome; IFX, infliximab; ND, normal diet; PEN, partial enteral nutrition; SD, standard diet; TEN, total enteral nutrition; UC, ulcerative colitis; VD, vegetarian.