Systematic review: quality of trials on the symptomatic effects of the low FODMAP diet for irritable bowel syndrome.
Study Goal
The researchers aimed to systematically review the quality of randomized controlled trials (RCTs) assessing the symptomatic effects of the low-FODMAP diet for irritable bowel syndrome (IBS).
Results Summary
The review found that RCTs on the low-FODMAP diet had a high risk of bias, particularly in blinding, and lacked long-term studies beyond 6 weeks. There was concern that reported symptomatic effects might be driven by placebo responses.
Population
Patients with irritable bowel syndrome (IBS) (542 participants across 9 RCTs).
Effective Dosage
Not specified (interventions included provided meals or dietary instruction).
Duration
2 days to 6 weeks (one trial included a 6-month follow-up).
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low FODMAP diet | neutral | IBS symptoms | patients with irritable bowel syndrome (IBS) | - | symptomatic effects | #1 |
low FODMAP diet | neutral | RCTs | - | - | characterized by high risk of bias | #2 |
low FODMAP diet | no change | randomised, controlled setting for more than 6 weeks | - | - | has not been studied | #3 |
low FODMAP diet | no change | important reintroduction period | - | - | trials examining the effect are lacking | #4 |
low FODMAP diet | neutral | symptomatic effects | - | - | risk that the symptomatic effects are driven primarily by a placebo response | #5 |
BACKGROUND: The low Fermentable Oligo-, Di- Monosaccharides, and Polyoles (FODMAP) diet is a new treatment option for irritable bowel syndrome (IBS). Experts refer to the diet as supported by high level of evidence, but an evaluation of the quality of trials is lacking. AIM: To provide a systematic review of the quality of trials on the symptomatic effects of the low FODMAP diet for IBS. METHODS: Pubmed and EMBASE were searched for randomised controlled trials (RCTs) reporting effect of the low FODMAP diet on IBS symptoms. The quality of trials was evaluated by estimating risk of bias and assessing trial methodology. RESULTS: Nine RCTs were eligible, including 542 patients. The intervention period was from 2 days to 6 weeks and one trial included a 6-month follow-up. Three trials intervened by providing meals, controlling with a diet high in FODMAP content. In six trials, the intervention was instruction by a dietician and a variety of control interventions were used, all with limited established efficacy. Domains with a high risk of bias were identified for all the trials. High risk of bias dominated domains regarding blinding, with only one trial double-blinded. CONCLUSIONS: The RCTs on the low FODMAP diet are characterized by high risk of bias. The diet has not been studied in a randomised, controlled setting for more than 6 weeks and trials examining the effect of the important reintroduction period are lacking. There is a risk that the symptomatic effects reported in the trials are driven primarily by a placebo response.