Low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diet in patients with diarrhea-predominant irritable bowel syndrome: A prospective, randomized trial

Gut feeling gone wrong: Tangled relationship between disorders of gut-brain interaction and liver disease

Functional gastrointestinal disorders, now termed “disorders of gut-brain interaction” (DGBI), are characterized by a spectrum of chronic gastrointestinal symptoms driven by dysregulated gut-brain interaction. DGBIs frequently coexist with liver diseases, including cirrhosis, thereby exacerbating clinical manifestations and complicating management; this overlap is underpinned by shared mechanisms, including gut dysbiosis, increased intestinal permeability, systemic inflammation, and altered neuroimmune signaling. Portal hypertension in cirrhosis promotes small intestinal bacterial overgrowth and microbial translocation, thereby triggering inflammatory pathways that worsen gut and liver function. This minireview explores the gut-liver axis as a central mediator in the interplay between DGBIs and liver disease/cirrhosis. Clinically, these interactions manifest as refractory gastrointestinal symptoms, nutritional deficiencies, and impaired quality of life. Emerging research emphasizes the need for integrative diagnostic approaches, such as combining advanced imaging, microbiome analysis, and biomarker profiling, to unravel the complex interplay between DGBIs and liver disease/cirrhosis. Therapeutic interventions targeting the gut microbiome, neuroimmune pathways, and lifestyle modification can mitigate disease burden. This review underscores the importance of a multidisciplinary framework for enhancing patient outcomes and guiding future research in this intersectional field.

2025 Seoul Consensus on Clinical Practice Guidelines for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a chronic, disabling, and functional bowel disorder that significantly affects social functioning and reduces quality of life and increases social costs. The Korean Society of Neurogastroenterology and Motility published clinical practice guidelines on the management of IBS based on a systematic review of the literature in 2017, and planned to revise these guidelines in light of new evidence on the pathophysiology, diagnosis, and management of IBS. The current revised version of the guidelines is consistent with the previous version and targets adults diagnosed with or suspected of having IBS. These guidelines were developed using a combination of de novo and adaptation methods, with analyses of existing guidelines and discussions within the committee, leading to the identification of key clinical questions. Finally, the guidelines consisted of 22 recommendations, including 3 concerning the definition and risk factors of IBS, 4 regarding diagnostic modalities and strategies, 2 regarding general management, and 13 regarding medical treatment. For each statement, the advantages, disadvantages, and precautions were thoroughly detailed. The modified Delphi method was used to achieve expert consensus to adopt the core recommendations of the guidelines. These guidelines serve as a reference for clinicians (including primary care physicians, general healthcare providers, medical students, residents, and other healthcare professionals) and patients, helping them to make informed decisions regarding IBS management.

Clinical Trial: A Mediterranean Low-FODMAP Diet Alleviates Symptoms of Non-Constipation IBS-Randomized Controlled Study and Volatomics Analysis

Background: Approximately 20% of patients with irritable bowel syndrome (IBS) link symptoms to food intake; a low-FODMAP diet is effective in managing these symptoms. Aims: To evaluate the effectiveness of the Mediterranean version of the low-FODMAP Diet (MED-LFD) compared to NICE guidelines for IBS and to assess changes in stool volatile compound levels. Methods: 108 patients with Rome IV IBS without constipation were randomized into the MED-LFD or NICE group. Primary endpoints included changes in symptom severity and responder rate (reduction of >50 IBS-SSS points) after intervention and at 6 months. Secondary endpoints assessed quality of life, symptom burden, adequate relief, anxiety/depression levels, and adherence. Volatile compound levels were measured using Gas Chromatography/Mass Spectrometry. Results: At both time points, the MED-LFD group showed a significantly greater improvement in symptom severity (159 ± 80 vs. 253 ± 94 and 168 ± 117 vs. 245 ± 98), responder rates (84.6% vs. 60.8% and 79.1% vs. 52.3%), and adherence (75% vs. 41% and 45% vs. 7%). Similar results were observed for all secondary endpoints, with no serious adverse events reported. The MED-LFD intervention was the strongest independent predictor of being a responder at the first (OR = 6.66; 95%CI = 1.46, 30.4) and second follow-up (OR = 4.85; 95%CI = 1.31, 17.96). Short and branched-chain fatty acids were significantly reduced at both follow-ups. Conclusions: The MED-LFD is superior to NICE recommendations in managing non-constipated IBS symptoms and quality of life. It remains to be proven that reduced volatile compound levels might be an objective marker of response to dietary interventions. ClinicalTrials.gov ID: NCT03997708.

Overlap of 'disorders of gut-brain interaction' and their impact on quality of life and somatization in a tertiary care center- A cross-sectional study

BACKGROUND

Disorders of gut-brain interaction (DGBIs) constitute a global health challenge. Overlapping DGBIs amplify the clinical severity and have a profound impact on health-related quality of life (HRQoL) and somatization. Data on the prevalence and overlap of all individual DGBIs and their clinical ramifications remains limited. This study sought to elucidate these aspects within a northern Indian tertiary healthcare setting.

METHODS

This prospective cross-sectional study enrolled patients meeting Rome IV criteria for DGBIs and healthy controls (HC). Participants underwent elaborative assessments, including socio-demographic profiling, HRQoL evaluation (PROMIS Global-10) and somatization quantification (PHQ-12). Statistical analyses compared prevalence rates, overlap patterns and associated clinical outcomes between various groups.

RESULTS

Of the 2538 patients screened, 1044 (41.1%) with DGBIs (age 41.7 ± 12.6 years, 51.9% males) were enrolled; along with 1021 age and gender-matched HCs. Most common gastrointestinal region involved was gastroduodenal (49.9%), followed by bowel (39.7%) and esophageal (33.3%). Most common DGBIs were functional dyspepsia (FD; 44.4%), functional esophageal disorders (FEsD;32.4%), functional constipation (FC;18%), irritable bowel syndrome (IBS;16.1%). Overlapping DGBIs were present in 40.3% patients, with FD-FEsD (23.9%) and FD-FC(22.1%) and FD-IBS (52;12.4%) overlaps being the most common. Compared to HC, DGBI patients had significantly poorer HRQoL scores (19.1 ± 0.7 vs. 13.52 ± 3.39; p < 0.001) and significantly increased somatization scores (2.5 ± 1.7 vs. 18.5 ± 0.7; p < 0.001). Further, patients with overlapping DGBIs had significantly poorer HRQoL and significantly increased somatization scores compared to non-overlapping counterparts.

CONCLUSIONS

This study provides novel data on the clinical burden and the entire spectrum of overlapping and non-overlapping DGBIs, while studying their impact on HRQoL and somatization. DGBI patients had significantly poorer HRQoL and heightened somatization compared to HCs; with further detriments observed in those with overlapping DGBIs. These findings emphasize the need for an integrated multidisciplinary approach for the evaluation of possible overlaps and for assessment of HRQoL in all patients with DGBIs to improve clinical outcomes.

Nutritional Interventions in Adult Patients With Irritable Bowel Syndrome: An Umbrella Review of Systematic Reviews and Meta-analyses of Randomized Clinical Trials

CONTEXT

There is still debate regarding the effect of nutritional interventions in improving irritable bowel syndrome (IBS) symptoms.

OBJECTIVES

The aim was to examine the evidence certainty and validity of all existing meta-analyses of intervention trials on nutritional interventions in patients with IBS.

DATA SOURCES

Scopus, PubMed, and Web of Science were reviewed until June 2023.

DATA EXTRACTION

Meta-analyses assessing the impacts of nutritional interventions in adults with IBS were entered. Effect sizes of nutritional interventions were recalculated by applying a random-effects model. GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) was implemented to determine evidence certainty.

RESULTS

A total of 175 trials in 58 meta-analyses were entered describing the effects of 11 nutritional interventions on IBS-related outcomes. Nutritional interventions had beneficial effects on some IBS-related outcomes. For instance, soluble fiber, peppermint oil, and aloe vera improved IBS symptoms, and vitamin D3 and curcumin improved IBS symptom severity. Tongxieyaofang improved abdominal pain severity and stool frequency. Nevertheless, these outcomes have mainly shown small effects and low to very low evidence certainty. With regard to abdominal pain after probiotic supplementation (relative risk [RR]: 4.04; 95% confidence interval [CI]: 2.36, 6.92; GRADE = moderate) and IBS symptoms after a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (RR: 1.48; 95% CI: 1.14, 1.93; GRADE = moderate), there was evidence that probiotics and a low-FODMAP diet can confer clinical and favorable effects.

CONCLUSION

The current review does not support nutritional interventions for improving IBS symptoms. With regard to probiotics and a low-FODMAP diet, considering limitations like short-term study duration, there was an influential clinical impact.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023429991.

The low FODMAP diet in adolescents functional abdominal in a non-guided setting: a prospective multicenter cohort study

The purpose of this study is to evaluate the efficacy of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) in adolescents with irritable bowel syndrome (IBS) and functional abdominal pain-not otherwise specified (FAP-NOS) in a non-guided setting, resembling clinical practice. This prospective multicenter cohort study conducted in 13 centers included patients aged 12-18 years diagnosed with IBS or FAP-NOS. Patients received educational material on FODMAPs, including extensive lists of high and low FODMAP foods and additional online information. They were instructed to replace high FODMAP foods with low FODMAP alternatives for the duration of 4 weeks. No dietician was consulted. The primary end point was the proportion of patients with treatment success (≥ 30% reduction of abdominal pain intensity) at 4 weeks. The key secondary outcome was adequate relief of IBS/FAP-NOS symptoms. Of the 325 included patients, 81 patients (24.9%) achieved treatment success (≥ 30% reduction of abdominal pain intensity) after 4 weeks, with higher rates in patients with IBS (29.3%) than FAP-NOS (16.8%, OR 2.16 (1.04-4.48)). Adequate relief was reported in 51 patients (15.7%). There was a significant decrease in abdominal pain intensity (2.2 (1.1) vs. 2.5 (1.0), P < 0.001), daily bloating (2.4 (2.1) vs. 2.8 (2.3), P < 0.001), and flatulence (2.4 (2.1) vs. 2.8 (2.3), P = 0.001). Adverse events were mild and infrequent.

CONCLUSION

The low FODMAP diet in a non-guided setting, mimicking clinical practice, yielded treatment success in almost 30% adolescents with IBS and 17% in FAP-NOS, suggesting it may not be the first treatment option for these patients.

TRIAL REGISTRATION

EUCTR2015-003293-32-NL.

WHAT IS KNOWN

• Irritable bowel syndrome (IBS) and functional abdominal pain-not otherwise specified (FAP-NOS) are common disorders in children which negatively impact quality of life. • While a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) has demonstrated effectiveness in adult IBS, its efficacy in pediatric IBS and FAP-NOS remains uncertain. • Clinical application of the low FODMAP diet often occurs without dietician consultation, contrary to controlled trial settings.

WHAT IS NEW

• The low FODMAP diet, without dietician guidance, resulted in treatment success in almost 30% of adolescents with IBS and only 17% with FAP-NOS. • With only 15.7% of participants achieving adequate relief of IBS/FAP-NOS symptoms, the non-guided low FODMAP diet may not be the first treatment option for pediatric IBS and FAP-NOS.

A service evaluation of FODMAP restriction, FODMAP reintroduction and long-term follow-up in the dietary management of irritable bowel syndrome

BACKGROUND

The dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), called the low-FODMAP diet (LFD), is frequently used to manage irritable bowel syndrome (IBS). This service evaluation aimed to assess the long-term effectiveness of the LFD in managing IBS symptoms and whether symptom response and dietary adherence to the LFD were associated.

METHODS

This observational service evaluation collected data via questionnaires during clinical dietetic appointments for IBS management. Symptom severity was reported at baseline, short term (following FODMAP restriction) and long term (following FODMAP reintroduction). Additional data that captured experiences following the LFD were collected at long-term follow-up.

RESULTS

Of 184 patients, 14% reported satisfactory relief from global symptoms at baseline, which increased to 69% at short-term follow-up and 57% at long-term follow-up (p < 0.001). The most notable improvements in individual symptoms between baseline and long-term follow-up were abdominal bloating (72% baseline, 48% long term, p < 0.001), abdominal pain (61% baseline, 30% long term, p < 0.001) and flatulence (71% baseline, 40% long term, p < 0.001). High adherence with the LFD at short-term follow-up was not associated with long-term symptom improvement, but there was an association between long-term adherence and global symptom severity (p = 0.032). Completion of FODMAP reintroduction as per protocol was associated with long-term symptom improvement (p = 0.049).

CONCLUSIONS

The LFD is an effective treatment for managing IBS symptoms in the long term, particularly, when the diet is adhered to and reintroduction is completed as per dietetic education. Further randomised-controlled trials are required to explore the cause-and-effect relationship between LFD and IBS symptom management.

Effects of Probiotics and Diet Management in Patients With Irritable Bowel Syndrome: A Systematic Review and Network Meta-analysis

CONTEXT

The efficacy of probiotics and diet management in irritable bowel syndrome (IBS) is controversial, and their relative effectiveness remains unclear.

OBJECTIVE

This study aimed to evaluate the effects of probiotics, diet management, and their combination on IBS.

DATA SOURCES

PubMed, Embase, Cochrane, and Web of Science were searched from inception to July 10, 2023, for relevant studies, including symptom relief, IBS-symptom severity score (-SSS), and IBS-quality of life measure (-QOL).

DATA EXTRACTION

Two investigators independently performed the data extraction and quality assessment.

DATA ANALYSIS

A network meta-analysis was performed using a frequentist approach and a random-effects model to estimate the relative risk (RR) and 95% CI.

RESULTS

Forty-four articles were eligible for this study. In relieving IBS symptoms, compared with a sham diet, a low-fermentable oligosaccharide, disaccharide, monosaccharide, and polyols (low-FODMAP) diet (RR: 3.22; 95% CI: 1.70-6.26) and low-FODMAP diet combined with probiotics (RR: 17.79; 95% CI: 3.27-112.54) significantly relieved IBS symptoms. The control group showed significantly lower effectiveness than the probiotics group (RR: 0.47; 95% CI: 0.32-0.69). According to the surface under the cumulative rank curve (SUCRA), a low-FODMAP diet combined with probiotics (80.4%) had the best effect in relieving IBS symptoms, followed by a low-FODMAP diet (70.8%), probiotics (65.1%), and a gluten-free diet (54.3%). In reducing the total IBS-SSS, the low-FODMAP diet (90.5%) was the most effective, followed by the low-FODMAP diet combined with probiotics (76.6%), probiotics alone (62.3%), and gluten-free diet (28.3%). In reducing total IBS-QOL, probiotics (72.1%) ranked first, followed by gluten-free (57.0%) and low-FODMAP (56.9%) diets. Probiotics (34.9%) were associated with the lowest risk of adverse effects.

CONCLUSION

A low-FODMAP diet combined with probiotics is most effective in relieving IBS symptoms. A low-FODMAP diet is the most recommended diet for alleviating IBS severity, and probiotics were associated with improving the QOL of patients with IBS, with the fewest adverse events.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42024499113.

The Efficacy of the Low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) Diet in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Irritable bowel syndrome (IBS) is frequently observed in clinical practice and affects people from different parts of the world. The pathogenesis and aetiology are not well-defined or fully understood; however, altered bowel movements, psychological factors, and visceral hypersensitivity may contribute to symptoms via a pathway mediated by serotonin and other enteric neurotransmitters. Altered bowel movements, including diarrhoea and constipation, abdominal pain relieved by passing flatus, and bloating are the main salient features of this condition. This systematic review and meta-analysis aimed to determine the effectiveness and efficacy of a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (low-FODMAP) diet in these patients. Systematic searches were conducted on PubMed, Medline, Google Scholar, and Cochrane Library. Randomised controlled trials (RCTs), systematic trials and cohort studies that included keywords about IBS and a low-FODMAP diet were included. Exclusion criteria included studies that were not in the English language, not relevant to IBS, diet-related to inflammatory bowel disease, or not pertinent to the subject. A total of 41 studies were included in this systematic review and meta-analysis. There was significant heterogeneity among the RCTs; hence, a random-effects model was used. The systematic review included a total of 8460 patients across 36 studies, with follow-up durations ranging from 11 to 16 months. Specifically, the meta-analysis included 15 RCTs with 1118 participants and follow-up durations from two days to nine weeks and six cohort studies including 292 patients with follow-up durations from two weeks to two years. The risk ratio (RR) was 1.21 (95% confidence interval= 0.98-1.51), and the I2 value ​​​​​was 63% for global symptom improvement with a low-FODMAP diet using a random-effects model. There was a low risk of bias in the RCTs. Five studies were included evaluating the effect of a low-FODMAP diet on quality of life, and these studies did not show any statistically significant benefit of a low-FODMAP diet on quality of life, although a mean difference of 4.59 (95% CI 1.50-7.67) was observed. The risk of bias was moderate to severe in the observational studies included in this review. Food intolerance is increasingly recognised as a contributory factor in IBS, and its role in the pathogenesis and precipitation of symptoms is being explored. Specific mechanisms include the fermentation of FODMAPs by the gut microbiota, leading to gas production and subsequent symptoms.

Efficacy of Dietary Interventions for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

Introduction: Irritable bowel syndrome (IBS) is a common condition that alters the quality of life of patients. A variety of dietary interventions have been introduced to address this debilitating condition. The low-FODMAP diet (LFD), gluten-free diet (GFD), and Mediterranean diet are examples showing efficacy. The aim of this network meta-analysis was to compare these interventions to find the best approach. Methods: We performed a systematic review of the available literature through 14 March 2024 in the following databases: Embase, PubMed, MEDLINE OVID, Web of Science, CINAHL Plus, and Cochrane Central. We only included randomized controlled trials (RCTs). We used a random effects model and conducted a direct meta-analysis based on the DerSimonian-Laird approach and a network meta-analysis based on the frequentist approach. Mean differences (MDs) with 95% confidence interval (CI) were calculated. The primary outcomes included IBS quality of life (IBS QOL) and IBS symptom severity scale (IBS-SSS). Results: We finalized 23 studies including 1689 IBS patients. In the direct meta-analysis, there was no statistically significant difference in any IBS score between GFD and either LFD or standard diet. Meanwhile, the LFD was statistically superior to the standard diet in the IBS-SSS (MD: -46.29, CI: -63.72--28.86, p < 0.01) and IBS QOL (MD: 4.06, CI: 0.72-7.41, p = 0.02). On ranking, the Mediterranean diet showed the greatest improvement in IBS-SSS, IBS-QOL, distension, dissatisfaction, and general life interference, followed by the LFD alone or in combination with the GFD. Conclusions: We demonstrated the efficacy of dietary interventions such as the LFD and Mediterranean diet in improving IBS. There is a need for large RCTs with head-to-head comparisons, particularly for the Mediterranean diet.

Dietary management of irritable bowel syndrome: considerations, challenges, and solutions

Diet is a cornerstone in the management of irritable bowel syndrome (IBS). There is evidence of efficacy across the spectrum of dietary management strategies, including some supplements (eg, specific fibres), foods, and whole diets (eg, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols [known as the low-FODMAP diet]). Whole-diet interventions, in particular those that restrict intake, can be challenging to deliver effectively and safely. Factors to consider include patient demographics, food cost and availability, and the acceptability of dietary management and its impact on food-related quality of life. There is concern regarding a potential role of restrictive whole-diet interventions in eating disorder risk. Optimal approaches to delivering dietary management in the health-care setting are unclear. The aim of this Review is to summarise the clinical evidence for the dietary management of IBS; to discuss the challenges, burdens, and risks of dietary management; and to propose how these challenges, burdens, and risks should be mitigated and minimised in clinical practice.

Practices and Barriers in Implementing the Low FODMAP Diet for Irritable Bowel Syndrome Among Malaysian Dietitians: A Qualitative Study

The low fermentable oligo-, di-, mono-saccharides and polyols (FODMAP) diet (LFD) is a second-line dietary intervention for irritable bowel syndrome (IBS) patients, involving FODMAP restriction, reintroduction, and personalization, and it needs to be delivered by dietitians. However, the application of this diet among Malaysian IBS patients is not well understood. This study aimed to explore the practices and barriers in delivering the LFD among Malaysia dietitians. Semi-structured qualitative interviews were conducted online with practicing dietitians until the data reached saturation. All the interview sessions were audio recorded and transcribed verbatim. Thematic analysis was used to analyze the data. Eleven dietitians were interviewed, with 36.4% (n = 4) having more than 10 years of experience. The following four themes regarding their practices emerged: 1. dietary advice on FODMAP restriction; 2. duration of FODMAP restriction phase; 3. references used to get information about FODMAPs, and 4. strategies on reintroduction. Meanwhile, the following seven barriers were identified: 1. lack of culturally relevant educational materials; 2. limited knowledge about the LFD; 3. inadequate formal training among dietitians; 4. lack of integration in multi-disciplinary care; 5. low health literacy of patients; 6. low compliance rate among patients, and 7. restrictions for certain populations. LFD implementation in Malaysia is not standardized as only experienced dietitians can provide dietary evidence-based advice. Lack of training and culturally specific resources are some of the main barriers that were identified to be limiting the implementation of the diet. Therefore, there is a need for training programs and resource development to support Malaysian dietitians in managing IBS patients.

A diet low in fermentable oligo-, di-, monosaccharides and polyols improves abdominal and overall symptoms in persons with all subtypes of irritable bowel syndrome

BACKGROUND

A diet low in fermentable oligo-, di-, monosaccharides and polyols (LFD) improves symptoms in patients with irritable bowel syndrome (IBS). Previous studies have focused on patients with IBS and diarrhea (IBS-D). It is unclear whether LFD is effective for IBS with constipation (IBS-C) or IBS with mixed bowel habits (IBS-M). This open-label, real-world study evaluates the relative effectiveness of the LFD among IBS subtypes.

METHODS

This study analyzes data from a service that provides low-FODMAP meals to individuals with IBS. Participants met with a registered dietitian and completed the IBS symptom severity survey (IBS-SSS) before and after undergoing a 2-4-week period of FODMAP restriction. The primary endpoint was the proportion of participants with ≥50-point decrease in IBS-SSS between the three IBS subtypes.

KEY RESULTS

After FODMAP restriction, 90% of participants with IBS-D, 75% with IBS-C, and 84% with IBS-M met the primary endpoint (p = 0.045). Similar improvement was seen for a 100-point decrease, but the difference between IBS subtypes was not significant (p = 0.46). After FODMAP restriction, all groups had statistically significant improvement in total IBS-SSS as well as individual symptom categories. Improvement in IBS-SSS subcategories was similar among the groups except for the categories of bloating severity (IBS-M had greatest improvement) and bowel movement satisfaction (IBS-C had less improvement).

CONCLUSION & INFERENCES

Though the proportion of responders was highest for IBS-D and lowest for IBS-C, the LFD led to robust improvement in overall symptoms in all IBS subtypes. Key individual symptoms also showed significant improvements in all IBS subtypes.

DOMINO trial post hoc analysis: evaluation of the diet effects on symptoms in IBS subtypes

Background

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction characterized by recurrent abdominal pain related to defecation and/or associated to a change in bowel habits. According to the stool type, four different IBS subtypes can be recognized, constipation predominant (IBS-C), diarrhea predominant (IBS-D), mixed (IBS-M), and undefined (IBS-U). Patients report that their IBS symptoms are exacerbated by food. Thus, it is important to find a nutritional approach that could be effective in reducing IBS symptoms.

Objective

The present work is a post hoc analysis of the previously published DOMINO trial. It aimed to evaluate the effects of a self-instructed FODMAP-lowering diet smartphone application on symptoms and psychosocial aspects in primary care IBS stratifying the results for each IBS subtypes.

Design

Post hoc analysis.

Methods

Two hundred twenty-two primary care IBS patients followed a FODMAP-lowering diet for 8 weeks with the support of a smartphone application. Two follow-up visits were scheduled after 16 and 24 weeks. IBS-Symptoms Severity Score (IBS-SSS), quality of life (QoL), and adherence and dietary satisfaction were evaluated.

Results

After 8 weeks, IBS-SSS improved in all IBS subtypes (p < 0.0001). Physician Health Questiionnaire (PHQ-15) improved only in IBS-D (p = 0.0006), whereas QoL improved both in IBS-D (p = 0.01) and IBS-M (p = 0.005).

Conclusion

This post hoc analysis showed that the app is useful in all IBS subtypes; thus, it could be used as an effective tool by both general practitioners and patients to manage symptoms in primary care.

Trial registration

Ethical Commission University Hospital of Leuven reference number: S59482. Clinicaltrial.gov reference number: NCT04270487.

The efficacy and real-world effectiveness of a diet low in fermentable oligo-, di-, monosaccharides and polyols in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND & AIMS

A diet low in fermentable oligo-, di-, monosaccharides, and polyols (LFD) has been shown to effectively reduce irritable bowel syndrome (IBS) symptoms. Effects resulting from real-world studies may differ from those seen in efficacy studies because of the diversity of patients in real-world settings. This systematic review and meta-analysis aimed to compare the effect of the LFD on reducing IBS symptoms and improving the quality of life (QoL) in efficacy trials and real-world studies.

METHODS

Major databases, trial registries, dissertations, and journals were systematically searched for studies on the LFD in adults with IBS. Meta-analysis was conducted using a random effects model with standardized mean differences (SMD) and 95% confidence intervals (CI). Outcomes of interest were all patient-reported: stool consistency, stool frequency, abdominal pain, overall symptoms, adequate symptom relief, IBS-specific QoL and adherence to the LFD.

RESULTS

Eleven efficacy and 19 real-world studies were reviewed. The meta-analysis results for abdominal pain (SMD 0.35, 95% CI 0.16 to 0.54) and QoL (SMD 0.23, 95% CI -0.05 to 0.50) showed the LFD was beneficial in efficacy studies with no statistically significant results for stool frequency (SMD 0.71, 95% CI 0.34 to 1.07). Real-world studies found improvements in abdominal pain and QoL. Due to heterogeneity, no meta-analysis was done for stool consistency and overall symptoms. In these outcomes, results were mostly supportive of the LFD, but they were not always statistically significant.

CONCLUSIONS

The results of this systematic review and meta-analysis suggest the LFD improves outcomes compared to a control diet (efficacy studies) or baseline data (real-world studies). Because of diverse study designs and heterogeneity of results, a clear superiority of the LFD over control diets could not be concluded. There are no indications of an efficacy-effectiveness gap for the LFD in adults with IBS.

Effects of a low FODMAP diet on the symptom management of patients with irritable bowel syndrome: a systematic umbrella review with the meta-analysis of clinical trials

A low FODMAP diet (LFD) is a common restrictive diet to manage the symptoms of irritable bowel syndrome (IBS). However, there is no consensus on the alleviating effects of this diet. Herein, a systematic umbrella review with meta-analysis was conducted to investigate the effect of an LFD on IBS symptoms and its secondary outcomes in patients, which were not reported in previous meta-analyses. We performed a systematic literature search in PubMed, Scopus, and ISI Web of Science up to December 2023. The methodological quality of systematic reviews and their included trials was evaluated using AMSTAR 2 and the Cochrane risk of bias, respectively. The certainty of the evidence tool was evaluated using the GRADE approach. The data related to IBS symptoms, quality of life (QoL), microbiome diversity, and stool short-chain fatty acids were extracted. A random-effect (if RCTs ≥ 6) or fixed-effect model (if RCTs < 5) was used to recalculate effect sizes and 95% CIs and report them in both qualitative and quantitative terms (pooled risk ratio, Hedges' g, and weighted mean difference). A total of 658 articles were initially identified, with 11 meta-analyses and 24 RCTs reporting 28 outcomes with 1646 participants included. An LFD significantly affected the clinical improvement of total symptoms according to the IBS-SSS questionnaire (RR: 1.42; 95% CI: 1.02, 1.97; P = 0.04) in all the subtypes of IBS and also had favorable effects on stool consistency (WMD: -0.48; 95% CI: -0.902, -0.07) and frequency (WMD: -0.36; 95% CI: -0.61, -0.10) and some other GI symptoms in both less and more than 4 weeks of diet intervention except for stool consistency, which needed more than 4 weeks of LFD implementation. A significant QoL improvement was observed but not in the anxiety and depression state. Furthermore, some studies showed that an LFD may increase fecal pH and dysbiosis and reduce SCFA and the abundance of Bifidobacterium. In conclusion, an LFD can alleviate symptoms and QoL in IBS patients, although dysbiosis may occur. Considering the low certainty of evidence, strong RCTs with more appropriate designs are needed.

Assessing 'response' to the low-FODMAP diet in irritable bowel syndrome: Should we be reporting harder primary endpoints?

BACKGROUND & AIMS

The low-FODMAP diet (LFD) has become almost synonymous with IBS care, yet the challenges associated with this rigorous therapeutic approach are often underacknowledged. Despite positive outcomes in RCTs, comparator groups frequently exhibit substantial response rates, raising questions about the definition of 'response'. Whilst the assessment of response in drug trials has evolved to utilize the more stringent FDA/EMA primary clinical endpoints, trials of the LFD have not yet followed. The aim of this article is to opine whether the current approach to the measurement of clinical response to the LFD in clinical trials should be reconsidered.

METHODS

A comprehensive literature review of LFD clinical trials from the past decade was conducted, focusing on recorded response metrics for primary clinical endpoints.

RESULTS

While response definitions vary, the 50-point IBS-SSS delta emerged as the predominant metric. Notably, no trials to date have adopted the more stringent primary clinical endpoints used in drug trials. Other response measures included binary response metrics (such as 'adequate clinical response'), changes in visual analogue scales or stool form/output, reductions in abdominal pain, as well as changes the magnitude of the IBS-SSS delta. Whether these metrics correspond to a clinically meaningful improvement for the patient is less clear, and as such aligning patient-clinician expectations can be challenging.

CONCLUSIONS

A paradigm shift in the conceptualization of 'response' coupled with an emphasis on harder clinical endpoints in the context of clinical trials may serve to better justify the trade-off between symptom-improvement and the inherent challenges associated with this burdensome therapeutic approach.

Randomized trial in postprandial functional dyspepsia: Reassurance and diagnostic explanation with or without traditional dietary advice

BACKGROUND

Almost 80% of individuals with functional dyspepsia experience meal-related symptoms and are diagnosed with postprandial distress syndrome (PDS). However, studies evaluating dietary modifications in PDS are sparse. We performed a single-center randomized trial comparing reassurance and diagnostic explanation (RADE) with or without traditional dietary advice (TDA) in PDS.

METHODS

Following a normal upper gastrointestinal endoscopy, individuals with PDS were randomized to a leaflet providing RADE ± TDA; the latter recommending small, regular meals and reducing the intake of caffeine/alcohol/fizzy drinks and high-fat/processed/spicy foods. Questionnaires were completed over 4 weeks, including self-reported adequate relief of dyspeptic symptoms, and the validated Leuven Postprandial Distress Scale (LPDS), Gastrointestinal Symptom Rating Scale, and Nepean Dyspepsia Index for quality of life. The primary endpoint(s) to define clinical response were (i) ≥50% adequate relief of dyspeptic symptoms and (ii) >0.5-point reduction in the PDS subscale of the LPDS (calculated as the mean scores for early satiety, postprandial fullness, and upper abdominal bloating).

KEY RESULTS

Of the 53 patients with PDS, 27 were assigned RADE-alone and 26 to additional TDA. Baseline characteristics were similar between groups, with a mean age of 39 years, 70% female, 83% white British, and coexistent irritable bowel syndrome in 66%. The primary endpoints of (i) adequate relief of dyspeptic symptoms were met by 33% (n = 9) assigned RADE-alone versus 39% (n = 10) with TDA; p-value = 0.70, while (ii) a reduction of >0.5 points in the PDS subscale was met by 37% (n = 10) assigned RADE-alone versus 27% (n = 7) with TDA; p-value = 0.43. Response rates did not differ according to irritable bowel syndrome status. There were no significant between-group changes in the gastrointestinal symptom rating scale and dyspepsia quality of life.

CONCLUSIONS & INFERENCES

This study of predominantly white British patients with PDS found the addition of TDA did not lead to significantly greater symptom reduction compared with RADE alone. Alternate dietary strategies should be explored in this cohort.

Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.

The low FODMAP diet in clinical practice: where are we and what are the long-term considerations?

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) improves functional bowel symptoms and is a second-line dietary management strategy for the treatment of irritable bowel syndrome (IBS). The diet is complex and involves three stages: restriction, reintroduction and personalisation and clinical effectiveness is achieved with dietitian-led education; however, this is not always available. The aim of this review is to provide an update on the evidence for using the low FODMAP diet, with a focus on the impact of FODMAP restriction and reintroduction considering long-term management of IBS in a clinical setting. Randomised controlled trials have assessed symptom response, quality of life, dietary intake and changes to the gut microbiota during FODMAP restriction. Systematic reviews and meta-analyses consistently report that FODMAP restriction has a better symptom response compared with control diets and a network analysis reports the low FODMAP diet is superior to other dietary treatments for IBS. Research focused on FODMAP reintroduction and personalisation is limited and of lower quality, however common dietary triggers include wheat, onion, garlic, pulses and milk. Dietitian-led delivery of the low FODMAP diet is not always available and alternative education delivery methods, e.g. webinars, apps and leaflets, are available but remove the personalised approach and may be less acceptable to patients and may introduce safety concerns in terms of nutritional adequacy. Predicting response to the low FODMAP diet using symptom severity or a biomarker is of great interest. More evidence on less restrictive approaches and non-dietitian-led education delivery methods are needed.

The Role of the FODMAP Diet in IBS

The low FODMAP (fermentable oligosaccharide, disaccharide, monosaccharide, and polyol) diet is a beneficial therapeutic approach for patients with irritable bowel syndrome (IBS). However, how the low FODMAP diet works is still not completely understood. These mechanisms encompass not only traditionally known factors such as luminal distension induced by gas and water but also recent evidence on the role of FOMAPs in the modulation of visceral hypersensitivity, increases in intestinal permeability, the induction of microbiota changes, and the production of short-chain fatty acids (SCFAs), as well as metabolomics and alterations in motility. Although most of the supporting evidence is of low quality, recent trials have confirmed its effectiveness, even though the majority of the evidence pertains only to the restriction phase and its effectiveness in relieving abdominal bloating and pain. This review examines potential pathophysiological mechanisms and provides an overview of the existing evidence on the effectiveness of the low FODMAP diet across various IBS subtypes. Key considerations for its use include the challenges and disadvantages associated with its practical implementation, including the need for professional guidance, variations in individual responses, concerns related to microbiota, nutritional deficiencies, the development of constipation, the necessity of excluding an eating disorder before commencing the diet, and the scarcity of long-term data. Despite its recognized efficacy in symptom management, acknowledging these limitations becomes imperative for a nuanced comprehension of the role of a low FODMAP diet in managing IBS. By investigating its potential mechanisms and evidence across IBS subtypes and addressing emerging modulations alongside limitations, this review aims to serve as a valuable resource for healthcare practitioners, researchers, and patients navigating the intricate landscape of IBS.

A systematic review and meta-analysis of diet and nutrient intake in adults with irritable bowel syndrome

BACKGROUND

Numerous individual and environmental factors including diet may play an important role in the pathophysiology of irritable bowel syndrome (IBS). It is unclear to what degree dietary intake is affected in individuals with IBS. We aimed to perform a systematic review and meta-analysis to summarize dietary intake of adults with IBS and to compare dietary intake between adults with IBS and non-IBS controls.

METHODS

Ovid MEDLINE, Embase, Cochrane, CINAHL, and Scopus were searched through February 2023 for clinical trials and observational studies measuring usual diet in adults with IBS. Pooled weighted averages were estimated for total energy, macronutrient, and micronutrient data. Mean differences (MD) in nutrient intake were estimated for adults with IBS versus non-IBS controls using a random effects model. Heterogeneity was assessed by the inconsistency index (I2).

KEY RESULTS

Sixty-three full-text articles were included in the review of which 29 studies included both IBS and control subjects. Nutrients not meeting the recommended intake level for any dietary reference values in the IBS population were fiber and vitamin D. Meta-regression by female proportion was positively correlated with total fat intake and negatively correlated with carbohydrate intake. Comparisons between participants with IBS and controls showed significantly lower fiber intake in participants with IBS with high heterogeneity (MD: -1.8; 95% CI: -3.0, -0.6; I2 = 85%).

CONCLUSIONS AND INFERENCES

This review suggests that fiber and vitamin D intake is suboptimal in IBS; however, overall dietary intake does not appear to be comprised. Causes and consequences of reduced fiber in IBS deserve further study. Results of this systematic review and meta-analysis suggest that fiber and vitamin D intake is suboptimal in IBS. However, overall intake of other macro- and micronutrients does not appear to be compromised. Causes and consequences of reduced fiber and Vitamin D intake in IBS deserve further study.

Unlocking the potential of low FODMAPs sourdough technology for management of irritable bowel syndrome

Consumption of high FODMAP (Fermentable Oligo-, Di-, and Monosaccharides and Polyols) diet is the leading cause of alteration in the human gut microbiome, thereby, causing irritable bowel syndrome (IBS). Therefore, sourdough technology can be exploited for reduction of FODMAPs in various foods to alleviate the symptoms of IBS. Several microorganisms viz. Pichia fermentans, Lactobacillus fetmentum, Saccharomyces cerevisiae, Torulaspora delbrueckii, Kluyveromyces marxianus etc. have been identified for the production of low FODMAP type II sourdough fermented products. However, more research on regulation of end-product and volatilome profile is required for maximal exploitation of FODMAP-reducing microorganisms. Therefore, the present review is focused on utilisation of lactic acid bacteria and yeasts, alone and in synergy, for the production of low FODMAP sourdough foods. Moreover, the microbial bioprocessing of cereal and non-cereal based low FODMAP fermented sourdough products along with their nutritional and therapeutic benefits have been elaborated. The challenges and future prospects for the production of sourdough fermented low FODMAP foods, thereby, bringing out positive alterations in gut microbiome, have also been discussed.

The Long-Term Effects of a Low-Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols Diet for Irritable Bowel Syndrome Management

Short-term studies indicate that low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diets (LFDs) can improve symptoms for patients with irritable bowel syndrome (IBS). However, long-term (≥6 mo) effectiveness, safety, and sustainability of an LFD are not well understood and remain controversial. The primary purpose of the current review was to consider the published research on the effectiveness, safety, and sustainability of an LFD for patients with IBS. The secondary aim was to develop an infographic for dissemination to outpatient registered dietitian nutritionists and other healthcare professionals who work with patients with IBS. Three electronic databases (PubMed, Scopus, and Web of Science) were searched through December 2022, using the terms irritable bowel syndrome, FODMAP, and long-term. Following article selection, a total of 14 studies were included. Nine of 9 studies reported significant improvements in symptoms, 7 of 7 studies showed significant improvements in bowel habits, 1 of 1 study showed significantly improved disease course, and 6 of 6 studies showed significantly improved quality of life, compared to baseline. One study showed that improvement in gastrointestinal symptoms was significantly correlated with improvements in quality of life. Two of 3 studies and body composition measures indicated that nutritional adequacy was not compromised. Two of 2 studies showed that gut microbiota did not change, but 1 study showed decreased short-chain fatty acids. Adherence rates ranged from 50% to 82%, and 1 study showed that greater adherence was significantly correlated with improved IBS symptoms. Three of 3 studies showed that better adherence to an LFD was associated with improved symptom relief, and 70%-89% of participants reported satisfaction with the LFD for IBS management. The main difficulties reported were the higher expense and adhering to the diet when eating at restaurants, with family and friends, or while traveling. Overall, a long-term LFD for IBS management can be effective, safe, and sustainable.

Managing pain in irritable bowel syndrome: current perspectives and best practice

INTRODUCTION

Irritable bowel syndrome (IBS) is characterized by chronic symptoms (>6 months) of abdominal pain in combination with a disturbed bowel habit. There is an association between the intensity of abdominal pain and the need for health care utilization. A bidirectionally disordered gut-brain interaction is central in the pathophysiology of IBS where a number of factors, gastrointestinal and non-gastrointestinal, can contribute to the illness experience. In order to treat abdominal pain in IBS, mapping these factors in a multidimensional clinical profile is helpful.

AREAS COVERED

This review covers basic epidemiology and pathophysiology of abdominal pain in IBS, the diagnostic approach, and a multidimensional treatment model where the management of abdominal pain is in focus.

EXPERT OPINION

A personalized treatment of abdominal pain in IBS is possible in patients who understand the diagnosis, the potential of therapies used, and where a good continuity in the patient-doctor relationship is established.

Current evidence for dietary therapies in irritable bowel syndrome

PURPOSE OF REVIEW

Diet appears to trigger symptoms in the majority of individuals with irritable bowel syndrome (IBS) and is associated with a reduced quality of life. There has been a recent focus on the role of dietary therapies to manage individuals with IBS. The aim of this review is to discuss the utility of traditional dietary advice (TDA), low-FODMAP diet (LFD) and gluten-free diet (GFD) in IBS.

RECENT FINDINGS

Several recent randomized controlled trials (RCTs) have been published demonstrating the efficacy of the LFD and GFD in IBS, with the evidence base for TDA being predominantly based on clinical experience, with emerging RCTs evaluating TDA. Only one RCT has been published to date comparing TDA, LFD and GFD head to head, with no difference noted between diets in terms of efficacy. However, TDA has been noted to be more patient-friendly and is commonly implemented as a first-line dietary therapy.

SUMMARY

Dietary therapies have been demonstrated to improve symptoms in patients with IBS. In view of insufficient evidence to recommend one diet over another currently, specialist dietetic input in conjunction with patient preference is required to determine implementation of dietary therapies. Novel methods of dietetic delivery are required in view of the lack of dietetic provision to deliver these therapies.

Efficacy of diet restriction with or without probiotic for treatment of patients with IBS-D: Phase I-II clinical trial

BACKGROUND AND AIM

Diet is a major contributor to irritable bowel syndrome (IBS) and is also a powerful tool for treatment of IBS. This study compared two diets and explored the effectiveness of the diets when combined with a probiotic for treatment of IBS-D patients.

METHODS

Phase I, patients were randomized into groups; control, cold/spicy/fried restricted diet (CSF res diet), IgG positive restricted diet (IgG res diet), and a combination both diets (CSF + IgG res diet). Phase II, patients were randomized into IgG res diet + placebo and IgG res diet + probiotic. Both interventions were 12 weeks in duration. Symptom Severity Scale (IBS-D-SSS) and IgG titer were assessed at the beginning and the end of the study.

RESULTS

Totals of 214 and 167 patients completed the two parts of the study, respectively. After intervention, IBS-D-SSS and TIgG grade were significantly improved compared to baseline, with results similar to the control group. In general, there were decreases in IBS-D-SSS and TIgG grade that were significantly different among the groups. There were exceptions; no differences were observed for IBS-D-SSS between the IgG res diet and CSF + IgG res diet, or TIgG grade between the CSF res diet, IgG res diet, and CSF + IgG res diet. However, the CSF res diet and IgG res diet had a synergistic effect that decreased IBS-D-SSS and TIgG titer, with a greater contribution by the IgG res diet. Therefore, we evaluated the IgG res diet with either placebo or probiotic and found that IBS-D-SSS and TIgG grade decreased from baseline. There was a significant decrease in IBS-D-SSS with the probiotic but TIgG grade was not significantly different between the IgG diet + placebo and IgG diet + probiotic diet.

CONCLUSIONS

Both the CSF res diet and IgG res diet improved IBS symptoms and demonstrated synergy, although the IgG res diet had a greater contribution. Further, when intolerant foods cannot be eliminated from a diet, avoiding uncooked, cold, spicy, fried, and alcoholic foods is a superior choice. The IgG res diet combined with Bifidobacteria was the best dietary choice and may function though a non-IgG pathway.

Indian consensus statements on irritable bowel syndrome in adults: A guideline by the Indian Neurogastroenterology and Motility Association and jointly supported by the Indian Society of Gastroenterology

The Indian Neurogastroenterology and Motility Association (INMA), earlier named the Indian Motility and Functional Diseases Association developed this evidence-based practice guidelines for the management of irritable bowel syndrome (IBS). A modified Delphi process was used to develop this consensus containing 28 statements, which were concerning diagnostic criteria, epidemiology, etiopathogenesis and comorbidities, investigations, lifestyle modifications and treatments. Owing to the Coronavirus disease-19 (COVID-19) pandemic, lockdowns and mobility restrictions, web-based meetings and electronic voting were the major tools used to develop this consensus. A statement was regarded as accepted when the sum of "completely accepted" and "accepted with minor reservation" voted responses were 80% or higher. Finally, the consensus was achieved on all 28 statements. The consensus team members are of the view that this work may find use in teaching, patient care, and research on IBS in India and other nations.

A Reduced Tryptophan Diet in Patients with Diarrhoea-Predominant Irritable Bowel Syndrome Improves Their Abdominal Symptoms and Their Quality of Life through Reduction of Serotonin Levels and Its Urinary Metabolites

(1). An essential component of any treatment for patients with irritable bowel syndrome (IBS) is an adequate diet. Currently, a low FODMAP diet is recommended as a first-line therapy, but it does not relieve abdominal discomfort in all patients, and alternative nutritional treatment is required. The purpose of this study was to evaluate the effect of a tryptophan-lowering diet (TRP) on abdominal and mental symptoms in patients with irritable bowel syndrome with predominant diarrhea (IBS-D). (2). The study included 40 patients with IBS-D, and 40 healthy subjects served as a baseline for IBS-D patients, after excluding comorbidities. The TRP intake was calculated using the nutritional calculator. The severity of abdominal symptoms was assessed using the gastrointestinal symptom rating scale (GSRS-IBS). Mental state was assessed using the Hamilton anxiety rating scale (HAM-A), the Hamilton depression rating scale (HAM-D), and the insomnia severity index (ISI). The serum levels of serotonin and melatonin and the urinary excretion of their metabolites 5-hydroxyindoleacetic acid (5-HIAA) and 6-sulfatoxymelatonin (aMT6) were determined by the ELISA method. The severity of symptoms and laboratory data were analyzed before and after a 12 week diet with tryptophan restricted to a daily dose 10 mg per kilogram body weight. (3). Compared to the control group, patients with IBS-D had a higher serum level of serotonin (198.2 ± 38.1 vs. 142.3 ± 36.4 ng/mL; p < 0.001) but a similar level of melatonin (8.6 ± 1.1 vs. 9.4 ± 3.0 pg/mL; p > 0.05). The urinary excretion of 5-HIAA was also higher in patients with IBS-D patients (7.7 ± 1.5 vs. 6.0 ± 1.7 mg/24 h; p < 0.001). After nutritional treatment, both the serum serotonin level and the urinary 5-HIAA excretion significantly decreased (p < 0.001). The severity of the abdominal symptoms and anxiety also decreased, while the HAM-D score and the ISI score remained unchanged (4). Lowering the dietary intake of tryptophan may reduce abdominal complaints and does not alter the mental state of IBS-D patients.

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

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.

Non-pharmacological strategies to treat irritable bowel syndrome: 2022 update

Irritable bowel syndrome (IBS) is a chronic functional disorder characterized by abdominal pain associated with changes in stool frequency or form, in absence of organic disease. The treatment of IBS is often challenging and should be individually adjusted according to the prevalent symptomatology. Pharmacological treatment for IBS with diarrhea includes peripheral opioid agonists, bile acid sequestrants and antibiotics, while IBS with constipation can be treated with soluble fibers, osmotic agents or prokinetics. In case of abdominal pain, the available pharmacological options are antispasmodics, peripheral opioid agonists or antidepressants. Along with pharmacotherapy, non-pharmacological interventions should be considered as they can play an important role in symptom control. The first-line approach includes lifestyle modifications and dietary advice. Microbiota manipulation through probiotics, prebiotics and symbiotics is a widely used strategy, although the evidence upon the most effective among these in specific IBS subtypes is still unclear. Fecal microbiota transplantation is still in experimental phase for IBS, but it is giving promising results. Psychological therapies may be effective in patients with IBS, despite their application can be limited by long duration, high costs and poor patient's acceptance. Alternative medicine approaches, such as acupuncture, body relaxation techniques, dietary supplements or Chinese herbs, have been proposed; however, the evidence upon their efficacy and safety is still controversial.

Diagnostic management of patients reporting symptoms after wheat ingestion

Many patients report symptoms after wheat ingestion experiencing a wide spectrum of clinical manifestations. Three possible diagnoses have been recognized: celiac disease (CD), wheat allergy (WA), and non-celiac (gluten) wheat sensitivity (NCGS/NCWS). CD is a chronic immune-mediated disease of the small bowel caused by exposure to dietary gluten in genetically predisposed individuals, with a prevalence of approximately 1%. It is characterized by mucosal inflammation and atrophy following exposure to gluten and improvement after gluten withdrawal. Food allergies are immunological responses to a food antigen. WA is the expression of an immunologically mediated process that can be immunoglobulin E (IgE) or non-IgE mediated; its many symptoms include urticaria/angioedema, asthma, rhinitis, and anaphylaxis. NCGS/NCWS is characterized by gastrointestinal and/or extra-intestinal symptoms after ingestion of gluten-containing food in subjects not affected by CD or WA. The aim of this review is to help physicians and nutritionists diagnose the cause of symptoms reported after wheat ingestion, thus avoiding patient frustration, inappropriate testing, and incorrect or missed diagnoses. An algorithm for the diagnostic approach in these patients is provided, to help to diagnose CD, WA, NCGS/NCWS or to identify possible functional disorders as the wheat-sensitive irritable bowel syndrome. A personalized approach, regular follow-up, and the help of a skilled healthcare professional are mandatory for patients with symptoms following wheat ingestion is provided. A gluten-free-diet is often recommended for patients with self-reported gluten/wheat-dependent symptoms; for patients with symptoms similar to those of functional diseases while there is evidence that a low-FODMAP diet could be the first option.

Children with functional abdominal pain disorders successfully decrease FODMAP food intake on a low FODMAP diet with modest improvements in nutritional intake and diet quality

BACKGROUND

We sought to determine how a low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet (LFD) affected high FODMAP food intake, nutrient intake, and diet quality in children with functional abdominal pain disorders (FAPD).

METHODS

Children (ages 7-13 years) with Rome IV FAPD began a dietitian-guided LFD. Three-day food records were captured at baseline and 2-3 weeks into the LFD. Intake of high FODMAP foods, energy, macronutrients, micronutrients, food groups, and ultra-processed foods were determined.

KEY RESULTS

Median age of participants was 11 years, and 19/31 (61%) were female. Twenty-eight (90%) decreased high FODMAP food intake on the LFD: overall median (25-75%) high FODMAP foods/day decreased from 5.7 (3.6-7.3) to 2 (0.3-3.7) (p < 0.001). A more adherent subset (n = 22/71%) of participants consumed on average ≤3 high FODMAP foods per day during the LFD. Baseline nutritional intake and quality were generally poor with several micronutrient deficiencies identified. Diet quality improved on the LFD with increased servings of vegetables and protein and decreased consumption of ultra-processed foods, trans-fatty acids, and added sugars. On the LFD, there were significant decreases in total carbohydrates and thiamin (remained within recommended intake) and significant increases in vitamin B6 (p = 0.029), vitamin C (p = 0.019), and vitamin E (p = 0.009). Children more adherent to the LFD further increased vitamin D, magnesium, potassium, and fat servings.

CONCLUSIONS AND INFERENCES

The majority of children with FAPD on a dietitian-led LFD successfully decreased high FODMAP food intake. Children with FAPD on the LFD (vs. baseline) modestly improved micronutrient intake and diet quality.

Diet and irritable bowel syndrome: an update from a UK consensus meeting

There has been a renewed interest in the role of dietary therapies to manage irritable bowel syndrome (IBS), with diet high on the agenda for patients. Currently, interest has focussed on the use of traditional dietary advice (TDA), a gluten-free diet (GFD) and the low FODMAP diet (LFD). A consensus meeting was held to assess the role of these dietary therapies in IBS, in Sheffield, United Kingdom.Evidence for TDA is from case control studies and clinical experience. Randomised controlled trials (RCT) have demonstrated the benefit of soluble fibre in IBS. No studies have assessed TDA in comparison to a habitual or sham diet. There have been a number of RCTs demonstrating the efficacy of a GFD at short-term follow-up, with a lack of long-term outcomes. Whilst gluten may lead to symptom generation in IBS, other components of wheat may also play an important role, with recent interest in the role of fructans, wheat germ agglutinins, as well as alpha amylase trypsin inhibitors. There is good evidence for the use of a LFD at short-term follow-up, with emerging evidence demonstrating its efficacy at long-term follow-up. There is overlap between the LFD and GFD with IBS patients self-initiating gluten or wheat reduction as part of their LFD. Currently, there is a lack of evidence to suggest superiority of one diet over another, although TDA is more acceptable to patients.In view of this evidence, our consensus group recommends that dietary therapies for IBS should be offered by dietitians who first assess dietary triggers and then tailor the intervention according to patient choice. Given the lack of dietetic services, novel approaches such as employing group clinics and online webinars may maximise capacity and accessibility for patients. Further research is also required to assess the comparative efficacy of dietary therapies to other management strategies available to manage IBS.

Diet for Functional Gastrointestinal Disorders/Disorders of Gut-Brain Interaction

Dietary interventions may alleviate symptoms related to functional gastrointestinal disorders, now termed disorders of gut-brain interaction. We reviewed which interventions have high-quality data to support their use in gastroesophageal reflux disease (GERD), functional dyspepsia (FD), irritable bowel syndrome, and chronic idiopathic constipation.

Low FODMAP diet in irritable bowel syndrome: a review of recent clinical trials and meta-analyses

PURPOSE OF REVIEW

The low fermentable oligosaccharides, disaccharides, monosaccharides and polyol (FODMAP) diet is widely used in the dietary management of irritable bowel syndrome (IBS). The aim of this review is to summarize recent evidence regarding the use of the low FODMAP diet in IBS and other gastrointestinal disorders from recent clinical trials and meta-analyses.

RECENT FINDINGS

Several recent systematic reviews and meta-analyses support the use of low FODMAP restriction for global symptoms in IBS in the short term. Uncontrolled follow-up studies show that at least 50% of individuals experience symptom relief following restriction, reintroduction and personalization in the long term. Although evidence from comparative trials in IBS suggests potential benefit of less burdensome approaches (e.g. standard IBS diet and low lactose diet) many studies are insufficiently powered. One established mechanism is colonic gas production that may induce pain signalling measurable in the brain, however altered gastrointestinal epithelial integrity and shifts in microbiome composition and function may also be involved.

SUMMARY

Quality trials of the low FODMAP diet are emerging and have been transformational in supporting the widespread application to IBS management in some areas (e.g. short-term effectiveness), whereas other areas still require considerable improvements in research evidence (e.g. long-term effectiveness, mechanisms and educational delivery).

Current perspectives on irritable bowel syndrome: a narrative review

The pathophysiology of irritable bowel syndrome (IBS) has not yet been fully elucidated. We reviewed articles addressing IBS that have been published in the last 2 years and selected papers related to IBS pathophysiology and treatment. Studies of intestinal bacteria, low-grade mucosal inflammation, and increased mucosal permeability—factors involved in the pathophysiology of IBS—have been conducted. In addition, the involvement of intestinal bacteria in IBS pathology has been clarified; many studies of treatments related to intestinal bacteria have been reported. Moreover, several studies address the effect on IBS of antidepressants and psychotherapy through the brain–gut axis. The contents of these papers are described in this narrative review.

Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a heterogeneous disorder of gut-brain interaction (DGBI) maintained by interacting biological, psychological, and social processes. Interestingly, there are two contrasting yet evidence-based treatment approaches for reducing IBS symptoms: exclusion diets such as those low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and exposure-based cognitive-behavioural therapy (CBT). Exclusion diets recommend patients avoid foods thought to be symptom-inducing, whereas exposure-based CBT encourages patients to expose themselves to foods.

AIMS

To address the paradox of conceptually opposite exclusion diets and exposure-based CBT for IBS.

METHODS

In this conceptual review, we describe the rationale, practical implementation, evidence base and strengths and weaknesses of each treatment. We conducted up-to-date literature search concerning the low FODMAP diet and CBT, and performed a secondary analysis of a previously conducted trial to illustrate a key point in our review.

RESULTS

The low FODMAP diet has demonstrated efficacy, but problems with adherence, nutritional compromise, and heightened gastrointestinal-specific anxiety raise caution. Exposure-based CBT has demonstrated efficacy with substantial evidence for gastrointestinal-specific anxiety as a key mechanism of action. Mediation analysis also showed that increased FODMAP intake mediated decreased symptom severity in exposure-based CBT. However, there is minimal evidence supporting which treatment "works best for whom" and how these approaches could be best integrated.

CONCLUSIONS

Even though exclusion diets and exposure-based CBT are conceptually opposite, they each have proven efficacy. Clinicians should familiarise themselves with both treatments. Further research is needed on predictors, mechanisms and moderators of treatment outcomes.

How to Implement the 3-Phase FODMAP Diet Into Gastroenterological Practice

BACKGROUND/AIMS

The 3-phase fermentable oligo-, di-, mono-saccharides, and polyols (FODMAP) diet has shown a high level of efficacy in irritable bowel syndrome, largely based on dietitian delivered education. However, access to dietitians can be limited, and challenges exist when applying the diet to a wide range of cultures, such as limited FODMAP analysis of local foods. This review aims to discuss ways to optimally use the FODMAP diet in practice in a wide range of cultures, directed at gastroenterologists from a dietitian's perspective.

METHODS

Recent literature was analysed via search databases including Medline, CINAHL, PubMed and Scopus.

RESULTS

The dietetic process involves detailed assessment and follow-up through the 3 stages of the FODMAP diet (restriction, re-introduction, and long-term maintenance). Emerging evidence suggests the diet can be delivered by other health professionals such as the gastroenterologist or nurse, but training on how to do so successfully would be needed. Self-guided approaches through use of technology or specialised food delivery services may be an alternative when dietitians are not available, but efficacy data is limited. Regardless of delivery mode, nutritional and psychological risks of the diet must be mitigated. Additionally, culturally appropriate education must be provided, with accommodations necessary when the FODMAP content of local foods are unknown.

CONCLUSION

While the diet has shown improved irritable bowel syndrome outcomes across studies, it is important to acknowledge the essential role of dietitians in implementing, tailoring, and managing the diet to achieve the best outcome for each individual.

Efficacy of a Restrictive Diet in Irritable Bowel Syndrome: A Systematic Review and Network Meta-analysis

BACKGROUND/AIMS

Dietary factors can aggravate the symptoms of irritable bowel syndrome (IBS). Many IBS patients try restrictive diets to relieve their symptoms, but the types of diets with an exacerbating factor are unknown. Therefore, this paper reports the results of a systematic review and network meta-analysis of randomized-controlled trials (RCTs) reviewing the efficacy of food restriction diets in IBS.

METHODS

The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov databases were searched until July 21, 2021, to retrieve RCTs assessing the efficacy of restriction diets in adults with IBS. Two independent reviewers performed the eligibility assessment and data abstraction. RCTs that evaluated a restriction diet versus a control diet and assessed the improvement in global IBS symptoms were included. These trials reported a dichotomous assessment of the overall response to therapy.

RESULTS

A total of 1,949 citations were identified. After full-text screening, 14 RCTs were considered eligible for the systematic review and network meta-analysis. A starch- and sucrose-reduced diet and a diet with low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) showed significantly better results than a usual diet. Symptom flare-ups in patients on a gluten- free diet were also significantly lower than in those on high-gluten diets.

CONCLUSIONS

These findings showed that the starch- and sucrose-reduced, low FODMAP, and gluten-free diets had superior effects in reducing IBS symptoms. Further studies, including head-to-head trials will be needed to establish the effectiveness of dietary restrictions on IBS symptoms.

Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

Irritable bowel syndrome with diarrhoea (IBS-D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS-D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work-up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS-D and FDr. In terms of diagnosis, the consensus supports a symptom-based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C-reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo-, di-, monosaccharides and polyols, gut-directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5-hydroxytryptamine-3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS-D and FDr.

Gastrointestinal effects of diets low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols

PURPOSE OF REVIEW

Food ingestion is an exacerbator of gastrointestinal symptoms, regardless of origin. Sufferers mistakenly assume that they have suffered an allergic reaction to a given food. Although classical IgE-mediated allergic reactions are rarely culpable, evidence for a role for intolerance to certain carbohydrates in irritable bowel syndrome (IBS) and related conditions increases. This review assesses the status of a commonly implicated group of poorly absorbed carbohydrates (fermentable oligosaccharides, disaccharides, monosaccharides and polyols - FODMAPs) in gastrointestinal pathophysiology.

RECENT FINDINGS

Although evidence of efficacy for low FODMAP diets in IBS accumulates, the magnitude of this effect has declined in recent studies. Comparisons to other dietary approaches have revealed conflicting results; some suggest superiority, others find parity. Concerns had been raised regarding long-term nutritional, psychological and microbiological impacts of FODMAP restriction; providing that the diet is administered in the recommended manner, these do not appear to be clinically important. The mechanisms whereby FODMAPs cause gastrointestinal symptoms continue to be explored.

SUMMARY

FODMAPS induce gastrointestinal symptoms in susceptible individuals and their restriction provides clinical benefits. The magnitude of these benefits, the superiority of FODMAP restriction over other dietary approaches and the mechanisms of its effects continue to be defined.

The Role of Food in the Treatment of Bowel Disorders: Focus on Irritable Bowel Syndrome and Functional Constipation

Irritable bowel syndrome (IBS) and functional constipation (FC) are among the most common disorders of gut-brain interaction, affecting millions of individuals worldwide. Most patients with disorders of gut-brain interaction perceive food as a trigger for their gastrointestinal symptoms, and specific dietary manipulations/advice have now been recognized as a cornerstone therapeutic option for IBS and FC. We discuss in detail the 2 most common dietary interventions used for the management of IBS-general dietary advice based on the National Institute for Health and Care Excellence guidelines and a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). We summarize the literature around the possible mechanisms of FODMAP-mediated IBS pathophysiology, the current 3-step, top-down approach of administering a low FODMAP diet (LFD) (restriction phase, followed by reintroduction and personalization), the efficacy data of its restriction and personalization phases, and possible biomarkers for response to an LFD. We also summarize the limitations and challenges of an LFD along with the alternative approach to administering an LFD (e.g., bottom-up). Finally, we discuss the available efficacy data for fiber, other dietary interventions (e.g., Mediterranean diet, gluten-free diet, and holistic dietary interventions), and functional foods (e.g., kiwifruit, rhubarb, aloe, and prunes) in the management of IBS and FC.

Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis

OBJECTIVE

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is recommended for irritable bowel syndrome (IBS), if general lifestyle and dietary advice fails. However, although the impact of a low FODMAP diet on individual IBS symptoms has been examined in some randomised controlled trials (RCTs), there has been no recent systematic assessment, and individual trials have studied numerous alternative or control interventions, meaning the best comparator is unclear. We performed a network meta-analysis addressing these uncertainties.

DESIGN

We searched the medical literature through to 2 April 2021 to identify RCTs of a low FODMAP diet in IBS. Efficacy was judged using dichotomous assessment of improvement in global IBS symptoms or improvement in individual IBS symptoms, including abdominal pain, abdominal bloating or distension, and bowel habit. Data were pooled using a random effects model, with efficacy reported as pooled relative risks (RRs) with 95% CIs, and interventions ranked according to their P-score.

RESULTS

We identified 13 eligible RCTs (944 patients). Based on failure to achieve an improvement in global IBS symptoms, a low FODMAP diet ranked first vs habitual diet (RR of symptoms not improving=0.67; 95% CI 0.48 to 0.91, P-score=0.99), and was superior to all other interventions. Low FODMAP diet ranked first for abdominal pain severity, abdominal bloating or distension severity and bowel habit, although for the latter it was not superior to any other intervention. A low FODMAP diet was superior to British Dietetic Association (BDA)/National Institute for Health and Care Excellence (NICE) dietary advice for abdominal bloating or distension (RR=0.72; 95% CI 0.55 to 0.94). BDA/NICE dietary advice was not superior to any other intervention in any analysis.

CONCLUSION

In a network analysis, low FODMAP diet ranked first for all endpoints studied. However, most trials were based in secondary or tertiary care and did not study effects of FODMAP reintroduction and personalisation on symptoms.

AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome: Expert Review

DESCRIPTION

Irritable bowel syndrome (IBS) is a commonly diagnosed gastrointestinal disorder that can have a substantial impact on quality of life. Most patients with IBS associate their gastrointestinal symptoms with eating food. Mounting evidence supports dietary modifications, such as the low-fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) diet, as a primary treatment for IBS symptoms. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update (CPU) is to provide best practice advice statements, primarily to clinical gastroenterologists, covering the role of diet in IBS treatment.

METHODS

This expert review was commissioned and approved by the AGA CPU Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPU Committee and external peer review through standard procedures of Gastroenterology. The best practice advice statements were drawn from reviewing existing literature combined with expert opinion to provide practical advice on the role of diet in treating patients with IBS. Because this was not a systematic review, formal rating of the quality of evidence or strength of the presented considerations was not performed. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Dietary advice is ideally prescribed to patients with IBS who have insight into their meal-related gastrointestinal symptoms and are motivated to make the necessary changes. To optimize the quality of teaching and clinical response, referral to a registered dietitian nutritionist (RDN) should be made to patients who are willing to collaborate with a RDN and patients who are not able to implement beneficial dietary changes on their own. If a gastrointestinal RDN is not available, other resources can assist with implementation of diet interventions. BEST PRACTICE ADVICE 2: Patients with IBS who are poor candidates for restrictive diet interventions include those consuming few culprit foods, those at risk for malnutrition, those who are food insecure, and those with an eating disorder or uncontrolled psychiatric disorder. Routine screening for disordered eating or eating disorders by careful dietary history is critical because they are common and often overlooked in gastrointestinal conditions. BEST PRACTICE ADVICE 3: Specific diet interventions should be attempted for a predetermined length of time. If there is no clinical response, the diet intervention should be abandoned for another treatment alternative, for example, a different diet, medication, or other form of therapy. BEST PRACTICE ADVICE 4: In preparation for a visit with a RDN, patients should provide dietary information that will assist in developing an individualized nutrition care plan. BEST PRACTICE ADVICE 5: Soluble fiber is efficacious in treating global symptoms of IBS. BEST PRACTICE ADVICE 6: The low-FODMAP diet is currently the most evidence-based diet intervention for IBS. Healthy eating advice as described by the National Institute of Health and Care Excellence Guidelines, among others, also offers benefit to a subset of patients with IBS. BEST PRACTICE ADVICE 7: The low-FODMAP diet consists of the following 3 phases: 1) restriction (lasting no more than 4-6 weeks), 2) reintroduction of FODMAP foods, and 3) personalization based on results from reintroduction. BEST PRACTICE ADVICE 8: Although observational studies found that most patients with IBS improve with a gluten-free diet, randomized controlled trials have yielded mixed results. BEST PRACTICE ADVICE 9: There are limited data showing that selected biomarkers can predict response to diet interventions in patients with IBS, but there is insufficient evidence to support their routine use in clinical practice.

The Effect of Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Meals on Transient Lower Esophageal Relaxations (TLESR) in Gastroesophageal Reflux Disease (GERD) Patients with Overlapping Irritable Bowel Syndrome (IBS)

A randomized crossover study in eight patients (6 F, age 57 ± 13) with overlapping GERD-IBS (non-constipation) was conducted to evaluate the effects of rice noodle vs. wheat noodle meals for breakfast and lunch on postprandial TLESR, intestinal gas production, and GERD/GI symptoms. Results: Wheat ingestion was significantly associated with more frequent TLESR after lunch than rice (5.0 ± 0.7 vs. 1.9 ± 0.3 times/2 h, p = 0.01). After lunch, wheat ingestion was significantly associated with higher H2 and CH4 levels compared to rice ingestion (p < 0.05), while H2 and CH4 levels before lunch were similar (p > 0.05). The area under curve of H2 concentration until 2 h after lunch significantly correlated with the TLESR number (r = 0.69, p = 0.04). Postprandial regurgitation (2.9 ± 1.2 vs. 0.4 ± 0.2), bloating (7.0 ± 0.4 vs. 3.1 ± 0.9), satiety (7.7 ± 0.4 vs. 3.5 ± 0.9), and belching (3.8 ± 1.2 vs. 1.1 ± 0.6) symptom scores were significantly greater after wheat compared to rice noodle ingestion (p < 0.05). Conclusion: Wheat noodle meals, part of a high FODMAP diet, induced a higher frequency of TLESRs, a higher GERD, and higher upper-GI symptom scores than rice noodle meals, part of a low FODMAP diet, in patients with overlapping IBS-GERD. These effects were associated with more intestinal gas production. Thus, a low FODMAP diet may relieve GERD symptoms in GERD patients with overlapping IBS.

Diet as a therapeutic tool in chronic gastrointestinal disorders: Lessons from the FODMAP journey

BACKGROUND AND AIM

Diet is a powerful tool in the management of gastrointestinal disorders, but developing diet therapies is fraught with challenge. This review discusses key lessons from the FODMAP diet journey.

METHODS

Published literature and clinical experience were reviewed.

RESULTS

Key to designing a varied, nutritionally adequate low-FODMAP diet was our accurate and comprehensive database of FODMAP composition, made universally accessible via our user-friendly, digital application. Our discovery that FODMAPs coexist with gluten in cereal products and subsequent gluten/fructan challenge studies in nonceliac gluten-sensitive populations highlighted issues of collinearity in the nutrient composition of food and confirmation bias in the interpretation of dietary studies. Despite numerous challenges in designing, funding, and executing dietary randomized controlled trials, efficacy of the low-FODMAP diet has been repeatedly demonstrated, and confirmed by real-world experience, giving this therapy credibility in the eyes of clinicians and researchers. Furthermore, real-world application of this diet saw the evolution of a safe and effective three-phased approach. Specialist dietitians must deliver this diet to optimize outcomes as they can target and tailor the therapy and to mitigate the key risks of compromising nutritional adequacy and precipitating disordered eating behaviors, skills outside the gastroenterologist's standard tool kit. While concurrent probiotics are ineffective, specific fiber supplements may improve short-term and long-term outcomes.

CONCLUSIONS

The FODMAP diet is highly effective, but optimal outcomes are contingent on the involvement of a gastroenterological dietitian who can assess, educate, and monitor patients and manage risks associated with implementation of this restrictive diet.

Long-term personalized low FODMAP diet improves symptoms and maintains luminal Bifidobacteria abundance in irritable bowel syndrome

BACKGROUND

Short-term trials demonstrate the low FODMAP diet improves symptoms of irritable bowel syndrome (IBS) but impacts nutrient intake and the gastrointestinal microbiota. The aim of this study was to investigate clinical symptoms, nutrient intake, and microbiota of patients with IBS 12 months after starting a low FODMAP diet.

METHODS

Participants enrolled in a previous short-term clinical trial and who had been through structured FODMAP restriction, reintroduction, and personalization were invited to participate in a follow-up study at one time point at 12 months. Gastrointestinal symptoms, stool output, dietary intake, and quality of life were recorded. Stool samples were collected and analyzed for microbiota (qPCR) and short-chain fatty acids (SCFA). Data were compared with baseline (prior to any intervention in the original clinical trial) using non-parametric statistics.

KEY RESULTS

Eighteen participants were included in the study. Adequate relief of symptoms occurred in 5/18 (28%) at baseline and increased to 12/18 (67%) following long-term personalized low FODMAP diet (p = 0.039). There was a reduction in IBS-SSS total score between baseline (median 227, IQR 99) and long term (154, 89; p < 0.001). Bifidobacteria abundance was not different between baseline (median 9.29 log10 rRNA genes/g, IQR 1.45) and long term (9.20 log10 rRNA genes/g, 1.41; p = 0.766, q = 0.906); however, there were lower concentrations of total SCFA, acetate, propionate, and butyrate.

CONCLUSIONS

In this long-term analysis, two thirds of patients reported adequate relief of symptoms after 12 months of personalized low FODMAP diet that did not result in differences from baseline in Bifidobacteria. FODMAP reintroduction and personalization may normalize some of the effects of short-term FODMAP restriction.