FODMAPs alter symptoms and the metabolome of patients with IBS: a randomised controlled trial

Fecal Clostridiales distribution and short-chain fatty acids reflect bowel habits in irritable bowel syndrome

Irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, is classified according to bowel habits as IBS with constipation (IBS-C), with diarrhea (IBS-D), with alternating constipation and diarrhea (IBS-M), and unsubtyped (IBS-U). The mechanisms leading to the different IBS forms are mostly unknown. This study aims to evaluate whether specific fecal bacterial taxa and/or short-chain fatty acids (SCFAs) can be used to distinguish IBS subtypes and are relevant for explaining the clinical differences between IBS subcategories. We characterized five fecal samples collected at 4-weeks intervals from 40 IBS patients by 16S rRNA gene profiling and SCFA quantification. Finally, we investigated the potential correlations in IBS subtypes between the fecal microbial signatures and host physiological and clinical parameters. We found significant differences in the distribution of Clostridiales OTUs among IBS subtypes and reduced levels of SCFAs in IBS-C compared to IBS-U and IBS-D patients. Correlation analyses showed that the diverse representation of Clostridiales OTUs between IBS subtypes was associated with altered levels of SCFAs; furthermore, the same OTUs and SCFAs were associated with the fecal cytokine levels and stool consistency. Our results suggest that intestinal Clostridiales and SCFAs might serve as potential mechanistic biomarkers of IBS subtypes and represent therapeutic targets.

Guidelines on the management of irritable bowel syndrome: In memory of Professor Witold Bartnik

These guidelines constitute an update of the previous "Recommendations on the management of irritable bowel syndrome" issued in 2008. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2008, the aetiology, epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of irritable bowel syndrome (IBS). The English-language acronym for the syndrome (IBS) has become popular in medical and popular scientific language. It is also widely recognized by patients who identify with this diagnosis. Therefore, in the discussed guidelines, this is what we will use.

Dietary Interventions to Modulate the Gut Microbiome-How Far Away Are We From Precision Medicine

The importance of the gut microbiome in human health and disease is fully acknowledged. A perturbation in the equilibrium among the different microbial populations living in the gut (dysbiosis) has been associated with the development of several types of diseases. Modulation of the gut microbiome through dietary intervention is an emerging therapeutic and preventive strategy for many conditions. Nevertheless, interpersonal differences in response to therapeutic treatments or dietary regimens are often observed during clinical trials, and recent research has suggested that subject-specific features of the gut microbiota may be responsible. In this review, we summarize recent findings in personalized nutrition, highlighting how individualized characterization of the microbiome may assist in designing ad hoc tailored dietary intervention for disease treatment and prevention. Moreover, we discuss the limitations and challenges encountered in integrating patient-specific microbial data into clinical practice.

Pre- and probiotic overview

The dynamic relationship between gut microbiota and its human host is also known as a trophic association that might range from commensalism, where only the microbe enjoys a positive effect from the relationship, to intestinal symbiosis where both host and microbe benefit from their interaction. In the last years, we have started to understand how alterations of the gut microbiota composition leading to the disruption of host-microbial interactions are associated and/or predispose individuals to disease conditions ranging from inflammatory bowel diseases to allergy and functional gastrointestinal disorders, such as irritable bowel syndrome. While we await important insights in this field, the microbiota is already a therapeutic target. Based on the actual definitions, prebiotics are defined as substrates that are selectively utilized by host microorganisms conferring a health benefit, while probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Although their health promoting activities encompasses numerous effects, including immunostimulation, competitive exclusion of pathogens, and gut barrier enhancement, the exact mechanism of action by which these compounds exert their beneficial actions in humans is only partially known. In this review, we highlight the current insights into the clinical applications of prebiotics and probiotics in gastroenterology.

A Systematic Review and Meta-Analysis Evaluating the Efficacy of a Gluten-Free Diet and a Low FODMAPs Diet in Treating Symptoms of Irritable Bowel Syndrome

OBJECTIVE

Dietary triggers such as gluten and highly fermentable oligo-, di- and monosaccharides and polyols (FODMAP)-containing foods have been associated with worsening irritable bowel syndrome (IBS) symptoms. However, the true impact of dietary restriction on IBS symptoms has remained unclear. The aim of this study was to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) examining the efficacy of exclusion diets (we focused on low FODMAP and gluten-free diets (GFD)) in IBS.

METHODS

We conducted a search of the literature using the electronic databases MEDLINE (1946 to November 2017), EMBASE (1974 to November 2017), Cochrane Central Register of Controlled Trials (November 2017), and Cochrane Database of Systematic Reviews (2005 to November, 2017) for RCTs of exclusion diets in IBS. Two independent reviewers screened citations and a third reviewer resolved disagreement. Two independent reviewers performed eligibility assessment and data abstraction. For inclusion, RCTs that evaluated an exclusion diet versus an alternative or usual diet and assessed improvement in either global IBS symptoms or abdominal pain were required. Data were synthesized as relative risk of symptoms remaining using a random effects model. Quality of evidence was assessed using GRADE methodology.

RESULTS

A total of 1726 citations were identified. After full-text screening a total of nine studies were eligible for the systematic review. There were two RCTs of a GFD, involving 111 participants. Both selected patients who responded to a GFD and then randomized them to continue the diet or have the diet "spiked" with gluten. A GFD was associated with reduced global symptoms compared with a control diet (RR = 0.42; 95% CI 0.11 to 1.55; I² = 88%), although this was not statistically significant. There were seven RCTs comparing a low FODMAP diet with various control interventions in 397 participants. A low FODMAP diet was associated with reduced global symptoms compared with control interventions (RR = 0.69; 95% CI 0.54 to 0.88; I² = 25%). The three RCTS that compared low FODMAP diet with rigorous control diets had the least heterogeneity between studies, but also the least magnitude of effect. The overall quality of the data was "very low" according to GRADE criteria.

CONCLUSIONS

There is insufficient evidence to recommend a GFD to reduce IBS symptoms. There is very low quality evidence that a low FODMAP diet is effective in reducing symptoms in IBS patients.

A Low FODMAP Gluten-Free Diet Improves Functional Gastrointestinal Disorders and Overall Mental Health of Celiac Disease Patients: A Randomized Controlled Trial

A subset of patients with celiac disease (CD) on a gluten-free diet (GFD) reported the persistence of functional gastrointestinal disorders. Foods containing fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) can trigger a broad range of gastrointestinal symptoms in sensitive individuals. We evaluated the effects of a low FODMAP diet (LFD) on gastrointestinal and psychological symptomatology in CD patients. A total of 50 celiac patients on GFDs and with persistence of gastrointestinal symptoms were included. The patients were randomly allocated to one of two dietary groups-one on a low FODMAP GFD (LF-GFD, n = 25) and the other on a regular GFD (R-GFD, n = 25)-for 21 days. Psychological symptomatology and quality of life were evaluated by the Symptom Checklist-90-R (SCL-90) and the Short Form (36) Health Survey (SF-36) questionnaires, respectively. Gastrointestinal symptomatology and general well-being were evaluated by visual analogue scale (VAS) scores. After 21 days, 21 and 23 patients completed the dietary treatment on LF-GFD and R-GFD, respectively. A reduced global SCL-90 index (p < 0.0003) was found in the LF-GFD group but not in the R-GFD one. However, the SF-36 scores did not differ between groups after treatment. The VAS for abdominal pain was much lower, and the VAS for fecal consistency enhanced after treatment in the LF-GFD group. General well-being increased in both groups but with a much higher improvement in the LF-GFD (p = 0.03). A short-term LFD regimen helps to improve the psychological health and gastrointestinal symptomatology with enhanced well-being of CD patients with persisting functional gastrointestinal symptomatology. The long-term clinical effects of LFD in particular subgroups of CD patients need further evaluation.

Pharmabiotic Manipulation of the Microbiota in Gastrointestinal Disorders: A Clinical Perspective

The advent and widespread availability of high-throughput technology has revolutionized the assessment of the communities of microorganisms that inhabit the gastrointestinal tract––the gut microbiota. As our understanding of the role of the microbiota in health and human disease increases, so also do efforts to prevent and treat disease through the modulation of the microbiota. Several strategies are available to us and range from time honored approaches, such as antibiotics and probiotics, to changes in diet, the administration of prebiotics as food supplements, and fecal microbiota transplantation. Of these, diet is perhaps the most pervasive but often ignored modulator of the microbiota, and a failure to recognize its impact complicates the interpretation of many microbiota studies. The impacts of antibiotics on the microbiota are more complex than originally thought and, though antibiotics can be life-saving, their effects on commensal bacterial populations can be clinically significant. Though there have been many studies of, and even more claims made for, probiotics, the majority of available studies suffer from significant deficits in study design and execution and many claims remain to be substantiated. Though holding much promise, the study of prebiotics in human disease is still in its infancy. Possibilities other than the administration of live organisms have been identified through efforts to mine the microbiota for novel therapeutics and include: dead organisms, bacterial components, small molecules elaborated by bacteria, and even bacterial DNA. Accordingly, the term pharmabiotic has been introduced to encompass the full range of therapeutic possibilities that the microbiota offers.

A low FODMAP diet is associated with changes in the microbiota and reduction in breath hydrogen but not colonic volume in healthy subjects

Background & aims

Ingestion of poorly digested, fermentable carbohydrates (fermentable oligo-, di-, mono-saccharides and polyols; FODMAPs) have been implicated in exacerbating intestinal symptoms and the reduction of intake with symptom alleviation. Restricting FODMAP intake is believed to relieve colonic distension by reducing colonic fermentation but this has not been previously directly assessed. We performed a randomised controlled trial comparing the effect of a low FODMAP diet combined with either maltodextrin or oligofructose on colonic contents, metabolites and microbiota.

Methods

A parallel randomised controlled trial in healthy adults (n = 37). All subjects followed a low FODMAP diet for a week and supplemented their diet with either maltodextrin (MD) or oligofructose (OF) 7g twice daily. Fasted assessments performed pre- and post-diet included MRI to assess colonic volume, breath testing for hydrogen and methane, and stool collection for microbiota analysis.

Results

The low FODMAP diet was associated with a reduction in Bifidobacterium and breath hydrogen, which was reversed by oligofructose supplementation. The difference in breath hydrogen between groups post-intervention was 27ppm (95% CI 7 to 50, P<0.01). Colonic volume increased significantly from baseline in both groups (OF increased 110ml (19.6%), 95% CI 30ml to 190ml, P = 0.01; MD increased 90ml (15.5%), 95% CI 6ml to 175ml, P = 0.04) with no significant difference between them. Colonic volumes correlated with total breath hydrogen + methane. A divergence in Clostridiales abundance was observed with increased abundance of Ruminococcaceae in the maltodextrin group, while in the oligofructose group, Lachnospiraceae decreased. Subjects in either group with high methane production also tended to have high microbial diversity, high colonic volume and greater abundance of methanogens.

Conclusion

A low FODMAP diet reduces total bacterial count and gas production with little effect on colonic volume.

The gut microbiome and irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders encountered in clinical practice. It is a heterogeneous disorder with a multifactorial pathogenesis. Recent studies have demonstrated that an imbalance in gut bacterial communities, or "dysbiosis", may be a contributor to the pathophysiology of IBS. There is evidence to suggest that gut dysbiosis may lead to activation of the gut immune system with downstream effects on a variety of other factors of potential relevance to the pathophysiology of IBS. This review will highlight the data addressing the emerging role of the gut microbiome in the pathogenesis of IBS and review the evidence for current and future microbiome based treatments.

Update on the Gastrointestinal Microbiome in Systemic Sclerosis

PURPOSE OF REVIEW

Accumulating evidence suggests that gut microbiota affect the development and function of the immune system and may play a role in the pathogenesis of autoimmune diseases. The purpose of this review is to summarize recent studies reporting gastrointestinal microbiota aberrations associated with the systemic sclerosis disease state.

RECENT FINDINGS

The studies described herein have identified common changes in gut microbial composition. Specifically, patients with SSc have decreased abundance of beneficial commensal genera (e.g., Faecalibacterium, Clostridium, and Bacteroides) and increased abundance of pathobiont genera (e.g., Fusobacterium, Prevotella, Erwinia). In addition, some studies have linked specific genera with the severity of gastrointestinal symptoms in systemic sclerosis. More research is needed to further characterize the gastrointestinal microbiota in systemic sclerosis and understand how microbiota perturbations can affect inflammation, fibrosis, and clinical outcomes. Interventional studies aimed at addressing/correcting these perturbations, either through dietary modification, pro/pre-biotic supplementation, or fecal transplantation, may lead to improved outcomes for patients with systemic sclerosis.

Role of the gut microbiota in nutrition and health

Ana M Valdes and colleagues discuss strategies for modulating the gut microbiota through diet and probiotics

Dietary Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs) and Gastrointestinal Disease

FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Dietary modification of FODMAPs has been shown to have significant effects on the physiology of the gastrointestinal tract and improves symptoms of abdominal pain, distention, and bloating in patients with irritable bowel syndrome. Structured withdrawal and reintroduction of FODMAPs supervised by a dietitian is the optimal practice for dietary FODMAP modification in irritable bowel syndrome. FODMAPs are present in enteral feeding formulas and may have a role in diarrhea and bloating in tube-fed patients. Emerging areas of research include the effects of dietary modification of FODMAPs on the microbiome, micronutrient absorption, and caloric intake. FODMAP dietary modification is an emerging area in other gastrointestinal disorders and is of relevance to all practicing dietitians.

Microbial Metabolism in the Mammalian Gut: Molecular Mechanisms and Clinical Implications

Human intestinal microbes participate actively at the interface of diet, nutrition, and overall health status. These biodiverse communities of microorganisms have a broader metabolic repertoire compared with their host, and they are able to synthesize and degrade substrates that would be otherwise unavailable. In recent years, we have recognized that healthy microbial communities are important for energy harvest and the regulation of body systems outside the digestive tract. Microbial dysbiosis, however, has been implicated in a number of human disorders, including obesity and inflammation. This dichotomy highlights the need to understand the factors that determine the composition and metabolic output of our resident and transient microbes. Throughout the human lifespan, we know that diet plays a major role in shaping gut microbial communities, as well as directing the types and amounts of metabolites produced. Understanding the factors that affect microbial metabolic output within the host may help identify the roles of microbes in health, as well as new targets for treatment in disease. In this article, we review facets of the assembly and activities of the healthy human intestinal microbiome, as well as ways that the microbiota has been shown to influence the host via metabolism of two dietary macronutrients: carbohydrates and amino acids.

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

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.

Does a low FODMAPs diet reduce symptoms of functional abdominal pain disorders? A systematic review in adult and paediatric population, on behalf of Italian Society of Pediatrics

BACKGROUND

Despite the rising of the Functional Gastrointestinal Disorders (FGIDs)' incidence in the last years, the etio-pathogenesis of FGIDs remains unclear. The diet seems to play an important role in these disorders. Indeed, at least two thirds of adult patients with Irritable Bowel Syndrome (IBS) and of children with FGIDs perceive their GI symptoms to be food-related. In particular, in the last years, more interest has been focused in the low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyol (FODMAPs) diet.

AIMS

To provide a systematic review on the efficacy of a low FODMAPs diet in reducing symptoms associated with functional abdominal pain disorders.

METHODS

Cochrane Library, MEDLINE (via Pubmed), and EMBASE databases from inception to June 2017 were searched. We included randomized controlled trials (RCTs), prospective and retrospective studies, systematic reviews and meta-analyses, reporting the efficacy of the FODMAPs diet intervention in FGIDs patients.

RESULTS

Nineteen studies were eligible. A FODMAPs-restricted diet is beneficial in 12/13 intervention trials. The low FODMAPs diet improves overall GI symptoms, especially abdominal pain and bloating. In children, only one study reported positive results of a low FODMAPs diet. No effect was found for the lactose free diet whilst fructose-restricted diet was effective in 3/4 studies. The duration of the intervention was very different among the studies, ranging from 2 days to 16 months, and from 3 and 9 weeks for the RCTs. The majority of the trials presented differences in symptoms scoring scales, diet, food diaries, and food frequencies questionnaire.

CONCLUSIONS

The FODMAPs-restricted diet may be an effective dietary intervention for reducing IBS symptoms in adults. In children, there are promising data, although only one randomized double-blind study exists and further data are needed to better clarify the role of FODMAPs and fructose-restricted diet in IBS. The current evidence does not support the use of a lactose-restricted diet in children with FGIDs.

Intestinal microbiome in scleroderma: recent progress

PURPOSE OF REVIEW

Our evolving understanding of how gut microbiota affects immune function and homeostasis has led many investigators to explore the potentially pathologic role of gut microbiota in autoimmune diseases. This review will discuss the rapidly advancing field of microbiome research in systemic sclerosis (SSc), an incurable autoimmune disease with significant gastrointestinal morbidity and mortality.

RECENT FINDINGS

Recent reports have identified common perturbations in gut microbiota across different SSc cohorts. Compared with healthy controls, patients with SSc have decreased abundance of beneficial commensal genera (e.g. Faecalibacterium, Clostridium and Bacteroides) and increased abundance of pathbiont genera (e.g. Fusobacterium, Prevotella and Erwinia). Certain genera may protect against (e.g. Bacteroides, Clostridium, and Lactobacillus), or conversely exacerbate (e.g. Fusobacterium and Prevotella) gastrointestinal symptoms in SSc. These genera represent potential targets to avert or treat gastrointestinal dysfunction in SSc.

SUMMARY

Emerging evidence suggests that alterations in gut microbiota exist in the SSc disease state; however, future basic and clinical studies are needed to ascertain the mechanism by which these alterations perpetuate inflammation and fibrosis in SSc. Therapeutic trials are also needed to investigate whether dietary interventions or fecal transplantation can restore the gut microbial balance and improve health outcomes in SSc. VIDEO ABSTRACT: http://links.lww.com/COR/A38.

Multivariate modelling of faecal bacterial profiles of patients with IBS predicts responsiveness to a diet low in FODMAPs

OBJECTIVE

The effects of dietary interventions on gut bacteria are ambiguous. Following a previous intervention study, we aimed to determine how differing diets impact gut bacteria and if bacterial profiles predict intervention response.

DESIGN

Sixty-seven patients with IBS were randomised to traditional IBS (n=34) or low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) (n=33) diets for 4 weeks. Food intake was recorded for 4 days during screening and intervention. Faecal samples and IBS Symptom Severity Score (IBS-SSS) reports were collected before (baseline) and after intervention. A faecal microbiota dysbiosis test (GA-map Dysbiosis Test) evaluated bacterial composition. Per protocol analysis was performed on 61 patients from whom microbiome data were available.

RESULTS

Responders (reduced IBS-SSS by ≥50) to low FODMAP, but not traditional, dietary intervention were discriminated from non-responders before and after intervention based on faecal bacterial profiles. Bacterial abundance tended to be higher in non-responders to a low FODMAP diet compared with responders before and after intervention. A low FODMAP intervention was associated with an increase in Dysbiosis Index (DI) scores in 42% of patients; while decreased DI scores were recorded in 33% of patients following a traditional IBS diet. Non-responders to a low FODMAP diet, but not a traditional IBS diet had higher DI scores than responders at baseline. Finally, while a traditional IBS diet was not associated with significant reduction of investigated bacteria, a low FODMAP diet was associated with reduced Bifidobacterium and Actinobacteria in patients, correlating with lactose consumption.

CONCLUSIONS

A low FODMAP, but not a traditional IBS diet may have significant impact on faecal bacteria. Responsiveness to a low FODMAP diet intervention may be predicted by faecal bacterial profiles.

TRIAL REGISTRATION NUMBER

NCT02107625.

Actinobacteria: A relevant minority for the maintenance of gut homeostasis

Actinobacteria are one the four major phyla of the gut microbiota and, although they represent only a small percentage, are pivotal in the maintenance of gut homeostasis. During the last decade many studies focused the attention on Actinobacteria, especially on their role both in gastrointestinal and systemic diseases and on their possible therapeutic use. In fact, classes of this phylum, especially Bifidobacteria, are widely used as probiotic demonstrating beneficial effects in many pathological conditions, even if larger in vivo studies are needed to confirm such encouraging results. This review aims to explore the current knowledge on their physiological functions and to speculate on their possible therapeutic role(s) in gastrointestinal and systemic diseases.

Fecal microbiota transplantation for managing irritable bowel syndrome

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11.2% of the world adult population. The intestinal microbiome is thought to play a pivotal role in the pathophysiology of IBS. The composition of the fecal microbiome in IBS patients differs from that in healthy individuals, but the exact bacteria species involved in the development of IBS remain to be determined. There is also an imbalance between useful and harmful bacteria (dysbiosis) in the intestinal microbiome in patients with IBS. Consuming prebiotics, probiotics, or synbiotics has a limited effect on IBS symptoms. In contrast, fecal microbiome transplantation (FMT) in IBS patients reverses the dysbiosis to normobiosis and reduces the IBS symptoms in about 70% of patients, and is not associated with any serious adverse events. Area covered: The available data on the microbiome and FMT in IBS regarding the efficacy of FMT in managing IBS were found using a PubMed search of these topics. Expert commentary: FMT is a promising tool for managing irritable syndrome. It appears to be effective, easy, and inexpensive procedure. However, more controlled studies involving larger cohorts of IBS are needed before FMT can be used as a routine procedure in the clinic.

Pediatric irritable bowel syndrome and other functional abdominal pain disorders: an update of non-pharmacological treatments

Functional abdominal pain disorders, including irritable bowel syndrome, are common in children and treatment can often be difficult. Pharmacological therapies and complementary treatments are widely used, despite the limited data in pediatrics. Areas covered: This review provides an overview of the available data for the use of diet, probiotics, percutaneous electrical nerve stimulation, and psychosocial interventions, including hypnotherapy, yoga, cognitive and behavioral therapy, and mind-body interventions for the treatment of functional abdominal pain disorders in children. The literature review included a PubMed search by each therapy, children, abdominal pain, and irritable bowel syndrome. Relevant articles to this review are discussed. Expert commentary: The decision on the use of pharmacological and complementary therapies should be based on clinical findings, evidence, availability, and in-depth discussion with the patient and family. The physician should provide education on the different interventions and their role on the treatment in an empathetic and warm manner providing ample time for the family to ask questions.

[Implementation of a low FODMAP diet for functional abdominal pain]

INTRODUCTION

The low FODMAP diet (fermentable oligosaccharides, monosaccharides, disaccharides, and polyols) has shown to be effective in adult patients with irritable bowel syndrome, but there are few studies on paediatric patients. The aim of this study is to assess the implementation and the outcomes of a low FODMAP diet in the treatment of functional abdominal pain in children from a Mediterranean area.

MATERIAL AND METHODS

A table was designed in which foods were classified according to their FODMAP content, as well as a 'Symptoms and Stools Diary'. A prospective study was conducted on children with functional abdominal pain in our Paediatric Gastroenterology Unit.

RESULTS

A total of 22 patients were enrolled in the trial, and 20 completed it. Data were collected of the abdominal pain features over a period of 3 days, and then patients followed a two-week low FODMAP diet. Afterwards, information about abdominal pain features was collected again. After the diet, they showed fewer daily abdominal pain episodes compared to baseline (1.16 [IQR: 0.41-3.33] versus 2 [IQR: 1.33-6.33] daily episodes, P=.024), less pain severity compared to baseline (1.41cm [IQR: 0.32-5.23] versus 4.63cm [IQR: 2.51-6.39] measured by 10-cm Visual Analogue Scale, P=.035), less interference with daily activities, and less gastrointestinal symptoms. Only 15% of patients found it difficult to follow the diet.

CONCLUSIONS

The implementation of a low FODMAP diet for 2 weeks in a Mediterranean paediatric population diagnosed with functional abdominal pain is possible with adapted diets. It was highly valued by patients, and they showed an improvement in abdominal pain symptoms assessed by objective methods.

Influence of low FODMAP and gluten-free diets on disease activity and intestinal microbiota in patients with non-celiac gluten sensitivity

BACKGROUND & AIMS

Non-celiac gluten sensitivity (NCGS) is characterized by intestinal and extra-intestinal symptoms triggered by ingestion of gluten. However, non-gluten triggers have recently been implicated, and a FODMAP (fermentable oligo-, di-, monosaccharides and polyols)-reduced diet can partially improve symptoms in NCGS. Our aim was to analyze the effect of a low FODMAP versus a gluten-free diet (GFD) on clinical symptoms, psychological well-being, intestinal inflammation and integrity, and stool microbiota.

METHODS

Nineteen patients with NCGS and ten healthy controls consumed a gluten-containing standard diet before starting a two-week low FODMAP diet; after a five day transition period, participants ingested a GFD for another two weeks. The primary outcome measure was the improvement of clinical symptoms in NCGS patients under the different diets. Secondary outcomes were the determination of dietary effects on intestinal inflammation, psychological well-being, and differences in stool microbiota between NCGS patients and controls.

RESULTS

The low FODMAP diet and especially the GFD led to a significant improvement of clinical and psychological symptoms in NCGS. A clear reduction in duodenal intraepithelial lymphocytes and mucin-producing Goblet cells was found after the GFD in these patients. Significant microbial differences between NCGS patients and controls were noticed in stool samples at every time point. Both diets caused microbial shifts in all participants, with a greater variability on genus level and metabolisms groups in NCGS patients.

CONCLUSIONS

Our findings suggest a multifactorial etiology of NCGS, due to a functional effect caused by FODMAPs, combined with a mild gluten-triggered immune reaction, and a microbiota dysbalance. CLINICALTRIAL.

GOV ID

NCT03268720.

The Role of Diet in the Treatment of Irritable Bowel Syndrome: A Systematic Review

Irritable bowel syndrome (IBS) is a multifaceted illness involving maladaptive shifts in the gut microbiota that affect the enteric nervous and immune systems, mucosal barrier function, the balance of neurotransmitters and hormones, and emotional well-being. There is abundant evidence indicating that certain foods elicit symptoms in IBS. Numerous elimination-type diets have been shown to alleviate symptoms. However, among these, the most controversial is a group of foods called fructo, oligo-, di-, and monosaccharides and polyols (FODMAPs). This paper reviews the role of diet and systematically analyze the literature for the role of FODMAPs in IBS.

Gut Microbiota-Based Therapies for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common, heterogeneous disorder characterized by abdominal pain associated with changes in bowel habits. The pathogenesis of IBS is multifactorial and may relate to alterations in the gut microbiota, changes in visceral sensation and motility, and genetic and environmental factors. Administration of systemic antibiotics may increase the risk of IBS by altering gastrointestinal homeostasis. Therapeutic interventions for IBS with diarrhea that are thought to target alterations in the gut microbiota include the nonsystemic antibiotic rifaximin, the medical food serum-derived bovine immunoglobulin, prebiotics, probiotics, and dietary modification. SYN-010 is a modified-release statin formulation that reduces methane production by Methanobrevibacter smithii and is currently in development for the treatment of patients with constipation-predominant IBS. Use of these interventions in the management of patients with IBS may function to restore a healthy gut microbiota and ameliorate symptoms of IBS.

Inaccuracy of patient-reported descriptions of and satisfaction with bowel actions in irritable bowel syndrome

BACKGROUND

Perception of diarrhea and constipation differs greatly. This study aimed to correlate subjective and objective assessment of fecal characteristics in irritable bowel syndrome (IBS) patients.

METHODS

Data from two interventional dietary trials with varying FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) or gluten content were interrogated. Subjects rated their dissatisfaction with stool consistency daily using a visual analog scale during the interventions. Subjects collected stools at the end of each intervention. Each stool was scored according to the King's Stool Chart (KSC). Fecal water content (FWC) was measured on pooled feces by freeze drying, with diarrhea defined as ≥78%.

KEY RESULTS

Seventy IBS (Rome III) and eight healthy subjects were studied. Each subject's self-rating of stool consistency during the most symptomatic diet was approximately double that of their least. Degree of dissatisfaction with stool consistency correlated poorly with changes in FWC and KSC. IBS subtype related poorly to objective measures of stool consistency. Sixty percent of IBS-D subjects had diarrhea on objective measures. Eighty-five percent with IBS-C had hard and formed stools but three patients met the criteria for diarrhea. One healthy subject had diarrhea on FWC and KSC, and six had hard, formed stools. No differences in FWC was observed when subjects consumed differing amounts of FODMAPs or gluten (all P > .200).

CONCLUSIONS AND INFERENCES

There are major disparities between patients' stool descriptions and objective features of constipation and diarrhea. Patient-reported bowel habits require more interrogation for accurate IBS subtyping. Varying FODMAP or gluten content of the diet is not associated with consistent change in FWC.

Fructans Exacerbate Symptoms in a Subset of Children With Irritable Bowel Syndrome

BACKGROUND & AIMS

Dietary fructans exacerbate symptoms in some, but not all, adults with irritable bowel syndrome (IBS). We sought to determine whether fructans worsen symptoms in children with IBS and whether clinical and psychosocial factors, and/or gas production, can identify those who are fructan sensitive.

METHODS

We performed a double-blind placebo-controlled (maltodextrin) cross-over trial of 23 children with IBS, based on pediatric Rome III criteria, from September 2014 through December 2016. At baseline, participants completed 1-week pain and stool diaries and a 3-day food record and psychosocial factors (depression, anxiety, and somatization) were measured. Subjects were randomly assigned to groups that were provided meals for 72 hours containing either fructans or maltodextrin (0.5 g/kg; maximum, 19 g). Following a washout period of 10 days or more, the subjects received the meal they were not given during the first study period (crossed over). Gastrointestinal symptoms and breath hydrogen and methane production were captured during each meal period. Fructan sensitivity was defined as an increase of 30% or more in abdominal pain frequency following fructan ingestion.

RESULTS

Subjects had more mean episodes of abdominal pain/day during the fructan-containing diet (3.4 ± 2.6) vs the maltodextrin-containing diet (2.4 ± 1.7) (P < .01), along with more severe bloating (P < .05) and flatulence (P = .01). Hydrogen (but not methane) production was greater while subjects were on the fructan-containing diet (617 ± 305 ppm∗h) than the maltodextrin-containing diet (136 ± 78 ppm*h) (P < .001). Eighteen subjects (78.2%) had more frequent abdominal pain while on the fructan-containing diet and 12 (52.2%) qualified as fructan sensitive. We found no difference between fructan-sensitive and fructan-insensitive subjects in baseline abdominal pain or bowel movement characteristics, dietary intake, psychosocial parameters, IBS subtype, or gas production.

CONCLUSIONS

In a randomized controlled trial of children with IBS, we found fructans to exacerbate several symptoms. However, fructan sensitivity cannot be identified based on baseline gastrointestinal symptoms, dietary intake, psychosocial factors, or gas production. Clinicaltrials.gov no: NCT02842281.

Dietary therapies for functional bowel symptoms: Recent advances, challenges, and future directions

BACKGROUND

Functional gastrointestinal symptoms in irritable bowel syndrome (IBS) and quiescent inflammatory bowel disease (IBD) cause significant morbidity and a reduction in quality of life. Multiple dietary therapies are now available to treat these symptoms, but supporting evidence for many is limited. In addition to a further need for studies demonstrating efficacy and mechanism of action of dietary therapies, the risk of nutritional inadequacy, alterations to the microbiome and changes in quality of life are key concerns requiring elucidation. Identifying predictors of response to dietary therapy is an important goal as management could be tailored to the individual to target specific dietary components, and thereby reduce the level of dietary restriction necessary.

PURPOSE

This review discusses the available dietary therapies to treat symptoms in patients with IBS and patients with quiescent IBD suffering from IBS symptoms, with the aim to understand where current dietary evidence lies and how to move forward in dietary research in this field.

Fructo-oligosaccharide intensifies visceral hypersensitivity and intestinal inflammation in a stress-induced irritable bowel syndrome mouse model

AIM

To determine whether fructo-oligosaccharide (FOS) affects visceral sensitivity, inflammation, and production of intestinal short-chain fatty acids (SCFA) in an irritable bowel syndrome (IBS) mouse model.

METHODS

Mice were randomly assigned to daily oral gavage of saline solution with or without FOS (8 g/kg body weight) for 14 d. Mice were further assigned to receive either daily one-hour water avoidance stress (WAS) or sham-WAS for the first 10 d. After 2 wk, visceral sensitivity was measured by abdominal withdrawal reflex in response to colorectal distension and mucosal inflammation was evaluated. Gas chromatography, real-time reverse transcription PCR, and immunohistochemistry assays were used to quantify cecal concentrations of SCFA, intestinal cytokine expression, and number of intestinal mast cells per high-power field (HPF), respectively.

RESULTS

Mice subjected to WAS exhibited visceral hypersensitivity and low-grade inflammation. Among mice subjected to WAS, FOS increased visceral hypersensitivity and led to higher cecal concentrations of acetic acid (2.49 ± 0.63 mmol/L vs 1.49 ± 0.72 mmol/L, P < 0.05), propionic acid (0.48 ± 0.09 mmol/L vs 0.36 ± 0.05 mmol/L, P < 0.01), butyric acid (0.28 ± 0.09 mmol/L vs 0.19 ± 0.003 mmol/L, P < 0.05), as well as total SCFA (3.62 ± 0.87 mmol/L vs 2.27 ± 0.75 mmol/L, P < 0.01) compared to saline administration. FOS also increased ileal interleukin (IL)-23 mRNA (4.71 ± 4.16 vs 1.00 ± 0.99, P < 0.05) and colonic IL-1β mRNA (2.15 ± 1.68 vs 0.88 ± 0.53, P < 0.05) expressions as well as increased mean mast cell counts in the ileum (12.3 ± 2.6 per HPF vs 8.3 ± 3.6 per HPF, P < 0.05) and colon (6.3 ± 3.2 per HPF vs 3.4 ± 1.2 per HPF, P < 0.05) compared to saline administration in mice subjected to WAS. No difference in visceral sensitivity, intestinal inflammation, or cecal SCFA levels was detected with or without FOS administration in mice subjected to sham-WAS.

CONCLUSION

FOS administration intensifies visceral hypersensitivity and gut inflammation in stress-induced IBS mice, but not in the control mice, and is also associated with increased intestinal SCFA production.

Existing and emerging therapies for managing constipation and diarrhea

Functional bowel disorders (i.e., constipation and diarrhea) are characterized by abdominal pain, bloating, distention, and/or bowel habit abnormalities in the absence of obvious anatomic or physiologic abnormalities on routine diagnostic tests. These symptoms are attributable to gastrointestinal sensorimotor dysfunctions resulting from peripheral and/or central mechanisms. Available drugs target the underlying bowel disturbance (i.e., constipation, diarrhea, or both), supplemented when necessary by management of pain. Osmotic and stimulant laxatives, secretagogues, and serotonin 5-HT4 receptor agonists are approved for treating constipation. Loperamide, anticholinergic agents, rifaximin, bile-acid binding agents, eluxadoline, and clonidine are used to treat diarrhea. Several exciting new compounds, some of which have been evaluated in humans, are currently under development.

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.

Irritable bowel syndrome and diet: where are we in 2018?

PURPOSE OF REVIEW

The aim is to review the most recent advances in the evidence supporting the use of various dietary interventions for the management of irritable bowel syndrome (IBS).

RECENT FINDINGS

There is insufficient evidence of the effect of fibres other than psyllium in IBS, whereas the recent studies on prebiotics suggest a limited effect in IBS. Recent probiotic trials continue to provide varying results, with some probiotic strains exhibiting beneficial effects, whereas others show no effect. Recent trials have also confirmed the clinical effectiveness of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (i.e. low FODMAP diet) in IBS. Although gluten sensitivity has also been recently investigated, its presence cannot be confirmed yet because of the presence of other potential contributing compounds in wheat. Studies also suggest a potential beneficial effect of peppermint oil, which warrants further research.

SUMMARY

It is clear that a low FODMAP diet has a beneficial effect in a majority of patients with IBS. Probiotics also have great potential in the management of IBS; however, it is still unclear which strains and doses are the most beneficial. Further research is needed on the effect of different fibres, or combinations of fibres, in IBS.

The role of fermentable carbohydrates and beverages in the symptomatology of functional gastrointestinal disease

OBJECTIVES

The pathophysiology behind functional gastrointestinal disease (FGID) has not been defined, but an intestinal accumulation of fermentable short-chain carbohydrates (FODMAPs) is thought to be involved. A restricted coffee intake is recommended. The aim was to investigate if symptoms of FGID were associated with intake of certain foods (including FODMAPs), as well as beverages (including coffee and tea).

METHOD AND MATERIALS

Data were used from participants, age range 45-75 years, who had answered the EpiHealth questionnaire about their background factors, health status and intake of food and beverages. After exclusion of organic bowel diseases, 16,840 participants remained. The impact of food and beverages on functional abdominal pain, functional bloating, functional constipation and functional diarrhea were examined by adjusted binary logistic regression.

RESULTS

Wholemeal bread (Swedish cracker) (OR: 1.361; 95% CI: 1.001-1.851) and white bread (low fiber content) (OR: 1.527; 95% CI: 1.075-2.169) were associated with constipation, whereas soft wholemeal bread (high fiber content) was associated with diarrhea (OR: 1.601; 95% CI: 1.040-2.463). Cheese was associated with bloating (OR: 1.460; 95% CI: 1.004-2.123). A high tea intake was associated with abdominal pain (p for trend =.003), bloating (p for trend = .039) and diarrhea (p for trend <.001), whereas coffee intake was associated with a decreased risk of abdominal pain (p for trend = .002) and bloating (p for trend = .007). High soda intake associated with abdominal pain and bloating and juice with diarrhea.

CONCLUSION

There are weak associations between intake of grain and dairy products and FGID symptoms. Tea is associated with increased risks, whereas coffee is associated with lower risks, of FGID symptoms.

Microbiota-Brain-Gut Axis and Neurodegenerative Diseases

PURPOSE OF REVIEW

The purposes of this review were as follows: first, to provide an overview of the gut microbiota and its interactions with the gut and the central nervous system (the microbiota-gut-brain axis) in health, second, to review the relevance of this axis to the pathogenesis of neurodegenerative diseases, such as Parkinson's disease, and, finally, to assess the potential for microbiota-targeted therapies.

RECENT FINDINGS

Work on animal models has established the microbiota-gut-brain axis as a real phenomenon; to date, the evidence for its operation in man has been limited and has been confronted by considerable logistical challenges. Animal and translational models have incriminated a disturbed gut microbiota in a number of CNS disorders, including Parkinson's disease; data from human studies is scanty. While a theoretical basis can be developed for the use of microbiota-directed therapies in neurodegenerative disorders, support is yet to come from high-quality clinical trials. In theory, a role for the microbiota-gut-brain axis is highly plausible; clinical confirmation is awaited.

A Diet Low in FODMAPs Reduces Symptoms in Patients With Irritable Bowel Syndrome and A Probiotic Restores Bifidobacterium Species: A Randomized Controlled Trial

BACKGROUND & AIMS

Dietary restriction of fermentable carbohydrates (a low FODMAP diet) has been reported to reduce symptoms in some patients with irritable bowel syndrome (IBS). We performed a randomized, placebo-controlled study to determine its effects on symptoms and the fecal microbiota in patients with IBS.

METHODS

We performed a 2×2 factorial trial of 104 patients with IBS (18-65 years old), based on the Rome III criteria, at 2 hospitals in the United Kingdom. Patients were randomly assigned (blinded) to groups given counselling to follow a sham diet or diet low in FODMAPs for 4 weeks, along with a placebo or multistrain probiotic formulation, resulting in 4 groups (27 receiving sham diet/placebo, 26 receiving sham diet/probiotic, 24 receiving low FODMAP diet /placebo, and 27 receiving low FODMAP diet/probiotic). The sham diet restricted a similar number of staple and non-staple foods as the low FODMAP diet; the diets had similar degrees of difficulty to follow. Dietary counselling was given to patients in all groups and data on foods eaten and compliance were collected. The incidence and severity of 15 gastrointestinal symptoms and overall symptoms were measured daily for 7 days before the study period; along with stool frequency and consistency. At baseline, global and individual symptoms were measured, along with generic and disease-specific health-related quality of life, using standard scoring systems. All data were collected again at 4 weeks, and patients answered questions about adequate symptom relief. Fecal samples were collected at baseline and after 4 weeks and analyzed by quantitative PCR and 16S rRNA sequencing. The co-primary endpoints were adequate relief of symptoms and stool Bifidobacterium species abundance at 4 weeks.

RESULTS

There was no significant interaction between the interventions in adequate relief of symptoms (P = .52) or Bifidobacterium species (P = .68). In the intention-to-treat analysis, a higher proportion of patients in the low FODMAP diet had adequate symptom relief (57%) than in the sham diet group (38%), although the difference was not statistically significant (P = .051). In the per-protocol analysis, a significantly higher proportion of patients on the low FODMAP diet had adequate symptom relief (61%) than in the sham diet group (39%) (P = .042). Total mean IBS-Severity Scoring System score was significantly lower for patients on the low FODMAP diet (173 ± 95) than the sham diet (224 ± 89) (P = .001), but not different between those given probiotic (207 ± 98) or placebo (192 ± 93) (P = .721) Abundance of Bifidobacterium species was lower in fecal samples from patients on the low FODMAP diet (8.8 rRNA genes/g) than patients on the sham diet (9.2 rRNA genes/g) (P = .008), but higher in patients given probiotic (9.1 rRNA genes/g) than patients given placebo (8.8 rRNA genes/g) (P = .019). There was no effect of the low FODMAP diet on microbiota diversity in fecal samples.

CONCLUSIONS

In a placebo-controlled study of patients with IBS, a low FODMAP diet associates with adequate symptom relief and significantly reduced symptom scores compared with placebo. It is not clear whether changes resulted from collective FODMAP restriction or removal of a single component, such as lactose. Co-administration of the multistrain probiotic increased numbers of Bifidobacterium species, compared with placebo, and might be given to restore these bacteria to patients on a low FODMAP diet. Trial registration no: ISRCTN02275221.

The microbiome and disorders of the central nervous system

Alterations of the gut microbiota have been associated with stress-related disorders including depression and anxiety and irritable bowel syndrome (IBS). More recently, researchers have started investigating the implication of perturbation of the microbiota composition in neurodevelopmental disorders including autism spectrum disorders and Attention-Deficit Hypersensitivity Disorder (ADHD). In this review we will discuss how the microbiota is established and its functions in maintaining health. We also summarize both pre and post-natal factors that shape the developing neonatal microbiota and how they may impact on health outcomes with relevance to disorders of the central nervous system. Finally, we discuss potential therapeutic approaches based on the manipulation of the gut bacterial composition.

Low-FODMAP Diet Improves Irritable Bowel Syndrome Symptoms: A Meta-Analysis

Irritable bowel syndrome (IBS) affects 7–15% of the general population. A recently devised dietary approach consists of restricting foods with highly fermentable oligo-, di-, and monosaccharides, and polyols (FODMAPs), which can trigger and/or exacerbate IBS symptoms. The aim of this study is to use meta-analysis to provide an update on the randomised control trials (RCTs) and cohort studies, and examine them separately in relation to diet type. Papers were selected using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart. Cohen’s d and odds ratios were used as a measure of effect size for RCTs. A random effects model was used to account for different sources of variation among studies. Heterogeneity was assessed using Q statistics, I², Tau, and Tau². Publication bias was analysed and represented by a funnel plot, and funnel plot symmetry was assessed with Egger’s test. The results showed that in the RCTs, the patients receiving a low-FODMAP diet experienced a statistically significant pain and bloating reduction compared with those receiving a traditional diet; as regards to stool consistency, there was no significant difference between treatments. A significant reduction in abdominal pain and bloating were described by patients receiving a low-FODMAP diet compared with those receiving a high-FODMAP diet. In cohort studies, pain and bloating were significantly reduced after treatment compared with the baseline diet. We conclude that there is evidence that a low-FODMAP diet could have a favourable impact on IBS symptoms, especially abdominal pain and bloating. However, it remains to be demonstrated whether a low-FODMAP diet is superior to conventional IBS diets, especially in the long term.

Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies

BACKGROUND

Irritable bowel syndrome (IBS) and functional digestive tract disorders, e.g. functional bloating, carbohydrate maldigestion and intolerances, are very common disorders frequently causing significant symptoms that challenge health care systems. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet is one of the possible therapeutic approaches for decreasing abdominal symptoms and improving quality of life.

OBJECTIVES

We aimed to meta-analyze data on the therapeutic effect of a low-FODMAP diet on symptoms of IBS and quality of life and compare its effectiveness to a regular, standard IBS diet with high FODMAP content, using a common scoring system, the IBS Symptom Severity Score (IBS-SSS).

METHODS

A systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library as well as in the references in a recent meta-analysis. Adult patients diagnosed with IBS according to the Rome II, Rome III, Rome IV or NICE criteria were included in the analysis.

STATISTICAL METHODS

Mean differences with 95% confidence intervals were calculated from studies that contained means, standard deviation (SD) or mean differences and SD of differences and p-values. A random effect model was used because of the heterogeneity (Q test (χ2) and I2 indicator). A p-value of less than 0.05 was chosen to indicate a significant difference.

RESULTS

The literature search yielded 902 publications, but only 10 were eligible for our meta-analysis. Both regular and low-FODMAP diets proved to be effective in IBS, but post-diet IBS-SSS values were significantly lower (p = 0.002) in the low-FODMAP group. The low-FODMAP diet showed a correlation with the improvement of general symptoms (by IBS-SSS) in patients with IBS.

CONCLUSIONS

This meta-analysis provides high-grade evidence of an improved general symptom score among patients with irritable bowel syndrome who have maintained a low-FODMAP diet compared to those on a traditional IBS diet, therefore showing its superiority to regular IBS dietary therapy. These data suggest that a low-FODMAP diet with dietitian control can be a candidate for first-line therapeutic modality in IBS. Because of a lack of data, well-planned randomized controlled studies are needed to ascertain the correlation between improvement of separate key IBS symptoms and the effect of a low-FODMAP diet.

Bifidobacterium-Rich Fecal Donor May Be a Positive Predictor for Successful Fecal Microbiota Transplantation in Patients with Irritable Bowel Syndrome

BACKGROUND/AIMS

Dysbiosis is associated with various systemic disorders including irritable bowel syndrome (IBS). Fecal microbiota transplantation (FMT) might restore intestinal microbial balance. The study aimed to determine the safety and efficacy of FMT in IBS patients, as well as also positive predictors for FMT.

METHODS

This was a single-arm, open-label study. Eligible patients were diagnosed based on Rome III Diagnostic Criteria. Fecal materials were administered to the patient via colonoscopy. The primary end point was a change in the Bristol stool form scale at 4 weeks after FMT. Recovery to types 3-4 was considered a clinical response. The secondary end point was a change in intestinal microbiota and psychological status using the Hamilton Rating Scale.

RESULTS

Ten patients were enrolled. Six patients achieved a clinical response. The diversity of patients 4 weeks after FMT increased significantly compared with patients before FMT, and that of responding patients was significantly higher than non-responder patients. The abundance of Bifidobacterium in effective donors was significantly higher than in ineffective donors and patients. Psychological status of all patients was significantly improved after FMT.

CONCLUSIONS

FMT for patients with IBS is safe, and relatively effective. Bifidobacterium-rich fecal donor may be a positive predictor for successful FMT. Key Summary: (1) Dysbiosis is associated with various gastrointestinal disorders including IBS. (2) FMT has potential to restore intestinal microbial balance. (3) We showed that FMT improved stool form and psychological status of IBS patients. (4) Bifidobacterium-rich donor efficiently induced symbiosis in IBS patients.

Targeting Histamine Receptors in Irritable Bowel Syndrome: A Critical Appraisal

Irritable bowel syndrome is a group of functional gastrointestinal disorders with not yet fully clarified etiology. Recent evidence suggesting that mast cells may play a central role in the pathogenesis of irritable bowel syndrome paves the way for agents targeting histamine receptors as a potential therapeutic option in clinical treatment. In this review, the role of histamine and histamine receptors is debated. Moreover, the clinical evidence of anti-histamine therapeutics in irritable bowel syndrome is discussed.

Low fermentable, oligo-, di-, mono-saccharides and polyol diet in the treatment of irritable bowel syndrome: A systematic review and meta-analysis

OBJECTIVES

The aim of this review was to systematically assess and meta-analyze the effects of a low fermentable, oligo-, di-, mono-saccharides and polyol (FODMAP) diet (LFD) on the severity of symptoms, quality of life, and safety in patients with irritable bowel syndrome (IBS).

METHODS

The MEDLINE/PubMed, Scopus, and Cochrane Library databases were screened through January 19, 2016. Randomized controlled trials (RCTs) that compared LFD to other diets were included if they assessed symptoms of IBS or abdominal pain in patients with IBS. Safety, quality of life, anxiety, depression, and effect on gut microbiota were defined as secondary outcomes. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated.

RESULTS

Nine RCTs with a total of 596 subjects were included. Three RCTs compared LFD with a habitual diet, two RCTs provided all meals and compared LFD with a western diet, one RCT each compared LFD with a diet high in FODMAPs or a sham diet, and two RCTs compared with other diet recommendations for IBS. A meta-analysis revealed significant group differences for LFD compared with other diets with regard to gastrointestinal symptoms (SMD = -0.62; 95% CI = -0.93 to -0.31; P = 0.0001), abdominal pain (SMD = -0.50; 95% CI = -0.77 to -0.22; P = 0.008), and health-related quality of life (SMD = 0.36; 95% CI = 0.10-0.62; P = 0.007). Three studies reported a significant reduction in luminal bifidobacteria after LFD. Adverse events were assessed in three RCTs only and no intervention-related adverse events were reported.

CONCLUSIONS

This meta-analysis found evidence of the short-term efficacy and safety of LFD in patients with IBS. However, only a preliminary recommendation for LFD can be made until long-term effects are investigated.

Long-term irritable bowel syndrome symptom control with reintroduction of selected FODMAPs

AIM

To investigate the long-term effect of dietary education on a low fermentable oligosaccharide, disaccharide and polyol (FODMAP) diet on irritable bowel syndrome (IBS) symptoms and quality of life (QoL).

METHODS

Participants with IBS (Rome III) were randomized to two groups. Group I commenced a low FODMAP diet at baseline. At three months, group II, so far a comparator group, crossed over to a low FODMAP diet while group I started re-challenging foods. All patients completed the IBS SSS (IBS symptom severity scoring system, 0-500 points increasing with severity), IBS QoL questionnaire (0-100 increasing with QoL), a FODMAP specific food frequency questionnaire and provided a stool sample at baseline, three and six months for microbiome analysis.

RESULTS

Fifty participants were enrolled into group I (n = 23) or group II (n = 27). Participants in both groups were similar in baseline values but with more men in group I. There was a significantly lower IBS SSS (275.6 ± 63.6 to 128.8 ± 82.5 vs 246.8 ± 71.1 to 203.6 ± 70.1) (P < 0.0002) and increased QoL (68.5 ± 18.0 to 83 ± 13.4 vs 72.9 ± 12.8 to 73.3 ± 14.4) (P < 0.0001) in group I vs group II at 3 mo. The reduced IBS SSS was sustained at 6 mo in group I (160 ± 102) and replicated in group II (124 ± 76). Fiber intake decreased on the low FODMAP diet (33 ± 17 g/d to 21 ± 8 g/d) (P < 0.01) and after re-introducing FODMAP containing foods increased again to 27 ± 9 g/d. There was no change seen in the intestinal microbiome when participants adopted a low FODMAP diet.

CONCLUSION

This study demonstrated that a reduction in FODMAPs improves symptoms in IBS and this improvement can be maintained while reintroducing FODMAPs.

A Systematic Review of the Effects of Polyols on Gastrointestinal Health and Irritable Bowel Syndrome

Polyols are sugar alcohols found in certain fruits, vegetables, and sugar-free sweeteners. They make up a component of the diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which is gaining popularity in the treatment of patients with irritable bowel syndrome (IBS). We conducted a systematic review to evaluate the effects of polyols on the gastrointestinal tract in healthy men and women and in patients with IBS. Utilizing PubMed, Ovid, and Embase databases, we conducted a search on individual polyols and each of these terms: fermentation, absorption, motility, permeability, and gastrointestinal symptoms. Standard protocols for a systematic review were followed. We found a total of 1823 eligible articles, 79 of which were included in the review. Overall, available work has shown that polyol malabsorption generally occurs in a dose-dependent fashion in healthy individuals, and malabsorption increases when polyols are ingested in combination. However, studies in patients with IBS have shown conflicting results pertaining to polyol malabsorption. Polyol ingestion can lead to intestinal dysmotility in patients with IBS. Regarding the microbiome, moderate doses of polyols have been shown to shift the microbiome toward an increase in bifidobacteria in healthy individuals and may therefore be beneficial as prebiotics. However, data are limited regarding polyols and the microbiome in patients with IBS. Polyols can induce dose-dependent symptoms of flatulence, abdominal discomfort, and laxative effects when consumed by both healthy volunteers and patients with IBS. Further research is needed to better understand the effects of specific polyols on gastrointestinal function, sensation, and the microbiome in health and gastrointestinal disorders such as IBS.

Systematic review: quality of trials on the symptomatic effects of the low FODMAP diet for irritable bowel syndrome

BACKGROUND

The low Fermentable Oligo-, Di- Monosaccharides, and Polyoles (FODMAP) diet is a new treatment option for irritable bowel syndrome (IBS). Experts refer to the diet as supported by high level of evidence, but an evaluation of the quality of trials is lacking.

AIM

To provide a systematic review of the quality of trials on the symptomatic effects of the low FODMAP diet for IBS.

METHODS

Pubmed and EMBASE were searched for randomised controlled trials (RCTs) reporting effect of the low FODMAP diet on IBS symptoms. The quality of trials was evaluated by estimating risk of bias and assessing trial methodology.

RESULTS

Nine RCTs were eligible, including 542 patients. The intervention period was from 2 days to 6 weeks and one trial included a 6-month follow-up. Three trials intervened by providing meals, controlling with a diet high in FODMAP content. In six trials, the intervention was instruction by a dietician and a variety of control interventions were used, all with limited established efficacy. Domains with a high risk of bias were identified for all the trials. High risk of bias dominated domains regarding blinding, with only one trial double-blinded.

CONCLUSIONS

The RCTs on the low FODMAP diet are characterized by high risk of bias. The diet has not been studied in a randomised, controlled setting for more than 6 weeks and trials examining the effect of the important reintroduction period are lacking. There is a risk that the symptomatic effects reported in the trials are driven primarily by a placebo response.

Neuroimmune factors in functional gastrointestinal disorders: A focus on irritable bowel syndrome

BACKGROUND

Abnormal abdominal pain perception is the most bothersome and difficult to treat symptom of functional gastrointestinal disorders (FGIDs). Visceral pain stimuli are perceived and transmitted by afferent neurons residing in the dorsal root ganglia that have sensory nerve endings in the gut wall and mesentery. Accumulating evidence indicates that peripheral activation and sensitization of these sensory nerve endings by bioactive mediators released by activated immune cells, in particular mast cells, can lead to aberrant neuroimmune interactions and the development and maintenance of visceral hypersensitivity. Besides direct neuronal activation, low concentrations of proteases, histamine, and serotonin can chronically sensitize nociceptors, such as TRP channels, leading to persistent aberrant pain perception.

PURPOSE

This review discusses the potential mechanisms underlying aberrant neuroimmune interactions in peripheral sensitization of sensory nerves. A better understanding of the cells, mediators, and molecular mechanisms triggering persistent aberrant neuroimmune interactions brings new insights into their contribution to the physiology and pathophysiology of visceral pain perception and provides novel opportunities for more efficient therapeutic treatments for these disorders.