1.
Predictors of Symptom-Specific Treatment Response to Dietary Interventions in Irritable Bowel Syndrome.
Colomier, E, Van Oudenhove, L, Tack, J, Böhn, L, Bennet, S, Nybacka, S, Störsrud, S, Öhman, L, Törnblom, H, Simrén, M
Nutrients. 2022;14(2)
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Plain language summary
Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction, formerly known as a functional gastrointestinal (GI) disorder. Apart from abdominal pain, altered stool frequency, diarrhoea, and constipation, a large proportion of patients with IBS also experience other GI symptoms such as abdominal distention, bloating and flatulence. The aim of this study was to investigate predictors of treatment response to the low FODMAP (short-chain carbohydrates, i.e., fermentable oligo-, di-, monosaccharides, and polyols) and the traditional IBS diet while focusing on the four core IBS symptoms (bloating, constipation, diarrhoea, and pain). This study was a post-hoc analysis of a previously published randomised controlled trial. In total, 33 patients on low FODMAP diet and 34 patients on the traditional IBS diet were included in the analysis. Results showed that patterns of psychological, dietary, and microbial factors can predict IBS symptom response to two dietary advice systems—the traditional IBS and the low FODMAP diet. A clinical profile with less severe IBS features appears to predict a better symptom-specific response to both dietary interventions. Authors conclude that larger prospective randomised controlled trials which include different treatment approaches are required as they may help to optimize personalized treatment algorithms in IBS.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Dietary intervention for IBS related symptoms was efficacious for up to 75% of patients in this study
- Recommendation for a traditional IBS dietary intervention should supersede the low-FODMAP diet, with the latter only implemented when symptoms persist.
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
This randomised controlled intervention study of 67 individuals fulfilling the Rome III criteria for IBS drew comparisons between the efficacy of the traditional IBS diet - as directed by the British Dietetic Association and National Institute for Health and Care Excellence (NICE) - and the low fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) diet on specific IBS-related symptoms (pain, constipation, diarrhoea, and bloating).
Methods
A 10-day screening period included faecal sample analysis, 4-day food diary (pre-randomisation and last week of intervention), and daily stool diary (Bristol Stool Form scale). After 10 days, patients compiled several GI and non-GI related questionnaires, inclusive of IBS severity scoring system (IBS-SSS). Patients who scored ≥175 for the IBS-SSS were randomly allocated to follow either a low-FODMAP or traditional IBS diet for a period of 4-weeks. Thorough explanations were provided by trained Dietitians. During intervention, patients compiled symptom questionnaires (Gastrointestinal Symptoms Rating Scale-IBS) on a weekly basis.
Results
- Both diets reduced symptoms of pain, diarrhoea and bloating (all p<0.0001), but not constipation (p=0.15)
- There was no difference between following the traditional IBS diet and low-FODMAP diet in terms of pain (p=0.80), constipation (p=0.63), diarrhoea (p=0.96) and bloating (p=0.35)
- Less severe gut dysbiosis was weakly associated with better dietary response and improvement of constipation (p=0.05)
- Higher energy intake at baseline predicted better pain improvement with both dietary types compared to lower energy intake (p=0.03)
- More severe psychological distress predicted worse intervention response for bloating (p=0.03)
- Higher baseline oligosaccharide intake predicted a worse response to the low FODMAP diet (p=0.01) but not the traditional IBS diet (p=0.16).
Conclusion
This study demonstrated that based on 4 distinct IBS-related symptomatology, better treatment response to 2 different dietary strategies was noted in patients with less severe clinical characteristics. Higher energy intake at baseline and gut dysbiosis scores that were similar to healthy controls were associated with better improvements following dietary interventions. Thus patients who already follow a calorie restricted diet and who have more significant gut dysbiosis profiles might need more bespoke intervention. Severe psychological distress patients responded worse to both diets.
Clinical practice applications:
- Even a short 4-week specific dietary intervention (low FODMAP or traditional IBS diet) can result in IBS-related symptomatic improvement for pain, bloating, and diarrhoea, but not constipation
- The preferred starting point for dietary intervention should be the traditional IBS diet given its relative ease to follow
- The more restrictive low FODMAP protocol could be considered if symptoms persist
- More bespoke interventions are required for patients who suffer with severe psychological stress, have tested and found gut dysbiosis, and individuals who already follow a restrictive diet.
Considerations for future research:
- Future studies need to include not only larger but more diverse cultural and socio-economic cohorts to ascertain the efficacy of IBS symptom-related dietary interventions
- Longer periods of intervention are needed to confirm dietary intervention efficacy.
Abstract
(1) Background: Predictors of dietary treatment response in irritable bowel syndrome (IBS) remain understudied. We aimed to investigate predictors of symptom improvement during the low FODMAP and the traditional IBS diet for four weeks. (2) Methods: Baseline measures included faecal Dysbiosis Index, food diaries with daily energy and FODMAP intake, non-gastrointestinal (GI) somatic symptoms, GI-specific anxiety, and psychological distress. Outcomes were bloating, constipation, diarrhea, and pain symptom scores treated as continuous variables in linear mixed models. (3) Results: We included 33 and 34 patients on the low FODMAP and traditional IBS diet, respectively. Less severe dysbiosis and higher energy intake predicted better pain response to both diets. Less severe dysbiosis also predicted better constipation response to both diets. More severe psychological distress predicted worse bloating response to both diets. For the different outcomes, several differential predictors were identified, indicating that baseline factors could predict better improvement in one treatment arm, but worse improvement in the other treatment arm. (4) Conclusions: Psychological, nutritional, and microbial factors predict symptom improvement when following the low FODMAP and traditional IBS diet. Findings may help individualize dietary treatment in IBS.
2.
Efficacy and Acceptability of Dietary Therapies in Non-Constipated Irritable Bowel Syndrome: A Randomized Trial of Traditional Dietary Advice, the Low FODMAP Diet, and the Gluten-Free Diet.
Rej, A, Sanders, DS, Shaw, CC, Buckle, R, Trott, N, Agrawal, A, Aziz, I
Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2022;20(12):2876-2887.e15
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Free full text
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Plain language summary
Irritable bowel syndrome (IBS) is a common disorder characterised by stomach pain, bloating, and altered bowel movements. Dietary therapy is a way to manage IBS, with 3 diets becoming popular amongst health care professionals and those who suffer from IBS. Traditional dietary advice (TD), which involves adopting healthy, sensible eating patterns with adequate hydration, is the first line recommendation in the UK. The low-FODMAP diet (LFD) is the avoidance of carbohydrates, which tend to ferment in the stomach and are found in certain fruits and vegetables. The gluten free diet (GFD) is the avoidance of foods which contain gluten such as bread and pasta. All three diets have little evidence to support their use in IBS and this randomised control trial of 101 individuals with IBS aimed to determine whether the GFD and LFD are superior in relieving IBS symptoms compared to TD. The results showed that GFD, LFD and TD were all effective in the management of non-constipated IBS, but that TD was easier to follow and cheaper compared to the other two diets. It was concluded that TD should be used as first-line therapy for people with non-constipated IBS and that GFD and LFD should be reserved for specific patients under the care of a health care professional.
Expert Review
Conflicts of interest:
None
Take Home Message:
- TDA, LFD and GFD can all lead to significant improvements in non-constipation IBS with no statistically significant difference in effectiveness between the diets.
- Most patients find a TDA easier and cheaper to implement than a LFD or GFD.
- TDA is therefore recommended as a first line approach in non-constipation IBS.
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 study was to compare the effectiveness and patient acceptability of traditional dietary advice (TDA) vs a low FODMAP diet (LFD) vs a gluten-free diet (GFD, cross-contamination allowed) in patients with non-constipation irritable bowel syndrome (IBS).
TDA definition: healthy, sensible eating pattern, including regular meals, not eating too little/too much, adequate hydration, and reducing the intake of: alcohol/caffeine/fizzydrinks/fatty/spicy/ processed foods; fresh fruit (maximum of 3 per day); fibre/gas-producing foods and perceived food intolerances.
Methods
This was a randomised dietary trial over 4 weeks. Dietary advice was provided by a specialist dietitian in a session lasting 45-60 minutes. 99 patients completed the study (33 in each group). Stool analysis was performed in “around half“ (study authors terminology) of participants due to disruption of trial caused by COVID-19.
Results:
- Primary endpoint (reduction of 50 points or more on IBS symptom severity score) was met by 42% of patients on the TDA, 55% on LFD and 58% on GFD. The differences between groups were not statistically significant, p=0.43.
- Patients on the LFD had greater improvements in mood compared to the other diets under examination, reaching statistical significance (p=0.03) for Hospital Anxiety and Depression scale and (p<0.01) for dysphoria score on IBS-QOL scale.
- Patients on TDA found their diet cheaper (p<0.01), less time consuming to shop (p<0.01) and easier to follow when eating out with family and friends (p=0.03), whilst TDA and GFD were considered easier to incorporate into daily diet than LFD (p=0.02).
- No significant differences were found between groups in changes to macro- and micronutrient composition, except a trend to lower fibre intake with LFD (p=0.06).
- There was a significant reduction in intake of FODMAPs in all groups, with greatest reduction in LFD (27.7 to 7.6 g/day, p<0.01), followed by TDA (24.9 to 15.2 g/day, p<0.01) and GFD (27.4 to 22.4 g/day, p=0.03). Differences between groups were statistically significant (p<0.01).
- No differences were noted in change to the dysbiosis index between groups.
- Neither clinical characteristics nor dysbiosis index predicted response to any of the diets.
Conclusion
- TDA, LFD and GFD are all effective approaches for non-constipation IBS.
- TDA should be first-line dietary advice due to being the most patient-friendly.
Clinical practice applications:
- When working with clients with non-constipation IBS, a TDA approach may be favoured over LFD and GFD as a first line intervention if the patient has not already tried a TDA diet.
- Patient preferences, budget, time and living situation should be taken into account when deciding on best dietary advice for IBS.
Considerations for future research:
- As all 3 approaches led to reduction in FODMAPs, trials comparing different levels of FODMAP exclusion could lead to valuable information, as a strict FODMAP exclusion, which is commonly recommended in IBS, is difficult and may not be necessary.
- Studies of longer duration would be valuable to confirm that benefits observed with the 3 approaches are not short-term only.
- Comparing individual approaches to appropriate control group would ensure that improvements are not due to a placebo effect.
Abstract
BACKGROUND & AIMS Various diets are proposed as first-line therapies for non-constipated irritable bowel syndrome (IBS) despite insufficient or low-quality evidence. We performed a randomized trial comparing traditional dietary advice (TDA) against the low FODMAP diet (LFD) and gluten-free diet (GFD). METHODS Patients with Rome IV-defined non-constipated IBS were randomized to TDA, LFD, or GFD (the latter allowing for minute gluten cross-contamination). The primary end point was clinical response after 4 weeks of dietary intervention, as defined by ≥50-point reduction in IBS symptom severity score (IBS-SSS). Secondary end points included (1) changes in individual IBS-SSS items within clinical responders, (2) acceptability and food-related quality of life with dietary therapy, (3) changes in nutritional intake, (4) alterations in stool dysbiosis index, and (5) baseline factors associated with clinical response. RESULTS The primary end point of ≥50-point reduction in IBS-SSS was met by 42% (n = 14/33) undertaking TDA, 55% (n = 18/33) for LFD, and 58% (n = 19/33) for GFD (P = .43). Responders had similar improvements in IBS-SSS items regardless of their allocated diet. Individuals found TDA cheaper (P < .01), less time-consuming to shop (P < .01), and easier to follow when eating out (P = .03) than the GFD and LFD. TDA was also easier to incorporate into daily life than the LFD (P = .02). Overall reductions in micronutrient and macronutrient intake did not significantly differ across the diets. However, the LFD group had the greatest reduction in total FODMAP content (27.7 g/day before intervention to 7.6 g/day at week 4) compared with the GFD (27.4 g/day to 22.4 g/day) and TDA (24.9 g/day to 15.2 g/day) (P < .01). Alterations in stool dysbiosis index were similar across the diets, with 22%-29% showing reduced dysbiosis, 35%-39% no change, and 35%-40% increased dysbiosis (P = .99). Baseline clinical characteristics and stool dysbiosis index did not predict response to dietary therapy. CONCLUSIONS TDA, LFD, and GFD are effective approaches in non-constipated IBS, but TDA is the most patient-friendly in terms of cost and convenience. We recommend TDA as the first-choice dietary therapy in non-constipated IBS, with LFD and GFD reserved according to specific patient preferences and specialist dietetic input. CLINICALTRIALS gov: NCT04072991.