Plain language summary
Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction, characterised by chronic abdominal pain and altered bowel habits. Currently, many patients follow an exclusion diet where specific food components are eliminated. One of these exclusion diets is a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). The primary aim of this study was to compare the effects of diets with low vs. moderate FODMAP content on gastrointestinal (GI) symptoms in IBS. This study was a double-blind, randomised, controlled, crossover study which enrolled 31 participants who were randomly assigned to the diet periods. Results showed that the severity of GI symptoms was reduced, and bowel habits were affected in the direction of less frequent and firmer stool by the low FODMAP diet, but not by a diet with moderate amounts of FODMAPs. Authors conclude that assessment of overall IBS severity and predominant bowel habits before the intervention may be helpful for clinicians in their IBS management before considering a trial period with the low FODMAP diet as a treatment option.
Expert Review
Conflicts of interest:
None
Take Home Message:
A low (4 g/day) FODMAP diet could provide clinical benefits in the context of an acute strategy for IBS clients with frequent loose stools (IBS-Diarrhoea and/or IBS-Mixed) compared to those with hard and less frequent stools (IBS-Constipation) to improve the severity of GI symptoms, including lower abdominal pain intensity and frequency, bowel habits, daily life interference, and psychological distress.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
The aim of this paper was to investigate the effects of diets with low vs. moderate FODMAP content on gastrointestinal (GI) symptoms and bowel habits, and to identify possible predictors of clinical response to a low FODMAP diet and FODMAP sensitivity in Irritable Bowel Syndrome (IBS).
Methods
- This study involved a double-blind, randomised, controlled, crossover trial of 29 participants (18-75 years), mostly female, diagnosed with IBS (Rome IV)
- The primary outcome was to assess the effects of a low (4 g/day) vs. moderate (23 g/day) FODMAP diet on GI symptoms over a 7-day period
- Secondary outcomes involved assessing the effects of low vs. moderate FODMAP diets on i) somatic symptoms, ii) psychological distress, iii) predictors of clinical and IBS-Severity Scoring System (IBS-SSS) sensitivity to FODMAP
- Breakfast was standardised, with prescribed low FODMAP list deviations recorded
- Main dishes and snacks were also provided
- Participants were requested to limit alcohol, caffeine, fatty- and spicy foods, ate regularly, chewed thoroughly and drank enough water
- GI symptoms and bowel habits were recorded during the 7-day screening period, then participants undertook a Lactulose Nutrient Challenge Test (LNCT)
- The first 7-day diet started one day after the LNCT
- A 14-day wash-out period allowed participants to eat and drink as usual, thereafter following the second 7-day diet period as part of the cross over design.
Results
A low FODMAP intervention (compared to a moderate FODMAP diet); resulted in:
- Reduced overall IBS rating (10 ± 72 vs. 57 ± 108, P=0.04)
- Improved abdominal pain frequency (10 ± 32 vs. 18 ± 29 (P=0.02)
- Improved stool consistency (0.2 ± 1.0 vs. 0.6 ± 1.2, P= 0.01) and frequency (0.1 ± 0.7 vs. 0.4 ± 0.7, P= 0.01)
- Overall, 34% of participants positively responded to the low FODMAP diet, which could be predicted based on higher baseline IBS-SSS scores (P=0.02)
- Participants sensitive to FODMAPs had increased pre- and postprandial ratings of gas, abdominal pain and bloating and higher exhaled methane concentrations compared to non-sensitive participants to FODMAPs
- Authors highlighted a non-significant association between FODMAP sensitivity and GI symptoms during the LNCT, with higher visceral hypersensitivity (45 ± 20, P=0.73) after ingestion of poorly absorbed and fermentable carbohydrates, with no independent predictors identified.
Conclusions
This study showed that a diet low in FODMAPs reduces GI symptoms and positively impacts bowel habits in IBS, compared with a moderate FODMAP diet.
Clinical practice applications:
- While this was a short term study, a low FODMAP diet reduced GI symptoms and affected bowel habits (more firm and less frequent stools) in IBS, compared with a diet containing moderate amounts of FODMAPs
- Knowing the above, an assessment of overall IBS severity and predominant bowel habits before the intervention may be helpful for clinicians working with younger females in their IBS management before considering a trial period with the low FOD-MAP diet as a treatment option.
Considerations for future research:
- Future trials could target a larger sample size with a more representative population, as well as assessing low FODMAP interventions over longer timeframes
- . Additionally, the assessment of biological measures such as microbiota diversity and stability, as well as metabolites (such as short chain fatty acids) could be important to understand mechanistic attributes of low FODMAP diets in IBS.
Abstract
BACKGROUND & AIMS Fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) can provoke symptoms in patients with irritable bowel syndrome (IBS). We aimed to compare the effects of diets with low vs. moderate FODMAP content on gastrointestinal (GI) symptoms and bowel habits, and to identify possible predictors of clinical response to a low FODMAP diet and FODMAP sensitivity in IBS. METHODS Adult participants with IBS (Rome IV criteria, n = 29) were included and adhered to two 7-day diet periods, with either low (4 g/day) or moderate (23 g/day) amounts of FODMAPs, in this randomized, double-blind, crossover study. The periods were separated by a wash-out period (≥14 days). IBS-Severity Scoring System (IBS-SSS) and a stool diary (Bristol Stool Form) were completed before and after the diet periods. At baseline, severity of GI symptoms and gut microbial fermentation were assessed (every 15 min, 4 h) during the Lactulose Nutrient Challenge Test (LNCT). Clinical response and FODMAP sensitivity were defined by reduction after low FODMAP period, and increase after moderate FODMAP period in IBS-SSS (≥50 points), respectively. RESULTS Severity of GI symptoms (P = 0.04), stool consistency (P = 0.01), and stool frequency (P = 0.01) differed between the interventions, with reduced overall GI symptom severity, abdominal pain intensity and frequency, bowel habits dissatisfaction, and daily life interference (P < 0.05 for all), as well as more firm (P = 0.03) and less frequent (P < 0.01) stools after low FODMAP intervention, but not after moderate FODMAP intervention. A third (34%) responded clinically to the low FODMAP diet, and the response could be predicted by higher IBS-SSS at baseline (P = 0.02). Although modest associations between FODMAP sensitivity (22%) and GI symptoms during LNCT were observed, no independent predictors could be identified. CONCLUSIONS A diet low in FODMAPs reduces GI symptoms and affects bowel habits in IBS, compared with a moderate FODMAP diet. Assessment of IBS severity before the intervention may be used to predict clinical response to a low FODMAP diet. Trial registry (http://www. CLINICALTRIALS gov): Registered under Clinical Trial number NCT05182593.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
