All FODMAPs Aren't Created Equal: Results of a Randomized Reintroduction Trial in Patients With Irritable Bowel Syndrome.

BACKGROUND & AIMS: A diet low in fermentable oligo, di, monosaccharides, and polyols (FODMAPs) is one of the recommended management strategies for irritable bowel syndrome (IBS). However, while effective, adherence to restricting dietary FODMAPs can be challenging and burdensome. The question remains whether limiting all FODMAPs during the restrictive phase of the diet is necessary for symptomatic improvement in the dietary treatment of IBS, or if targeting selected groups of FODMAPs for restriction is sufficient for clinical response. Our study aimed to determine which individual FODMAPs are most likely to lead to symptom generation in patients with IBS who have improved with fodmap restriction. METHODS: Patients meeting Rome IV criteria for IBS were invited to participate in a 12-week study to identify individual FODMAP sensitivities. Those subjects who demonstrated symptom improvement after a 2- to 4-week open-label FODMAP elimination period were recruited to a 10-week blinded-phased FODMAP reintroduction phase of 7 days for each FODMAP. Throughout the study period, daily symptom severity (0-10 point numerical rating system) was recorded. A mixed effect statistical analysis model was used. RESULTS: Between 2018 and 2020, 45 subjects were enrolled. Twenty-five subjects improved with FODMAP elimination, and 21 patients continued into the reintroduction phase of the study. Fructans and galacto-oligosaccharides (GOS) both were associated with worsened abdominal pain (P = .007 and P = .04, respectively). GOS were associated with an increase in bloating (P = 03). Both bloating and abdominal pain worsened throughout the study, regardless of the FODMAP reintroduction (P = .006). CONCLUSION: Our results suggest that the reintroduction of select FODMAPs may be responsible for symptom generation in patients with IBS who have responded to a low FODMAP diet, and provide a strong rationale for performing a future trial comparing the treatment effects of a limited low-FODMAP diet and a standard low-FODMAP diet. CLINICALTRIALS: GOV: NCT03052439.

Is a Simplified, Less Restrictive Low FODMAP Diet Possible? Results from a Double-Blind, Pilot Randomized Controlled Trial.

A low fermentable oligo-, mono-, di-saccharides, and polyols (FODMAPs) diet (LFD) is the most evidence-based dietary therapy for patients with irritable bowel syndrome (IBS).1 However, the current step-down approach to the LFD has significant limitations including being costly, complex, time-consuming, and associated with reduced dietary intake of some micronutrients.2-4 Recently, a step-up approach has been proposed that restricts only a limited number of FODMAPs initially, evaluating symptom response and restricting additional FODMAPs only if necessary.2,5,6 In a double-blind trial, fructans and galacto-oligosaccharides were found to be the most likely FODMAP subgroups to trigger IBS symptoms.7 To date, no study has compared the efficacy of a traditional LFD restriction phase with a more targeted or simplified restriction phase. In a double-blind, pilot-feasibility randomized controlled trial, we compared the efficacy of a 4-week FODMAP-simple restriction phase (eliminating solely fructans and galactooligosaccharides) and a traditional LFD restriction phase in patients with IBS with diarrhea (IBS-D) (ClinicalTrials.gov registration number NCT05831306).

Percutaneous electrical nerve field stimulation for adolescents with irritable bowel syndrome: Cost-benefit and cost-minimization analysis.

Abdominal pain drives significant cost for adolescents with irritable bowel syndrome (IBS). We performed an economic analysis to estimate cost-savings for patients' families and healthcare insurance, and health outcomes, based on abdominal pain improvement with percutaneous electrical nerve field stimulation (PENFS) with IB-Stim® (Neuraxis). We constructed a Markov model with a 1-year time horizon comparing outcomes and costs with PENFS versus usual care without PENFS. Clinical outcomes were derived from a sham-controlled double-blind trial of PENFS for adolescents with IBS. Costs/work-productivity impact for parents were derived from appropriate observational cohorts. PENFS was associated with 18 added healthy days over 1 year of follow-up, increased annual parental wages of $5,802 due to fewer missed work days to care for the child, and $4744 in cost-savings to insurance. Percutaneous electrical field nerve stimulation for adolescents with IBS appears to yield significant cost-savings to patients' families and insurance.

A Randomized Pilot Study to Compare the Effectiveness of a Low FODMAP Diet vs Psyllium in Patients With Fecal Incontinence and Loose Stools.

INTRODUCTION: The aim of the study was to compare the effectiveness of a low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diet (LFD) vs psyllium on the frequency and severity of fecal incontinence (FI) episodes in patients with loose stools. METHODS: This was a single-center, randomized pilot trial of adult patients with FI (Rome III) with at least 1 weekly FI episode associated with loose stool. Eligible patients were randomized to 4 weeks of either a dietitian-led LFD or 6 g/d psyllium treatment. RESULTS: Forty-three subjects were randomized from October 2014 to May 2019. Thirty-seven patients completed the study (19 LFD and 18 psyllium). There was no statistically significant difference in the proportion of treatment responders (>50% reduction in FI episodes compared with baseline) for treatment weeks 1-4 (LFD 38.9%, psyllium 50%, P = .33). Compared with baseline, mean fecal incontinence severity index score significantly improved with LFD (39.4 vs 32.6, P = .02) but not with psyllium (35.4 vs 32.1, P = .29). Compared with baseline values, the LFD group reported improvements in fecal incontinence quality of life coping/behavior, depression/self-perception, and embarrassment subscales. The psyllium group reported improvement in incontinence quality of life coping/behavior. DISCUSSION: In this pilot study, there was no difference in the proportion of patients who reported a 50% reduction of FI episodes with the LFD or psyllium. Subjects in the psyllium group reported a greater reduction in overall FI episodes, whereas the LFD group reported consistent improvements in FI severity and quality of life. Further work to understand these apparently discrepant results are warranted but the LFD and psyllium seem to provide viable treatment options for patients with FI and loose stools.

Utilization of Dietitians in the Management of Irritable Bowel Syndrome by Members of the American College of Gastroenterology.

INTRODUCTION: The aim of this study was to identify benefits and barriers to using a gastroenterology (GI) dietitian for irritable bowel syndrome (IBS) care. METHODS: A 25-question survey was electronically distributed to the members of the American College of Gastroenterology. Information pertaining to demographics, barriers, and values to using a GI dietitian for IBS patient care was collected. RESULTS: Two hundred seventy-nine survey responses were collected. Although 56% of the GI providers feel they are trained to provide nutrition education, almost half (46%) sometimes, rarely, or never provided information to aid menu planning, label reading, or grocery shopping, and 77% spent ≤10 minutes for nutrition counseling. Of those with access to a local dietitian, 91% strongly agreed or agreed that having access to a GI dietitian would help them manage their IBS patient care more effectively, but 42% lack access to a local GI dietitian. DISCUSSION: Our survey identified gaps in nutrition-based interventions for IBS care.

Comparing Costs and Outcomes of Treatments for Irritable Bowel Syndrome With Diarrhea: Cost-Benefit Analysis.

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most expensive gastroenterological conditions and is an ideal target for developing a value-based care model. We assessed the comparative cost-benefit of treatments for IBS with diarrhea (IBS-D), the most common IBS subtype from insurer and patient perspectives. METHODS: We constructed a decision analytic model assessing trade-offs among guideline-recommended and recently FDA-approved drugs, supplements, low FODMAP diet, cognitive behavioral therapy (CBT). Outcomes and costs were derived from systematic reviews of clinical trials and national databases. Health-gains were represented using quality-adjusted life years (QALY). RESULTS: From an insurer perspective, on-label prescription drugs (rifaximin, eluxadoline, alosetron) were significantly more expensive than off-label treatments, low FODMAP, or CBT. Insurer treatment preferences were driven by average wholesale prescription drug prices and were not affected by health gains in sensitivity analysis within standard willingness-to-pay ranges up to $150,000/QALY-gained. From a patient perspective, prescription drug therapies and neuromodulators appeared preferable due to a reduction in lost wages due to IBS with effective therapy, and also considering out-of-pocket costs of low FODMAP food and out-of-pocket costs to attend CBT appointments. Comparative health outcomes exerted influence on treatment preferences from a patient perspective in cost-benefit analysis depending on a patients' willingness-to-pay threshold for additional health-gains, but health outcomes were less important than out-of-pocket costs at lower willingness-to-pay thresholds. CONCLUSIONS: Costs are critical determinants of IBS treatment value to patients and insurers, but different costs drive patient and insurer treatment preferences. Divergent cost drivers appear to explain misalignment between patient and insurer IBS treatment preferences in practice.

Exploratory Comparative Effectiveness Trial of Green Kiwifruit, Psyllium, or Prunes in US Patients With Chronic Constipation.

INTRODUCTION: Psyllium and prunes are proven treatments for chronic constipation (CC). Asian studies suggest that kiwifruit may also benefit CC symptoms. We report a partially randomized, comparative effectiveness trial evaluating kiwifruit, psyllium, and prunes in US patients with CC. METHODS: Adults with CC at a US medical center were randomized to 3 natural treatments. Eligible patients had ≤3 complete spontaneous bowel movements (CSBMs) per week and were partially randomized to green kiwifruit (2/d), prunes (100 g/d), or psyllium (12 g/d) for 4 weeks. The primary endpoint was the proportion of patients in each group reporting an increase of ≥1 CSBM per week compared with baseline for at least 2 of 4 treatment weeks. Key secondary outcomes included stool frequency, stool consistency, and straining assessed daily. Treatment satisfaction and adverse events (AEs) were also measured. Standard statistical methods were used, and a P < 0.05 was considered significant. RESULTS: Seventy-nine patients with CC (mean age = 42.7 years, 87% female, and 77% white) were partially randomized. Complete data were available for 75 patients (kiwifruit 29, prunes 24, and psyllium 22). For the primary endpoint, proportions of CSBM responders were similar for the treatments. For secondary outcomes comparing treatment weeks 3 and 4 to baseline, there was a significant increase in weekly CSBM rate with all 3 treatments (P ≤ 0.003); stool consistency significantly improved with kiwifruit (P = 0.01) and prunes (P = 0.049); and straining significantly improved with kiwifruit (P = 0.003), prunes (P < 0.001), and psyllium (P = 0.04). Patients randomized to the kiwifruit group reported significant improvement in bloating scores (P = 0.02). AEs were most common with psyllium and least common with kiwifruit. At the end of treatment, a smaller proportion of patients were dissatisfied with kiwifruit compared with prunes or psyllium (P = 0.02). DISCUSSION: Kiwifruit, prunes, and psyllium improve constipation symptoms in patients with CC. Kiwifruit was associated with the lowest rate of AEs and dissatisfaction with therapy.

Contrasting Clinician and Insurer Perspectives to Managing Irritable Bowel Syndrome: Multilevel Modeling Analysis.

INTRODUCTION: Insurance coverage is an important determinant of treatment choice in irritable bowel syndrome (IBS), often taking precedence over desired mechanisms of action or patient goals/values. We aimed to determine whether routine and algorithmic coverage restrictions are cost-effective from a commercial insurer perspective. METHODS: A multilevel microsimulation tracking costs and outcomes among 10 million hypothetical moderate-to-severe patients with IBS was developed to model all possible algorithms including common global IBS treatments (neuromodulators; low fermentable oligo-, di-, and mono-saccharides, and polyols; and cognitive behavioral therapy) and prescription drugs treating diarrhea-predominant IBS (IBS-D) or constipation-predominant IBS (IBS-C) over 1 year. RESULTS: Routinely using global IBS treatments (central neuromodulator; low fermentable oligo-, di-, and mono-saccharides, and polyols; and cognitive behavioral therapy) before US Food and Drug Administration-approved drug therapies resulted in per-patient cost savings of $9,034.59 for IBS-D and $2,972.83 for IBS-C over 1 year to insurers, compared with patients starting with on-label drug therapy. Health outcomes were similar, regardless of treatment sequence. Costs varied less than $200 per year, regardless of the global IBS treatment order. The most cost-saving and cost-effective IBS-D algorithm was rifaximin, then eluxadoline, followed by alosetron. The most cost-saving and cost-effective IBS-C algorithm was linaclotide, followed by either plecanatide or lubiprostone. In no scenario were prescription drugs routinely more cost-effective than global IBS treatments, despite a stronger level of evidence with prescription drugs. These findings were driven by higher prescription drug prices as compared to lower costs with global IBS treatments. DISCUSSION: From an insurer perspective, routine and algorithmic prescription drug coverage restrictions requiring failure of low-cost behavioral, dietary, and off-label treatments appear cost-effective. Efforts to address insurance coverage and drug pricing are needed so that healthcare providers can optimally care for patients with this common, heterogenous disorder.

Irritable Bowel Syndrome: Food as a Friend or Foe?

Irritable bowel syndrome (IBS) affects 10% to 15% of the population and often is difficult to treat with available pharmacologic agents. Dietary therapies for IBS are of particular interest because up to 90% of IBS patients exclude certain foods to improve their gastrointestinal symptoms. Among the available dietary interventions for IBS, the low FODMAP diet has the greatest evidence for efficacy. Although dietary therapies rapidly are becoming first-line treatment of IBS, gastroenterologists need to be aware of the negative effects of prescribing restrictive diets and red flag symptoms of maladaptive eating patterns.

Pharmacologic, Dietary, and Psychological Treatments for Irritable Bowel Syndrome With Constipation: Cost Utility Analysis.

Introduction. Irritable bowel syndrome (IBS) is the most common gastroenterology referral and one of the most common gastrointestinal complaints in primary care. We performed a cost-utility analysis of the most common treatments available in general practice for IBS with constipation (IBS-C), the most expensive IBS subtype. Methods. We developed a decision analytic model evaluating guideline-recommended and Food and Drug Administration-approved drugs, supplements, and dietary/psychological interventions. Model inputs were derived from "global symptom improvement" outcomes in systematic reviews of clinical trials. Costs were derived from national datasets. Analysis was performed with a 1-year time horizon from patient and payer perspectives. We analyzed a prototypical managed-care health plan with no cost-sharing to the patient. Results. From a payer perspective, global IBS treatments (including low FODMAP, cognitive behavioral therapy [CBT], neuromodulators), which are not specific to the IBS-C bowel subtype were less expensive than on-label prescription drug treatments. From a patient perspective, on-label prescription drug treatment with linaclotide was the least expensive treatment strategy. Drug prices and costs to manage untreated IBS-C were most important determinants of payer treatment preferences. Effects of treatment on missed work-days and need for repeated appointments to complete treatment were the most important determinants of treatment preference to patients. Discussion. Due mostly to prescription drug prices, neuromodulators, low FODMAP, and CBT appear cost-effective compared to on-label drug treatments from a payer perspective in cost-utility analysis. These findings may explain common treatment barriers in clinical practice.

Low-FODMAP Diet for Irritable Bowel Syndrome: What We Know and What We Have Yet to Learn.

Irritable bowel syndrome (IBS) is the most prevalent of gastrointestinal (GI) conditions, affecting millions of people worldwide. Given that most IBS patients associate their GI symptoms with eating food, specific dietary manipulation has become an attractive treatment strategy. A diet low in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) has generated the greatest level of scientific and clinical interest. Overall, 52-86% of patients report significant improvement of their IBS symptoms with elimination of dietary FODMAPs. Patients who experience symptom improvement with FODMAP elimination should undergo a structured reintroduction of foods containing individual FODMAPs to determine sensitivities and allow for personalization of the diet plan. This review discusses the literature surrounding the administration of the low-FODMAP diet and its efficacy in the treatment of IBS.

The Impact of a 4-Week Low-FODMAP and mNICE Diet on Nutrient Intake in a Sample of US Adults with Irritable Bowel Syndrome with Diarrhea.

BACKGROUND: A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) has gained increasing acceptance for the treatment of irritable bowel syndrome but safety concerns have been raised regarding nutritional adequacy. Changes in nutrient intake during the elimination phase of the low-FODMAP diet remain predominantly unknown. OBJECTIVE: To determine changes in the mean reported daily nutrient content before and after 4 weeks of a low-FODMAP diet vs modified National Institute for Health and Clinical Excellence (mNICE) dietary intervention and to identify nutritional inadequacies based on comparison to the Dietary Reference Intakes in patients with irritable bowel syndrome-diarrhea subtype. DESIGN: Post hoc analysis of a randomized controlled trial entailing a 4-week trial period comparing the low-FODMAP and mNICE diets. PARTICIPANTS AND SETTING: A total of 78 patients (41 low FODMAP and 37 mNICE) meeting the Rome III criteria for irritable bowel syndrome-diarrhea subtype were consecutively recruited from gastroenterology and primary care clinics at the University of Michigan Medical Center between October 2012 and November 2015. METHODS: Participants randomized to the low-FODMAP arm were instructed to decrease their dietary intake of FODMAPs, whereas participants randomized to the mNICE intervention arm were instructed to eat small frequent meals, avoid trigger foods, and avoid excess alcohol and caffeine. MAIN OUTCOME MEASURES: Post hoc evaluation for presence of micronutrient deficiencies per Dietary Reference Intakes when implementing low-FODMAP vs mNICE dietary interventions. Dietary intake was analyzed via 3-day food diaries at baseline and during the final week of the assigned diet. STATISTICAL ANALYSES PERFORMED: A post hoc analysis utilizing either a t test or χ2 analysis was conducted between before and after data. RESULTS: Both diets resulted in fewer daily kilocalories consumed, fewer number of daily meals consumed, and less daily carbohydrate intake. Among the patients following the low-FODMAP diet, there was a statistically significant decrease from baseline in several micronutrients, which was not observed in the mNICE cohort. However, these differences in the low-FODMAP group remained significant only for riboflavin after correcting for calorie-adjusted nutrient intake. Comparing Dietary Reference Intakes of participants pre- and postintervention, fewer patients met the Dietary Reference Intakes for thiamin and iron in the low FODMAP group, and for calcium and copper in the mNICE group. CONCLUSIONS: During a 4-week dietary intervention, the mean daily intake of most micronutrients remained stable and within the Recommended Dietary Allowances for both diets. Although decrease in several micronutrients was observed with implementation of the low-FODMAP diet relative to the mNICE diet, most of these disappeared after adjusting for energy intake.

Is Dyssynergic Defecation an Unrecognized Cause of Chronic Constipation in Patients Using Opioids?

OBJECTIVES: The impact of opioids on anorectal function is poorly understood but potentially relevant to the pathogenesis of opioid-induced constipation (OIC). To evaluate anorectal function testing (AFT) characteristics, symptom burden, and quality of life in chronically constipated patients prescribed an opioid (OIC) in comparison with constipated patients who are not on an opioid (NOIC). METHODS: Retrospective analysis of prospectively collected data on 3,452 (OIC = 588 and NOIC = 2,864) chronically constipated patients (Rome 3) who completed AFT. AFT variables included anal sphincter pressure and response during simulated defecation, balloon expulsion test (BET), and rectal sensation. Dyssynergic defecation (DD) was defined as an inability to relax the anal sphincter during simulated defecation and an abnormal BET. Patients completed Patient Assessment of Constipation Symptoms (PAC-SYM) and Patient Assessment of Constipation Quality of Life (PAC-QOL) questionnaires. RESULTS: The mean age of the study cohort was 49 years. Most patients were women (82%) and whites (83%). Patients with OIC were older than NOIC patients (50.7 vs 48.3, P = 0.001). OIC patients were significantly more likely to have DD (28.6% vs 21.4%, P < 0.001), an abnormal simulated defecation response on anorectal manometry (59% vs 43.8%, P < 0.001), and an abnormal BET (48% vs 42.5%, P = 0.02) than NOIC patients. OIC patients reported more severe constipation symptoms (P < 0.02) and worse quality of life (P < 0.05) than NOIC patients. DISCUSSION: Chronically constipated patients who use opioids are more likely to have DD and more severe constipation symptoms than NOIC.

Efficacy of Fecal Microbiota Transplantation in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis.

OBJECTIVES: Irritable bowel syndrome (IBS) is a common gastrointestinal condition with a heterogeneous pathophysiology. An altered gut microbiome has been identified in some IBS patients, and fecal microbiota transplantation (FMT) has been suggested to treat IBS. We performed meta-analyses and systematic review of available randomized controlled trials (RCTs) to evaluate the efficacy of FMT in IBS. METHODS: We performed a systematic literature search of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science. Selection criteria included RCTs of FMT vs placebo using FMT excipients or autologous FMT in IBS. Meta-analyses were conducted to evaluate the summary relative risk (RR) and 95% confidence intervals (CIs) of combined studies for primary outcome of improvement in global IBS symptoms as measured by accepted integrative symptom questionnaires or dichotomous responses to questions of overall symptom improvement. RESULTS: Among 742 citations identified, 7 were deemed to be potentially relevant, of which 4 studies involving 254 participants met eligibility. No significant difference in global improvement of IBS symptoms was observed at 12 weeks in FMT vs placebo (RR = 0.93; 95% CI 0.48-1.79). Heterogeneity among studies was significant (I = 79%). Subgroup analyses revealed benefits of single-dose FMT using colonoscopy and nasojejunal tubes in comparison with autologous FMT for placebo treatment (number needed to treat = 5, RR = 1.59; 95% CI 1.06-2.39; I = 0%) and a reduction in likelihood of improvement of multiple-dose capsule FMT RCTs (number needed to harm = 3, RR = 0.54; 95% CI 0.34-0.85; I = 13%). Placebo response was 33.7% in nonoral FMT RCTs and 67.8% in capsule FMT RCTs. The Grading of Recommendations Assessment, Development and Evaluation quality of the body of evidence was very low. DISCUSSION: Current evidence from RCTs does not suggest a benefit of FMT for global IBS symptoms. There remain questions regarding the efficacy of FMT in IBS as well as the lack of a clean explanation on the discrepant results among RCTs in subgroup analyses.

The role of diet in the management of irritable bowel syndrome: a focus on FODMAPs.

INTRODUCTION: Irritable bowel syndrome is a common condition that negatively impacts quality of life and results in significant health care expenditures. The vast majority of IBS patients associate their symptoms with eating. Numerous randomized, controlled trials suggest that restriction of dietary FODMAPs improves overall symptoms, abdominal pain, bloating and quality of life in more than half of IBS sufferers. There is emerging data which suggests that other diets (gluten free, guided elimination diets) might also be of benefit to IBS patients. Areas covered: Comprehensive literature review on dietary therapies available for IBS to date and exploration into individualized dietary therapy development based on diagnostic testing. Expert commentary: FODMAP elimination identifies IBS patients who are sensitive to FODMAPs. Responders should undergo a structured reintroduction of foods containing FODMAPs to determine a patient's sensitivities. This information can then be used to create a personalized, less restrictive low FODMAP diet. Future research should focus on the identification of other effective diet therapies focusing on supplementation of functional foods in addition to elimination and the development of biomarker-based diet treatment plans which identify the right treatment for the right patient.

Increased Prevalence of Rare Sucrase-isomaltase Pathogenic Variants in Irritable Bowel Syndrome Patients.

Patients with irritable bowel syndrome (IBS) often associate their symptoms to certain foods. In congenital sucrase-isomaltase deficiency (CSID), recessive mutations in the SI gene (coding for the disaccharidase digesting sucrose and 60% of dietary starch)1 cause clinical features of IBS through colonic accumulation of undigested carbohydrates, triggering bowel symptoms.2 Hence, in a previous study,3 we hypothesized that CSID variants reducing SI enzymatic activity may contribute to development of IBS symptoms. We detected association with increased risk of IBS for 4 rare loss-of-function variants typically found in (homozygous) CSID patients, because carriers (heterozygous) of these rare variants were more common in patients than in controls.1,4 Through a 2-step computational and experimental strategy, the present study aimed to determine whether other (dys-)functional SI variants are associated with risk of IBS in addition to known CSID mutations. We first aimed to identify all SI rare pathogenic variants (SI-RPVs) on the basis of integrated Mendelian Clinically Applicable Pathogenicity (M-CAP) and Combined Annotation Dependent Depletion (CADD) predictive (clinically relevant) scores; next, we inspected genotype data currently available for 2207 IBS patients from a large ongoing project to compare SI-RPV case frequencies with ethnically matched population frequencies from the Exome Aggregation Consortium (ExAC).

Nutrition in the management of gastrointestinal diseases and disorders: the evidence for the low FODMAP diet.

A growing interest from both physicians and patients is fueling research in the interaction of symptoms related to irritable bowel syndrome (IBS) and diet, particularly the low FODMAP diet. Recent studies further define the role of these short-chain fermentable carbohydrates on IBS symptoms and their effects in different parts of the gastrointestinal tract. Mounting evidence supports the use of a low FODMAP diet in the clinical setting, but this dietary approach is not without potential drawbacks. This review illustrates the mechanisms by which the low FODMAP diet leads to improvement in IBS symptoms, summarizes the available clinical evidence, and offers practical advice regarding implementation of this dietary strategy.