History of the low FODMAP diet

An evidence-based update on the diagnosis and management of irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction affecting 5% of the population. The cardinal symptoms are abdominal pain and altered stool form or frequency.

AREAS COVERED

Diagnosis and management of IBS. We searched the literature for diagnostic accuracy studies, randomized controlled trials, and meta-analyses. A positive diagnosis of IBS, alongside testing to exclude celiac disease, is recommended. Exhaustive investigation has a low yield. Patients should be offered traditional dietary advice. If response is incomplete, specialist dietetic guidance should be considered. Probiotics may be beneficial, but quality of evidence is poor. First-line treatment of constipation is with laxatives, with secretagogues used where these are ineffective. Anti-diarrheal drugs should be used first-line for diarrhea, with second-line drugs including 5-hydroxytryptamine-3 antagonists, eluxadoline, or rifaximin, where available. First-line treatment of abdominal pain should be with antispasmodics, with gut-brain neuromodulators prescribed second-line. Low-dose tricyclic antidepressants, such as amitriptyline, are preferred. Brain-gut behavioral therapies are effective and have evidence for efficacy in patients refractory to standard therapies.

EXPERT OPINION

Despite substantial advances, there remains scope for improvement in terms of both the diagnosis and management of IBS. Reinforcement of positive diagnostic strategies for the condition and novel treatment paradigms are required.

Use of Carbohydrate (CHO), Gluten-Free, and FODMAP-Free Diets to Prevent Gastrointestinal Symptoms in Endurance Athletes: A Systematic Review

BACKGROUND

Gastrointestinal symptoms (GISs) can affect the performance of endurance athletes (EAs). This study aims to analyze the efficacy of carbohydrate (CHO), gluten-free, and low-mono-saccharide and polyol (FODMAP) diets in preventing GISs in adult EAs of both sexes.

METHODS

A systematic search was conducted prior to 30 June 2024 in accordance with the PRISMA statement. We searched for original studies from the last eight years, in English or Spanish, that looked at the effect of CHO, gluten-free, or FODMAP diets on the GISs of EAs. In PubMed, the MeSH (medical subject heading) categories were used. The search was repeated in EBSCO, Google Scholar, and Web of Science. The inclusion criteria were determined using the PICOS framework and the risk of bias in each paper was assessed using the PEDro scale quality criteria checklist (systematic review registration: INPLASY202490080).

RESULTS

Of 289 articles identified, only 3.5% met the eligibility criteria. All studies found that GISs are common in EAs. We found that 60% of the articles used an experimental method; moreover, based on 80% of the articles, following a bowel training diet, like CHO, reduced fiber and dairy products, or a low-FODMAP diet, has the potential to reduce gastrointestinal symptoms and improve the athletic performance of EA.

CONCLUSIONS

We found that low-FODMAP diets, gut training with CHO intake, and decreased fiber and dairy intake may have favorable effects in preventing GISs. No studies support a gluten-free diet in reducing GISs in EAs.

Development of a low-fructose carbohydrate gel for exercise application

This study aimed to develop a low-fructose (<3 g/serve) carbohydrate (CHO) gel for athletes. Various prototypes with 30 g CHO/serve and differing water content (12 %, 21 %, 32 %, 39 % w/v) were created and evaluated for sensory attributes. The final gel contained 62.1 ± 0.2 g CHO/100 g with 0.17 % w/w fructose. Endurance athletes (n = 20) underwent a feeding-challenge protocol, ingesting 30 g gel every 20 min during 2 h of running (60 %V ˙ O2max), followed by a 1 h self-paced distance test. Blood glucose increased significantly from baseline (4.0 ± 0.9 vs. 6.6 ± 0.6 mmol/L, p < 0.001) and remained elevated after the distance test (4.9 ± 0.7 mmol/L, p < 0.05). Breath hydrogen levels increased (5 ± 4 ppm, p < 0.05) without substantial CHO malabsorption detected. Gastrointestinal symptoms (GIS) increased during exercise but were mild. The low-fructose CHO gel demonstrated good tolerance, promoting glucose availability without severe GIS or CHO malabsorption.

Current and future pharmacotherapies for the management of constipation-predominant irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder affecting 9-23% of the world's population, with a higher prevalence among women. IBS is a complex disorder influenced by psychosocial, physiological, and genetic factors, exacerbated by stress.

AREAS COVERED

Research confirms that the most common subtype of IBS is IBS-C. Therefore, new therapies are being developed to speed up bowel movement and reduce constipation, with drugs such as linaclotide, plecanatide, lubiprostone, or tegaserod available to reduce IBS-C symptoms. In addition, patients' condition is improved by foods rich in fiber and low in FODMAP and the use of biotics.

EXPERT OPINION

The topic is of great importance due to the growing number of patients suffering from IBS-C and its significant impact on quality of life. Current clinical trials of new therapeutic options are not too successful, and it seems that one of the plausible treatment options could be the multi-drug cocktail with some, or perhaps even all its ingredients emerging from drug re-purposing. Another important path that needs to be explored further in IBS-C patients is the adjustment of dietary habits and/or introduction of dietary or nutritional intervention.

Effect of fibre fortification of low FODMAP pasta

Irritable bowel syndrome (IBS) is a condition affecting the digestive system and can be triggered by several different factors, including diet. To ease symptoms of IBS, a diet low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) is often recommended. Pasta, as a staple food in the Western World, is naturally high in FODMAPs. This study investigates the impact of insoluble and soluble dietary fibre ingredients in low-FODMAPs pasta. The assessment included physicochemical, sensory, and nutritional quality. Soluble fibre strengthened gluten network, which caused a lower cooking loss and a lower release of sugars during in vitro starch digestion. Insoluble fibre interfered with the gluten network development to a higher extent causing a higher sugar release during digestion. This study reveals the most suitable fibre ingredients for the development of pasta with elevated nutritional value and sensory characteristics compared to commercial products on the market. This type of pasta has a high potential of being suitable for IBS patients.

Evolution, adaptation, and new applications of the FODMAP diet

The FODMAP diet has been a treatment of irritable bowel syndrome (IBS) for many years. Rigorous scientific evaluation and clinical application of the FODMAP diet have generated deep understanding regarding clinical efficacy, mechanisms of action, and potential adverse effects of this dietary approach. In turn, this knowledge has allowed fine-tuning of the diet to optimize treatment benefits and minimize risks, in the form of the traditional three-phase diet; the FODMAP-gentle approach, which is a less restrictive iteration; and a proposed FODMAP-modified, Mediterranean-style diet which endeavours to optimise both gastrointestinal symptoms and other health parameters. Furthermore, recognition that IBS-like symptoms feature in other conditions has seen the FODMAP diet tested in non-IBS populations, including in older adults with diarrhea and women with endometriosis. These areas represent new frontiers for the FODMAP diet and a space to watch as future research evaluates the validity of these novel clinical applications.

A Review of the Efficacy of the Low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Diet in Managing Gastrointestinal Symptoms Related to Cancer Treatment

The low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, designed to alleviate symptoms in individuals with irritable bowel syndrome (IBS), focuses on limiting the consumption of poorly absorbed fermentable carbohydrates known as FODMAP. These FODMAP are believed to be the primary triggers for food-related gastrointestinal symptoms in functional gastrointestinal disorders. However, there is currently insufficient direct evidence investigating the role of low FODMAP diets in cancer patients undergoing treatment. This review aims to summarize the current evidence on the low FODMAP diet and its potential implications for cancer patients in terms of treatment outcomes, alleviating gastrointestinal symptoms, and overall health. A systematic literature search was conducted using databases, including PubMed, Scopus, Google Scholar, Web of Science, and Cochrane. Five studies met the criteria for inclusion in the review, and these studies covered rectal toxicity during radiotherapy, gastrointestinal symptoms in colorectal cancer patients, acute gastrointestinal toxicity during pelvic external beam radiotherapy, symptoms in patients with radiation-induced enteropathy, and chronic gastrointestinal sequelae resulting from pelvic organ cancer treatment. The available evidence suggests that a low FODMAP diet may offer advantages in reducing rectal gas and volume during radiotherapy, alleviating diarrhea symptoms, reducing symptom deterioration, and improving quality of life. However, these studies highlight the need for large-scale randomized trials, long-term follow-up, and guidelines to establish the efficacy, safety, and implementation strategies of the low FODMAP diet in different cancer contexts and patient populations. While preliminary findings reported some possible benefits of a low FODMAP diet for certain cancer patients, rigorous studies with large sample sizes are needed to provide more robust evidence. Further research is warranted to optimize the utilization of this diet as an adjunctive intervention for managing gastrointestinal symptoms in this population.

Diet and Nutrition in Inflammatory Bowel Disease: A Review of the Literature

Diet is thought to contribute to the development of inflammatory bowel disease (IBD) and may act as a mediator of inflammation in patients with IBD. Patients commonly associate their diet with symptoms and inquire about dietary modifications to manage their IBD. Without clinical guidelines and well-established nutritional data, healthcare providers managing patients with IBD may find it difficult to provide recommendations. Strong evidence for enteral nutrition, particularly in the pediatric population, has been established in Crohn's disease (CD) as a therapeutic option. Enteral nutrition may also serve as an adjunct to an exclusion diet. Recent studies such as the randomized trial comparing the Specific Carbohydrate Diet to a Mediterranean Diet in CD patients provide additional insights in forming dietary plans. A low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet in quiescent IBD and an anti-inflammatory diet have also been explored as adjunctive therapies. In this review, we discuss the latest evidence for the role of diet in IBD both as a therapeutic modality and as an opportunity to provide patient-centered care.

Getting the BS out of Irritable Bowel Syndrome with Diarrhea (IBS-D): Let's Make a Diagnosis

PURPOSE OF REVIEW

Irritable bowel syndrome with diarrhea (IBS-D) is diagnosed when chronic symptoms of abdominal pain accompany loose stools, and alarm features, such as fever, anemia, rectal bleeding, and weight loss are absent. This combination of symptoms makes structural disorders, such as inflammatory bowel disease or cancer, unlikely, but does not exclude other conditions that cause these symptoms. The question is whether making a "positive diagnosis" of IBS-D based on symptoms alone and instituting therapy based on that diagnosis still makes sense.

RECENT FINDINGS

Clinical observations suggest that at least two-thirds of cases of IBS-D can be explained by three mechanisms: a) food intolerances (~ 30-40%), b) bile acid diarrhea (~ 20-30%), and c) disturbed microbial flora (~ 15-20%). Other conditions that are less frequent but can cause IBS symptoms or be confused with IBS include: celiac disease, microscopic colitis, mastocytosis/mast cell activation, and drug side-effects. Many cases of IBS-D have a discoverable, underlying cause that can direct therapy more efficiently.

Higher Short-Chain Fermentable Carbohydrates Are Associated with Lower Body Fat and Higher Insulin Sensitivity in People with Prediabetes

The quality of carbohydrates has metabolic consequences in people with prediabetes. However, the causality of short-chain fermentable carbohydrate intakes and metabolic parameters has not been explored in the prediabetic or diabetic population. We investigated associations between different types of carbohydrates, including fermentable oligosaccharides, disaccharides, monosaccharides, polyols (FODMAPs), and polysaccharides (dietary fibre), and body composition and glucose/insulin responses in subjects with prediabetes. In this prospective cross-sectional study, 177 subjects with impaired glucose tolerance (IGT) (mean age: 60 (54-62) years, 41% men) underwent an assessment of body composition and completed six-point oral glucose tolerance tests (OGTT), Homeostatic Model Assessment of Insulin Resistance (HOMA2-IR), insulin sensitivity, detailed 3-day food records, and physical activity questionnaire. Daily habitual FODMAP intake decreased progressively with increasing BMI, ranging from 7.9 (6.2-12.7) g/d in subjects with normal BMI and 6.6 (4.6-9.9) g/d in subjects with overweight to 5.8 (3.8-9.0) g/d in subjects with obesity (p = 0.038). After adjustment for age and gender, galactooligosaccharides (GOSs) were negatively correlated with body fat (Standardised Beta coefficient β = -0.156, p = 0.006) and positively associated with insulin sensitivity (β = 0.243, p = 0.001). This remained significant after adjustment for macronutrients, fibre, and physical activity (p = 0.035 and p = 0.010, respectively). In individuals with IGT, higher dietary GOS intake was associated with lower body fat and higher insulin sensitivity independent of macronutrients and fibre intake, calling for interventional studies to evaluate the effect of FODMAP intake in prediabetes.

Exploring the Nutrition Strategies Employed by Ultra-Endurance Athletes to Alleviate Exercise-Induced Gastrointestinal Symptoms-A Systematic Review

(1) Background: Participation in ultra-endurance sports, particularly ultra-running, has increased over the previous three decades. These are accompanied by high energetic demands, which may be further exacerbated by extreme environmental conditions. Preparation is long-term, comprising of sufficient exercise management, supportive dietary habits, and nutritional intakes for optimal adaptations. Gastrointestinal symptoms are often cited as causing underperformance and incompletion of events. Though the majority do not pose serious long-term health risks, they may still arise. It has been suggested that the nutritional interventions employed by such athletes prior to, during, and after exercise have the potential to alter symptom incidence, severity, and duration. A summary of such interventions does not yet exist, making it difficult for relevant personnel to develop recommendations that simultaneously improve athletic performance by attenuating gastrointestinal symptoms. The aim of this research is to systematically review the literature investigating the effects of a nutrition intervention on ultra-endurance athletes exercise-induced gastrointestinal symptom incidence, severity, or duration. (2) Methods: A systematic review of the literature was conducted (PubMed, CINAHL, Web of Science, and Sports Discus) in January 2023 to investigate the effects of various nutrition interventions on ultra-endurance athletes' (regardless of irritable bowel syndrome diagnosis) exercise-induced gastrointestinal symptoms. Variations of key words such as "ultra-endurance", "gastrointestinal", and "nutrition" were searched. The risk of bias in each paper was assessed using the ADA quality criteria checklist. (3) Results: Of the seven eligible studies, one was a single field-based case study, while the majority employed a crossover intervention design. A total of n = 105 participants (n = 50 male; n = 55 female) were included in this review. Practicing a diet low in short-chain, poorly absorbed carbohydrates, known as fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), as well as employing repetitive gut challenges of carbohydrates, remain the most promising of strategies for exercise-induced gastrointestinal symptom management. (4) Conclusion: Avoiding high-FODMAP foods and practicing repetitive gut challenges are promising methods to manage gastrointestinal symptoms. However, sample sizes are often small and lack supportive power calculations.

The Low-FODMAP Diet, IBS, and BCFAs: Exploring the Positive, Negative, and Less Desirable Aspects-A Literature Review

The literature about the association of branched short-chain fatty acids (BCFAs) and irritable bowel syndrome (IBS) is limited. BCFAs, the bacterial products of the catabolism of branched-chain amino acids, are proposed as markers for colonic protein fermentation. IBS is a gastrointestinal disorder characterized by low-grade inflammation and intestinal dysbiosis. The low-FODMAP diet (LFD) has increasingly been applied as first-line therapy for managing IBS symptoms, although it decreases the production of short-chain fatty acids (SCFA), well known for their anti-inflammatory action. In parallel, high protein consumption increases BCFAs. Protein fermentation alters the colonic microbiome through nitrogenous metabolites production, known for their detrimental effects on the intestinal barrier promoting inflammation. Purpose: This review aims to explore the role of BCFAs on gut inflammation in patients with IBS and the impact of LFD in BCFAs production. Methods: A literature search was carried out using a combination of terms in scientific databases. Results: The included studies have contradictory findings about how BCFAs affect the intestinal health of IBS patients. Conclusions: Although evidence suggests that BCFAs may play a protective role in gut inflammation, other metabolites of protein fermentation are associated with gut inflammation. Further research is needed in order to clarify how diet protein composition and, consequently, the BCFAs are implicated in IBS pathogenesis or in symptoms management with LFD+.

IBS randomized study: FODMAPs alter bile acids, phenolic- and tryptophan metabolites, while gluten modifies lipids

Diet is considered a culprit for symptoms in irritable bowel syndrome (IBS), although the mechanistic understanding of underlying causes is lacking. Metabolomics, i.e., the analysis of metabolites in biological samples may offer a diet-responsive fingerprint for IBS. Our aim was to explore alterations in the plasma metabolome after interventions with fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) or gluten versus control in IBS, and to relate such alterations to symptoms. People with IBS (n = 110) were included in a double-blind, randomized, crossover study with 1-wk provocations of FODMAPs, gluten, or placebo. Symptoms were evaluated with the IBS severity scoring system (IBS-SSS). Untargeted metabolomics was performed on plasma samples using LC-qTOF-MS. Discovery of metabolite alterations by treatment was performed using random forest followed by linear mixed modeling. Associations were studied using Spearman correlation. The metabolome was affected by FODMAP [classification rate (CR) 0.88, P < 0.0001], but less by gluten intake CR 0.72, P = 0.01). FODMAP lowered bile acids, whereas phenolic-derived metabolites and 3-indolepropionic acid (IPA) were higher compared with placebo. IPA and some unidentified metabolites correlated weakly to abdominal pain and quality of life. Gluten affected lipid metabolism weakly, but with no interpretable relationship to IBS. FODMAP affected gut microbial-derived metabolites relating to positive health outcomes. IPA and unknown metabolites correlated weakly to IBS severity. Minor symptom worsening by FODMAP intake must be weighed against general positive health aspects of FODMAP. The gluten intervention affected lipid metabolism weakly with no interpretable association to IBS severity. Registration: www.clinicaltrials.gov as NCT03653689.NEW & NOTEWORTHY In irritable bowel syndrome (IBS), fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) affected microbial-derived metabolites relating to positive health outcomes such as reduced risk of colon cancer, inflammation, and type 2 diabetes, as shown in previous studies. The minor IBS symptom induction by FODMAP intake must be weighed against the positive health aspects of FODMAP consumption. Gluten affected lipids weakly with no association to IBS severity.

Personalized Diets based on the Gut Microbiome as a Target for Health Maintenance: from Current Evidence to Future Possibilities

Recently, the concept of personalized nutrition has been developed, which states that food components do not always lead to the same metabolic responses, but vary from person to person. Although this concept has been studied based on individual genetic backgrounds, researchers have recently explored its potential role in the gut microbiome. The gut microbiota physiologically communicates with humans by forming a bidirectional relationship with the micronutrients, macronutrients, and phytochemicals consumed by the host. Furthermore, the gut microbiota can vary from person to person and can be easily shifted by diet. Therefore, several recent studies have reported the application of personalized nutrition to intestinal microflora. This review provides an overview of the interaction of diet with the gut microbiome and the latest evidence in understanding the inter-individual differences in dietary responsiveness according to individual baseline gut microbiota and microbiome-associated dietary intervention in diseases. The diversity of the gut microbiota and the presence of specific microorganisms can be attributed to physiological differences following dietary intervention. The difference in individual responsiveness based on the gut microbiota has the potential to become an important research approach for personalized nutrition and health management, although further well-designed large-scale studies are warranted.

Effectiveness of diet, psychological, and exercise therapies for the management of bile acid diarrhoea in adults: A systematic review

BACKGROUND

Bile acid diarrhoea (BAD) causes chronic diarrhoea and is primarily treated pharmacologically. This systematic review aimed to evaluate the effectiveness of non-pharmacological therapies for evidence-based management of BAD in adults.

METHODS

A systematic review of the medical literature was performed from 1975 to 13 July 2021 to identify studies on diet, psychological, and exercise therapies that met diagnostic criteria for BAD in adults with diarrhoea. Effectiveness was judged by responder or improvement in diarrhoea at study endpoint according to each study's definition of diarrhoea. Therapeutic effect on abdominal pain and flatulence was also measured. Risk of bias was assessed using the Risk Of Bias In Non-Randomised Studies of Interventions tool. A narrative review was conducted using 'Synthesis Without Meta-analysis' guidance. Certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Eight prospective cohort studies were identified on diet therapies from 2 weeks to over 2 years involving 192 patients. No psychological or exercise therapies were found. Carbohydrate modification (one study, n = 2) in primary BAD, and dietary fat intake reductions (five studies, n = 181) and an exclusive elemental diet therapy (two studies, n = 9) in secondary BAD, showed beneficial directions of effect on diarrhoea, abdominal pain, and flatulence. Risks of bias for each study and across studies for each therapy type were serious. Certainty of the evidence was very low for all outcomes.

CONCLUSIONS

No conclusions could be drawn on the effectiveness of diet, psychological, or exercise therapies on diarrhoea, abdominal pain, and flatulence for the management of BAD in adults. High-quality randomised controlled trials are needed.

The Potential Role of Human Milk Oligosaccharides in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is the most common gastrointestinal (GI) disorder in Western populations and therefore a major public health/economic concern. However, despite extensive research, psychological and physiological factors that contribute to the aetiology of IBS remain poorly understood. Consequently, clinical management of IBS is reduced to symptom management through various suboptimal options. Recent evidence has suggested human milk oligosaccharides (HMOs) as a potential therapeutic option for IBS. Here, we review literature concerning the role of HMOs in IBS, including data from intervention and in vitro trials. HMO supplementation shows promising results in altering the gut microbiota and improving IBS symptoms, for instance by stimulating bifidobacteria. Further research in adults is required into HMO mechanisms, to confirm the preliminary results available to date and recommendations of HMO use in IBS.

The low-FODMAP diet and the gluten-free diet in the management of functional abdominal bloating and distension

This review summarizes current knowledge on the role of low-FODMAP diet and gluten-free diet in functional abdominal bloating and distension, an emerging disorder of gut-brain interaction characterized by remarkable costs for healthcare systems and a significant impact on the patient's quality of life. Ingested food plays a key role in the pathophysiology of disorders of gut-brain interaction as up to 84% of patients with irritable bowel syndrome (IBS) report food-triggered symptoms. Potential pathogenetic mechanisms of food-related symptoms in these patients are discussed, focusing on bloating and abdominal distension. These mechanisms provide the rationale for dietary treatment in patients with functional abdominal bloating and distension. The role of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) and gluten in functional abdominal bloating and distension is examined. Current literature evaluating the efficacy of the low-FODMAP diet and the gluten-free diet in abdominal bloating and distension is analyzed. Available evidence originates mainly from studies on patients with IBS, since clinical studies on selected cohorts of patients with only functional abdominal bloating and distension have been missing to date. Promising evidence on the potential efficacy of the low-FODMAP diet in functional abdominal bloating and distension is provided by the reduction of the bloating observed in patients with IBS. Regarding the gluten-free diet, there is insufficient evidence to recommend it to reduce bloating and abdominal distension. In conclusion, this review asserts the need for a close collaboration with experts in nutrition to optimize the management of these patients and reduce the risks associated with elimination diets.

In Vitro Efficacy of Targeted Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols Enzymatic Digestion in a High-Fidelity Simulated Gastrointestinal Environment

Background and Aims

Irritable bowel syndrome (IBS) is characterized by abdominal pain and changes in bowel habits. Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are poorly absorbed short-chain carbohydrates that may drive commensal microbial gas production, promoting abdominal pain in IBS. Low-FODMAP diet can result in symptomatic improvement in 50%-80% of IBS patients. However, this diet is not meant to be sustained long term, with concern for downstream nutrition and microbial issues. In this study, we evaluate the function of a targeted FODMAP enzymatic digestion food supplement FODMAP enzymatic digestion (FODZYME) containing a fructan-hydrolase enzyme (with significant inulinase activity) in a simulated gastrointestinal environment.

Methods

Using SHIME (Simulator of the Human Intestinal Microbial Ecosystem), a multi-compartment simulator of the human gut, FODZYME dose finding assay in modeled gastrointestinal conditions assessed enzymatic ability to hydrolyze 3 g of inulin. Full intestinal modeling assessing digestion of inulin, absorption of fructose, gas production, and other measures of commensal microbial behavior was completed using 1.125 g of FODZYME.

Results

After 30 minutes, 90% of the inulin was converted to fructose by 1.125 g of FODZYME. Doubling dosage showed no significant improvement in conversion, whereas a half dose decreased performance to 77.2%. Seventy percent of released fructose was absorbed during simulated small intestinal transit, with a corresponding decrease in microbial gas production, and a small decrease in butyrate and short-chain fatty acid production.

Conclusion

FODZYME specifically breaks down inulin in representative gastrointestinal conditions, resulting in decreased gas production while substantially preserving short-chain fatty acid and butyrate production in the model colon. Our results suggest dietary supplementation with FODZYME would decrease intestinal FODMAP burden and gas production.

Dietary Patterns and Gut Microbiota Changes in Inflammatory Bowel Disease: Current Insights and Future Challenges

Inflammatory bowel disease (IBD) is a result of a complex interplay between genes, host immune response, gut microbiota, and environmental factors. As one of the crucial environmental factors, diet plays a pivotal role in the modulation of gut microbiota community and the development of IBD. In this review, we present an overview of dietary patterns involved in the pathogenesis and management of IBD, and analyze the associated gut microbial alterations. A Westernized diet rich in protein, fats and refined carbohydrates tends to cause dysbiosis and promote IBD progression. Some dietary patterns have been found effective in obtaining IBD clinical remission, including Crohn's Disease Exclusion Diet (CDED), Mediterranean diet (MD), Anti-Inflammatory Diet (AID), the low-"Fermentable Oligo-, Di-, Mono-saccharides and Polyols" (FODMAP) diet, Specific Carbohydrate Diet (SCD), and plant-based diet, etc. Overall, many researchers have reported the role of diet in regulating gut microbiota and the IBD disease course. However, more prospective studies are required to achieve consistent and solid conclusions in the future. This review provides some recommendations for studies exploring novel and potential dietary strategies that prevent IBD.

Dairying, diseases and the evolution of lactase persistence in Europe

In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years1. Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions2,3. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank4,5 cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.

Global Research Trends in Irritable Bowel Syndrome: A Bibliometric and Visualized Study

Background

There are about 10–23% of adults worldwide suffering from irritable bowel syndrome (IBS). Over the past few decades, there are many aspects of uncertainty regarding IBS leading to an ongoing interest in the topic as reflected by a vast number of publications, whose heterogeneity and variable quality may challenge researchers to measure their scientific impact, to identify collaborative networks, and to grasp actively researched themes. Accordingly, with help from bibliometric approaches, our goal is to assess the structure, evolution, and trends of IBS research between 2007 and 2022.

Methods

The documents exclusively focusing on IBS from 2007 to 2022 were retrieved from the Science Citation Index Expanded of the Web of Science Core Collection. The annual productivity of IBS research, and the most prolific countries or regions, authors, journals and resource-, intellectual- and knowledge-sharing in IBS research, as well as co-citation analysis of references and keywords were analyzed through Microsoft Office Excel 2019, CiteSpace, and VOSviewer.

Results

In total, 4,092 publications were reviewed. The USA led the list of countries with the most publications (1,226, 29.96%). Mayo Clinic contributed more publications than any other institution (193, 4.71%). MAGNUS SIMREN stood out as the most active and impactful scholar with the highest number of publications and the greatest betweenness centrality value. The most high-yield journal in this field was Neurogastroenterology and motility: the official journal of the European Gastrointestinal Motility Society (275, 6.72%). Gastroenterology had the most co-citations (3,721, 3.60%). Keywords with the ongoing strong citation bursts were chromogranin A, rat model, peptide YY, gut microbiota, and low-FODMAP diet, etc.

Conclusion

Through bibliometric analysis, we gleaned deep insight into the current status of literature investigating IBS for the first time. These findings will be useful to scholars interested in understanding the key information in the field, as well as identifying possible research frontiers.

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

BACKGROUND AND AIM

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

METHODS

Published literature and clinical experience were reviewed.

RESULTS

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

CONCLUSIONS

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

Irritable bowel syndrome and diet

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder (FGID) characterized by chronic abdominal pain and altered bowel habits. The diagnosis of IBS is based on the presence of defined clinical Rome IV criteria in the absence of alarm features. The majority of patients with IBS report of food triggers eliciting typical IBS symptoms and trying to modify their dietary intake.

RECENT FINDINGS

FGID including IBS are defined as disorders of the gut-brain interaction. A large proportion of individuals with IBS link their symptoms to dietary factors, and recent clinical studies have shown benefits of a diet low in FODMAPs (Fermentable Oligo-, Di-, and Monosaccharides and Polyols) on IBS symptoms and quality of life. Dietary interventions mediate directly changes of luminal gut contents affecting chemosensing-enteroendocrine cells in the modulation of the gut brain microbiome axis in IBS patients. Long-term assessment of clinical outcomes in patients on a low FODMAP diet is needed. Professional guidelines have incorporated the suggestion to offer IBS patients a diet low in FODMAPs.

SUMMARY

The FGIDs, including IBS, are defined as gut-brain disorders. Low FODMAP diet has been shown in clinical trials to reduce IBS symptoms but long-term efficacy and nutritional side-effects remain uncertain.

The potential role of lactulose pharmacotherapy in the treatment and prevention of diabetes

The non-absorbable disaccharide lactulose is mostly used in the treatment of various gastrointestinal disorders such as chronic constipation and hepatic encephalopathy. The mechanism of action of lactulose remains unclear, but it elicits more than osmotic laxative effects. As a prebiotic, lactulose may act as a bifidogenic factor with positive effects in preventing and controlling diabetes. In this review, we summarized the current evidence for the effect of lactulose on gut metabolism and type 2 diabetes (T2D) prevention. Similar to acarbose, lactulose can also increase the abundance of the short-chain fatty acid (SCFA)-producing bacteria Lactobacillus and Bifidobacterium as well as suppress the potentially pathogenic bacteria Escherichia coli. These bacterial activities have anti-inflammatory effects, nourishing the gut epithelial cells and providing a protective barrier from microorganism infection. Activation of peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP1) can influence secondary bile acids and reduce lipopolysaccharide (LPS) endotoxins. A low dose of lactulose with food delayed gastric emptying and increased the whole gut transit times, attenuating the hyperglycemic response without adverse gastrointestinal events. These findings suggest that lactulose may have a role as a pharmacotherapeutic agent in the management and prevention of type 2 diabetes via actions on the gut microbiota.

SEVERITY OF IRRITABLE BOWEL SYNDROME SYMPTOMS AND FODMAPS INTAKE IN UNIVERSITY STUDENTS

BACKGROUND

Irritable bowel syndrome (IBS) symptoms such as diarrhea, bloating and abdominal pain can reduce University student's productivity and learning ability. One of the possible treatments for IBS is the temporarily exclusion of foods that have a high content of short-chain fermentable carbohydrates, the fermentable, oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs).

OBJECTIVE

This study aimed to assess University student's intake of foods that are rich in FODMAPs, looking for possible associations with the severity of IBS symptoms.

METHODS

A cross-sectional study was carried out, with undergraduate students from a private University in the city of São Paulo, Brazil, aged between 19 and 46 years old and that were enrolled in different courses and stages. Students were invited to participate and those who gave their formal consent were included in this research. A sociodemographic and lifestyle questionnaire was applied, in addition to the Gastrointestinal Symptom Rating Scale - GSRS. Students also responded a short Food Frequency Questionnaire, developed to investigate habitual FODMAPs intake of Brazilian adult population. Spearman's correlation analysis between the student's GSRS scores and the frequency of foods rich in FODMAPs intake were performed in SPSS v.21.

RESULTS

Fifty-six students were interviewed, with mean age of 21.4 years old (SD=4.41), with a predominance of women (76.8%). The GSRS results showed that 58.9% of students felt minimal to moderate abdominal discomfort and 14.3% had moderately severe to very severe abdominal pain during the prior week to the interview. Besides abdominal pain, the gastrointestinal symptoms that were most reported by students were flatulence (98.2%), stomach rumbling (89.3%) and eructations (85.7%). Greater symptom severity was observed in women (P=0.004) and sedentary students (P=0.003). Regarding FODMAPs consumption, honey (P=0.04), chocolate (P=0.03) and milk table cream (P=0.001) intakes were positively correlated with the greater severity of symptoms.

CONCLUSION

Although clinical diagnosis is necessary to establish IBS, 73.2% of the students presented minimal to very severe abdominal pain during the prior week. Female had sedentary students had greater severity of gastrointestinal symptoms. A low FODMAP diet, well oriented, could bring some symptoms relief to these University students.

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

BACKGROUND AND AIM

Low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet improves irritable bowel syndrome (IBS) symptoms. Data on long-term "modified" FODMAP diet are emerging. We aimed to assess efficacy and acceptability of short-term "strict" low FODMAP diet (LFD) and long-term "modified" FODMAP diet in patients with diarrhea-predominant IBS (IBS-D).

METHODS

This prospective randomized trial included patients with IBS-D (Rome IV) and IBS severity scoring system (IBS-SSS) ≥ 175. In phase I (4 weeks), patients were randomized to strict LFD and traditional dietary advice (TDA) groups. From 4 to 16 weeks, LFD group was advised systematic reintroduction of FODMAPs ("modified" FODMAP diet). Response was defined as > 50-point reduction in IBS-SSS.

RESULTS

Of the total 166 patients with IBS-D screened, 101 (mean age 41.9 ± 17.1 years, 58% male) were randomized to LFD (n = 52) and TDA (n = 49) groups. Both at 4 and 16 weeks, total IBS-SSS and IBS quality of life score reduced significantly in both groups, but there was significantly greater reduction in LFD group. By intention-to-treat analysis, responders in LFD group were significantly higher than TDA group (4 weeks-62.7% [32/51] vs 40.8% [20/49], respectively, P = 0.0448; 16 weeks-52.9% [27/51] vs 30.6% [15/49], respectively; P = 0.0274). Compliance to LFD was 93% at 4 weeks and 64% at 16 weeks. Energy, carbohydrate, fat, and fiber intake showed reduction in LFD group at 4 weeks, which improved till 16 weeks.

CONCLUSIONS

Strict LFD for short-term and "modified" LFD for long term in IBS-D patients is acceptable and leads to significant improvement in symptoms and quality of life.

[Phytotherapeutische Ansätze zur Behandlung des laryngopharyngealen Reflux in der HNO-Praxis]

Der gastroösophageale Reflux, auch GERD genannt (gastroesophageal reflux disease) ist mit einer Prävalenz von 20-30% der erwachsenen Bevölkerung ein weit verbreitetes Problem. Davon abzugrenzen ist der häufig in der HNO-Praxis anzutref-fende laryngopharyngeale Reflux (LPR), bei dem es sich um eine durch den Magensäurereflux bedingte Entzündung der oberen Atemwege handelt. Die Unterschiede im klinischen Bild charakterisieren die widersprüchliche Beziehung der beiden klinischen Entitäten und erschweren die Diagnosestellung. Darüber hinaus muss ein besonderes Augenmerk auf Beschwerden des Magen- und Darmtrakts gelegt und deren Behandlung nicht vernachlässigt werden. Neben diätetischen Ratschlägen zählen einige pflanzliche Arzneimittel zu den Therapieoptionen. Alginate, die ein Aufstossen verhindern, bewähren sich in der Praxis. Kombinationsarzneimittel aus der europäischen und tibetischen Tradition spielen eine wesentliche Rolle in der Behandlung, nicht nur des LPR sondern auch bei Verdauungsproblemen des oberen und unteren Verdauungstrakts, wie Reizmagen und Reizdarm.

The gastroesophageal reflux, also called GERD (gastroesophageal reflux disease), is a widespread problem with 20–30% of the adult population concerned. The laryngopharyngeal reflux (LPR), which is an inflammation of the upper respiratory system due to reflux of gastric acids, is a frequently encountered problem of the gastrointestinal practitioner and should be separated from GERD. The differences in the clinical image characterize the contradictory relationship of both clinical entities and complicate the diagnosis. In addition, the focus should also be turned on eventual disorders of the gastrointestinal tract and, if necessary, they should be treated, too. Besides dietetic advice some herbal medicines belong to the therapeutic options. Alginates, which prevent reflux, have proved a great value in the practice. Multicomponent mixtures originating from the European and Tibetan herbal medicine traditions play a major role in the treatment, not only for LPR, but also for the upper and lower digestive pathologies such as functional dyspepsia and irritable colon.

An evaluation of dietary adequacy among patients with constipation-predominant irritable bowel syndrome in Malaysia

Background/Aims

Substantial proportions of patients with constipation-predominant irritable bowel syndrome (IBS-C) linked their symptoms with particular intake of foods. However, there is lack of current data regarding the intake among IBS-C patients before any dietary interventions. Thus, this study aimed to evaluate the dietary adequacy among IBS-C against the standard recommended nutrient intake (RNI) and healthy controls.

Methods

A retrospective case-control study was conducted involving IBS-C patients and healthy control subjects. A validated 126-food items frequency questionnaire was administered to all the subjects to assess their dietary intake, guided by dietitians. The calculated nutrients intake for IBS-C patients was then compared against the standard RNI and healthy controls.

Results

A total of 306 subjects were recruited, among which 218 were diagnosed with IBS-C and 88 were included as healthy controls. IBS-C patients had significantly lower intake of wholegrain products, fried foods, dairy products, fruits, and vegetables compared to healthy controls. The daily intake of energy, certain macronutrients, and micronutrients among IBS-C patients was significantly lower than the healthy subjects. Less than 5% of IBS-C patients and healthy subjects achieved the standard recommendation for dietary fiber. Also, various vitamin intake (B₁, B₂, B₆, folate, B₁₂, E, K, and potassium) among IBS-C patients did not meet the standard RNI.

Conclusions

Dietary intakes of IBS-C patients did not meet the recommended intake for Malaysian and showed the nutritional inadequacies compared to the control subjects. Our study highlighted the importance of dietary evaluation prior to planning strategies for dietary intervention targeting IBS-C patients.

Behavioral and Diet Therapies in Integrated Care for Patients With Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common, symptom-based condition that has negative effects on quality of life and costs health care systems billions of dollars each year. Until recently, management of IBS has focused on over-the-counter and prescription medications that reduce symptoms in fewer than one-half of patients. Patients have increasingly sought natural solutions for their IBS symptoms. However, behavioral techniques and dietary modifications can be effective in treatment of IBS. Behavioral interventions include gastrointestinal-focused cognitive behavioral therapy and gut-directed hypnotherapy to modify interactions between the gut and the brain. In this pathway, benign sensations from the gut induce maladaptive cognitive or affective processes that amplify symptom perception. Symptoms occur in response to cognitive and affective factors that trigger fear of symptoms or lack of acceptance of disease, or from stressors in the external environment. Among the many dietary interventions used to treat patients with IBS, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols is the most commonly recommended by health care providers and has the most evidence for efficacy. Patient with IBS who choose to follow a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols should be aware of its 3 phases: restriction, reintroduction, and personalization. Management of IBS should include an integrated care model in which behavioral interventions, dietary modification, and medications are considered as equal partners. This approach offers the greatest likelihood for success in management of patients with IBS.

Is Gluten the Only Culprit for Non-Celiac Gluten/Wheat Sensitivity?

The gluten-free diet (GFD) has gained increasing popularity in recent years, supported by marketing campaigns, media messages and social networks. Nevertheless, real knowledge of gluten and GF-related implications for health is still poor among the general population. The GFD has also been suggested for non-celiac gluten/wheat sensitivity (NCG/WS), a clinical entity characterized by intestinal and extraintestinal symptoms induced by gluten ingestion in the absence of celiac disease (CD) or wheat allergy (WA). NCG/WS should be regarded as an "umbrella term" including a variety of different conditions where gluten is likely not the only factor responsible for triggering symptoms. Other compounds aside from gluten may be involved in the pathogenesis of NCG/WS. These include fructans, which are part of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), amylase trypsin inhibitors (ATIs), wheat germ agglutinin (WGA) and glyphosate. The GFD might be an appropriate dietary approach for patients with self-reported gluten/wheat-dependent symptoms. A low-FODMAP diet (LFD) should be the first dietary option for patients referring symptoms more related to FODMAPs than gluten/wheat and the second-line treatment for those with self-reported gluten/wheat-related symptoms not responding to the GFD. A personalized approach, regular follow-up and the help of a skilled dietician are mandatory.

Diet Advice for Crohn's Disease: FODMAP and Beyond

Crohn's disease (CD) is a chronic, progressive, and destructive granulomatous inflammatory bowel disorder that can involve any part of the gastrointestinal tract. It has been presumed that different types of diet might improve gastrointestinal symptoms in CD patients. The aim of this review was to clarify the efficiency and indications of a low-"fermentable oligo-, di-, mono-saccharides and polyols" (FODMAP) diet (LFD) in CD and to further analyze the available data on other types of diets. PubMed, Cochrane Library, EMBASE and WILEY databases were screened for relevant publications regarding the effect of FODMAP diets on CD. Our search identified 12 articles analyzing the effect of an LFD in CD, 5 articles analyzing the effect of a Mediterranean diet (MD), 2 articles analyzing the effect of a vegetarian diet (VD), and 2 articles analyzing the effect of a low-lactose diet (LLD). The majority of the studies included in this review show the significant efficiency of the LFD in CD patients. We found significant evidence demonstrating that the LFD has a favorable impact on gastrointestinal symptoms in CD patients. Notwithstanding the evidence, it remains to be established if an LFD is more efficient than other types of diets in the short term and especially in the long term.

Food Additives, Gut Microbiota, and Irritable Bowel Syndrome: A Hidden Track

The interactions between diet, gut microbiota, and irritable bowel syndrome (IBS) have many complex mechanisms that are not fully understood. Food additives are one component of the modern human diet that deserves attention from science and government policies. This review aims at identifying the current knowledge about the impact of food additives on gut microbiota and their potential role in the development of IBS. To date, few data on the effect of food additives on gut microbiota in IBS patients are available. However, exposure to food additives could induce the dysbiosis and dysregulation of gut homeostasis with an alteration of the gut barrier and activation of the immune response. These microbial changes could exacerbate the gut symptoms associated with IBS, such as visceral pain, low-grade inflammation, and changes in bowel habits. Some additives (polyols) are excluded in the low fermentable oligo-, di- and monosaccharide, and polyol (FODMAP), diets for IBS patients. Even if most studies have been performed in animals, and human studies are required, many artificial sweeteners, emulsifiers, and food colorants could represent a potential hidden driver of IBS, through gut microbiota alterations. Consequently, food additives should be preventively avoided in the diet as well as dietary supplements for patients with IBS.

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.

Determination of FODMAP contents of common wheat and rye breads and the effects of processing on the final contents

The benefits of a diet, low in fermentable oligo-, di- and monosaccharides and polyols (FODMAP) for patients suffering from irritable bowel syndrome (IBS) has been well established. Thus, the exact knowledge of the amount and composition of FODMAPs in foods is of vital importance for these patients. This study investigated the possibilities of FODMAP reduction by adjusting the processing parameters, which are feasible in practise, while still producing marketable breads. Therefore, the impact of prolonged proofing and the addition of sourdough on the FODMAPs in the final products was evaluated. High performance anion exchange chromatography was used for qualitative and quantitative analysis. A prolonged proofing time resulted in reduction of the fructan content and in consequence of the total FODMAPs. In contrast, the addition of sourdough only altered the FODMAP composition, by reducing the fructan content but increasing the mannitol content. While all the breads produced from refined wheat flour meet the low-FODMAP criteria, the breads from rye and whole meal wheat flour have to be considered as high-FODMAP, regardless of the processing conditions investigated. Breads produced from rye flour exceeded the limits for fructans and mannitol, while whole meal wheat breads were found to exceed the threshold for excess fructose. Overall, the production of low-FODMAP rye breads was identified as the biggest challenge for future research, since it could not be achieved using conventional processing parameter.

Global Dietary Patterns and Functional Gastrointestinal Disorders

Functional Gastrointestinal Disorders (FGIDs) are common. In the United States alone, approximately 25 million Americans are estimated to have at least one FGID. Nonpharmacological treatment options include psychological/behavioral approaches, and dietary interventions that can vary across countries. The aim of this review is to evaluate the available evidence for dietary interventions for the treatment of childhood FGIDs amongst various cultures and regions of the world. This review includes clinical trials of dietary therapies for the treatment of FGIDs in children posted on or before 13 July 2020 in PubMed. Overall, the consensus view suggests that the westernization of diets is linked to the development of FGIDs, and diets low in Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPs) may reduce abdominal symptoms. However, more work is needed to confirm these findings.

Fermentable carbohydrate intake and food avoidance behaviour in elderly patients with irritable bowel syndrome: A case report

Background: Fermentable carbohydrates or FODMAPs (Fermentable Oligo-, Di-, Monosaccharides, and Polyols) are short-chained, poorly absorbed carbohydrates which trigger gastrointestinal symptoms causing pain, bloating, distension, diarrhea, and constipation in Irritable Bowel Syndrome (IBS) patients. This debilitating condition has an impact on the quality of life of patients. In addition, due to lack of dietary intervention, it can result in food restriction to alleviate symptoms as patients avoid a wide variety of food and beverages. Objective: To compare FODMAP and nutrient intake, food avoidance behavior and quality of life in 2 long standing patients with IBS. Methods: Patients were selected on the basis of being diagnosed with IBS by a gastroenterologist. A 24-hour dietary recall with multiple pass method was used to assess intake. FODMAP intake was determined using published data. Symptom severity and quality of life was measured using a validated questionnaire. Meanwhile, food avoidance was assessed using a dietary trigger piloted questionnaire. Results: Two female Chinese patients with severe gastrointestinal symptoms were selected for this case series. Patient 1 was a 75-year-old female presenting with constipation-predominant IBS and patient 2 was a 61-year-old presenting with diarrhea-predominant IBS. Patient 1 had a higher energy intake: 2198 kcal, and FODMAP intake 10.6g/d, compared to patient 2 with an energy and FODMAP intake of 1800 kcal and 3.6g/d respectively. Both patients avoided a wide of range of food groups including cereals and grains, animal products, dairy and spicy foods. They also reported reduced scores for quality of life. Conclusion: Both patients had low intake of calcium as a result of food avoidance. This highlights the importance of appropriate and timely dietary intervention to this group of patients, to promote improved symptom management without compromising nutrient intake.

Diagnostic Utility of Carbohydrate Breath Tests for SIBO, Fructose, and Lactose Intolerance

BACKGROUND

Unexplained bloating, gas, and pain are common symptoms. If routine tests are negative, such patients are often labeled as irritable bowel syndrome.

AIMS

To determine the diagnostic utility of breath tests that assess for small intestinal bacterial overgrowth (SIBO), fructose or lactose intolerance, and the predictive value of symptoms.

METHODS

Patients with gas, bloating, diarrhea, abdominal pain (≥ 6 months), and negative endoscopy and radiology tests were assessed with symptom questionnaires, glucose (75 g), fructose (25 g), or lactose (25 g) breath tests. Breath tests were categorized as positive when H₂ (≥ 20 ppm) or CH₄ (≥ 15 ppm) increased above baseline values or as hypersensitive when symptoms changed significantly without rise in H₂/CH₄ or as negative.

RESULTS

1230 patients (females = 878) underwent 2236 breath tests. The prevalence of SIBO was 33% (294/883), fructose intolerance was 34% (262/763), and lactose intolerance was 44% (260/590). Hypersensitivity was found in 16% and 9%, respectively, during fructose and lactose breath tests. Although gas (89%), abdominal pain (82%), and bloating (82%) were highly prevalent, pretest symptoms or their severity did not predict an abnormal breath test, but symptoms during the breath test facilitated diagnosis of SIBO, fructose, and lactose intolerance and hypersensitivity.

CONCLUSIONS

Approximately 45% of patients with unexplained gas and bloating had SIBO, fructose, or lactose intolerance; another 9-16% had visceral hypersensitivity. Pretest symptoms were poor predictors, but symptoms during the breath tests were useful. Breath tests are safe, provide significant diagnostic yield, and could be useful in routine gastroenterology practice.

From IBS to ME - The dysbiotic march hypothesis

Irritable bowel syndrome (IBS) is often associated with other unexplained complaints like chronic fatigue syndrome (CFS), fibromyalgia and myalgic encephalopathy (ME). The pathogenesis of the relationship is unknown. Intestinal dysbiosis may be a common abnormality, but based on 1100 consecutive IBS patients examined over a nine years period, we hypothesize that the development of the disease, often from IBS to ME, actually manifests a "dysbiotic march". In analogy with "the atopic march" in allergic diseases, we suggest "a dysbiotic march" in IBS; initiated by extensive use of antibiotics during childhood, often before school age. Various abdominal complaints including IBS may develop soon thereafter, while systemic symptom like CFS, fibromyalgia and ME may appear years later.

Low FODMAP Diet: Evidence, Doubts, and Hopes

Food is often considered to be a precipitating factor of irritable bowel syndrome (IBS) symptoms. In recent years, there has been a growing interest in FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides, And Polyols), which can be found in many common foods. A low FODMAP diet (LFD) is increasingly suggested for IBS treatment. However, long-term, large, randomized controlled studies are still lacking, and certainties and doubts regarding LFDs have grown, often in a disorderly and confused manner. Some potential LFD limitations and concerns have been raised, including nutritional adequacy, cost, and difficulty in teaching the diet and maintaining it. Most of these limitations can be solved with the involvement of a skilled nutritionist, who can clearly explain the different phases of the LFD and ensure nutritional adequacy and compliance. Further studies should focus on new methods of teaching and learning the LFD and on predictors of response. Moreover, particular interest should be focused on the possible use of LFD in gastrointestinal diseases other than functional disorders and, possibly, also in non-gastrointestinal diseases. The aim of the present review was to clarify the effective and appropriate indications and limitations of an LFD and to discuss its possible future uses.

Effects of Low-FODMAPS Diet on Irritable Bowel Syndrome Symptoms and Gut Microbiome

Patients with irritable bowel syndrome (IBS) suffer from abdominal pain, bloating, and abnormal defecation. Reducing the dietary intake of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) has been shown to be beneficial in reducing IBS symptoms. However, diet modification plays an important role in the composition of colonic microbiota. Currently, the effects of a FODMAP diet on the composition of the gut microbiome are not known. We conducted a systematic review to determine (1) the effectiveness of low-FODMAPs diet to reduce symptoms of patients with IBS and (2) the association between a low-FOMAPs diet and the composition of gut microbiome. Four electronic databases were searched using key words "IBS" or "irritable bowel syndrome," and "FODMAP" or "FODMAPs" or "fermentable oligosaccharides, disaccharides, monosaccharides, and polyols," and "microbiome." Two reviewers (H.S. and Y.T.L.) selected and reviewed articles according to our inclusion criteria. A total of 87 articles were reviewed and 7 met inclusion criteria. Based on the systematic review, low FODMAPs appear to reduce gastrointestinal symptoms for a least a subset of patients with IBS. However, due to the heterogeneity of reviewed studies, the influence on patients' gut microbiome composition and/or microbiota metabolites requires additional studies.

Food Components and Dietary Habits: Keys for a Healthy Gut Microbiota Composition

The gut microbiota is a changing ecosystem, containing trillions of bacteria, continuously shaped by many factors, such as dietary habits, seasonality, lifestyle, stress, antibiotics use, or diseases. A healthy host-microorganisms balance must be respected in order to optimally maintain the intestinal barrier and immune system functions and, consequently, prevent disease development. In the past several decades, the adoption of modern dietary habits has become a growing health concern, as it is strongly associated with obesity and related metabolic diseases, promoting inflammation and both structural and behavioral changes in gut microbiota. In this context, novel dietary strategies are emerging to prevent diseases and maintain health. However, the consequences of these different diets on gut microbiota modulation are still largely unknown, and could potentially lead to alterations of gut microbiota, intestinal barrier, and the immune system. The present review aimed to focus on the impact of single food components (macronutrients and micronutrients), salt, food additives, and different dietary habits (i.e., vegan and vegetarian, gluten-free, ketogenic, high sugar, low FODMAP, Western-type, and Mediterranean diets) on gut microbiota composition in order to define the optimal diet for a healthy modulation of gut microbiota.

Low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet in children

Irritable bowel syndrome (IBS) is a lifelong condition with a high prevalence among children and adults. As the diet is a frequent factor that triggers the symptoms, it has been assumed that by avoiding the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP), the symptoms might be improved. Therefore, in the past decade, low FODMAP diet has been intensively investigated in the management of IBS. The capacity of FODMAPs to trigger the symptoms in patients with IBS was related to the stimulation of mechanoreceptors in the small and large intestine. This stimulation appears as a response to a combination of increased luminal water (the osmotic effect) and the release of gases (carbon dioxide and hydrogen) due to the fermentation of oligosaccharides and malabsorption of fructose, lactose and polyols. Numerous studies have been published regarding the efficacy of a low FODMAP diet compared to a traditional diet in releasing the IBS symptoms in adults, but there are only a few studies in the juvenile population. The aim of this review is to analyze the current data on both low FODMAP diet in children with IBS and the effects on their nutritional status and physiological development, given the fact that it is a restrictive diet.

Low FODMAP diet significantly improves IBS symptoms: an Irish retrospective cohort study

INTRODUCTION

There is growing evidence that a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) improves symptoms in irritable bowel syndrome (IBS) patients. We aimed to retrospectively investigate the effects of this diet in Irish IBS cohort over a 12-month follow-up period, including after re-introduction of the high FODMAP foods.

METHODS

All the tertiary referrals seen by an FODMAP-trained dietician were reviewed (2013-2016). Patients were evaluated for IBS symptoms by a questionnaire (four-point Likert scale). Subsequently, advice regarding the low FODMAP diet was given. Symptoms' response was assessed at 3-, 6-, and 12-month follow-up, by use of the same questionnaire. Re-introduction of high FODMAP foods was aimed to commence at the subsequent follow-up.

RESULTS

A total of 164 patients were identified. Thirty-seven patients were excluded due to failure to attend for follow-up. Hundred and twenty-seven patients (77% patients, of which 85% were female) completed the initial 3-month follow-up. Forty-five percent (74/164) and twenty-five percent (41/164) of the patients had continued follow-up at 6 and 12 months, respectively. Of the 127 patients who returned for follow-up, their commonest baseline symptoms were lethargy (92%), bloating (91%), flatulence (91%), and abdominal pain (89%). All symptoms were significantly improved at the initial follow-up (p < 0.0001 for all). Most patients (66%) were satisfied with their overall symptoms control. In patients who had a longer follow-up duration, all symptoms remained significantly improved compared to the baseline (p < 0.0001 for combined symptoms at 6 and 12 months). After re-introduction of the high FODMAP foods, all patients maintained their symptomatic response (n = 14/14 and n = 7/7 at 6- and 12-month follow-up, respectively). The best symptoms' improvement was seen in those who were fully adherent to the FODMAP diet.

CONCLUSION

In this Irish retrospective cohort study, the low FODMAP diet significantly improved all IBS symptoms at 3-, 6-, and 12-month follow-up. Following the re-introduction of the high FODMAP foods in a subgroup of patients, they were able to maintain their long-term symptomatic response up to 9 months. The low FODMAP diet might be continued for longer than 3 months; however, further studies are needed to assess the long-term safety of this diet.

Irritable bowel syndrome: how can symptoms and quality of life be improved with diet?

PURPOSE OF REVIEW

This article aims to review the current scientific evidence of dietary approaches to control the symptoms of irritable bowel syndrome (IBS).

RECENT FINDINGS

In the last decade, there was an important evolution in the study of the low fermentable oligo, di, mono-saccharides and polyols (FODMAP) diet (LFD). Current scientific evidence suggests a significant efficacy in the overall control of symptoms. LFD seems to be effective in improving quality of life. Recent studies suggest that LFD is effective and nutritionally well tolerated also in the long term, and longer adherence may contribute to greater effectiveness in improving depression. There is insufficient scientific evidence for the recommendation of gluten exclusion in IBS therapy, and some authors still suggest that the efficacy of this approach results from the limited ingestion of fructans. There is a promising efficacy of pre, pro, and symbiotic supplements, but there is no consensus on the most appropriate and effective strains in each case.

SUMMARY

Given the poor evidence and the pathophysiological variability of IBS, the interest of each therapeutic option should be always evaluated individually. Nevertheless, LFD is currently the dietary approach with a higher degree of scientific evidence.

Popular Remedies for Esophageal Symptoms: a Critical Appraisal

PURPOSE OF REVIEW

Popular remedies are of ongoing interest to patients experiencing common esophageal symptoms, particularly as typical pharmacologic interventions have been subject to increased scrutiny. Herein we summarize the available data regarding potential risks and benefits of several such remedies.

RECENT FINDINGS

With emphasis on reflux and non-cardiac chest pain, research is ongoing into the clinical utility and diverse physiologic mechanisms underlying a variety of complementary and alternative modalities, including dietary manipulation, apple cider vinegar, melatonin, acupuncture, and various herbal products (rikkunshito, STW 5, slippery elm, licorice, and peppermint oil, among others). A substantial gap persists between anecdotal and empirical understandings of the majority of non-pharmacologic remedies for esophageal symptoms. This landscape of popular treatments nevertheless raises several interesting mechanistic hypotheses and compelling opportunities for future research.

Controversies and reality of the FODMAP diet for patients with irritable bowel syndrome

Since its first trial showing evidence of efficacy for managing symptoms of irritable bowel syndrome, the fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet has been gaining popularity but not without criticism. Application of the diet has changed from a rigid list of "allowed" and "not allowed" foods to a structured program of initial FODMAP restriction followed by food reintroduction and finally personalization so that patients are empowered to adjust their diet themselves to achieve good predictability of symptoms. Safety concerns of the diet have centered around its initial elimination leading to compromise of nutritional and psychological health, but careful patient assessment and management, preferably through a FODMAP-trained dietitian, will reduce the risk of such negative health outcomes. Most negative attention for the FODMAP diet has been the notion that it will ruin the microbiota. Controlled studies have indicated that reducing FODMAP intake has no effects on bacterial diversity but will reduce total bacterial abundance, and higher FODMAP intakes will increase health-promoting bacteria, supporting the concept of the full FODMAP program, including attaining a minimal "maintenance" level of FODMAP restriction. This review addresses all these concerns in detail and how to overcome them, including the use of a "FODMAP-gentle" diet, describing restriction of a select few foods very concentrated in FODMAPs. This version of the diet is commonly applied in practice by experienced FODMAP-trained dietitians but is not clearly described in literature. Careful direction and assessment of response or nonresponse will decrease the risks of over-restriction and under-restriction of diet.

Randomised clinical trial: effect of low-FODMAP rye bread versus regular rye bread on the intestinal microbiota of irritable bowel syndrome patients: association with individual symptom variation

Background

A low intake of Fermentable, Oligo-, Di-, Mono-saccharides and Polyols (FODMAPs) is effective in the symptom control of irritable bowel syndrome (IBS) patients but may exert negative effects on the intestinal microbiota. The microbial effects of increasing regular or non-FODMAP fibre sources are largely unknown. Furthermore, it is not known if the baseline microbiota composition is associated with individual symptom control during the consumption of different rye products in IBS patients. Our objective was to evaluate whether increased consumption of low-FODMAP rye bread or regular rye bread for 4 weeks would alter the intestinal microbiota composition of IBS patients following their habitual diet, and whether these changes associate to symptoms and/or the baseline microbiota.

Methods

The study was conducted as a randomized double blind controlled cross-over study (n = 50). Microbiota was analysed by 16S rRNA gene sequencing and associated with gastrointestinal symptoms. Both microbial changes and their associations to symptoms were secondary outcomes.

Results

The consumption of the test breads did not alter microbiota diversity. Compared to baseline, consumption of the low FODMAP rye bread decreased the abundance of Bacteroides, Flavonifractor, Holdemania, Parasutterella and Klebsiella and showed a trend towards increased bifidobacteria, whereas the regular rye bread decreased the abundance of Flavonifractor. When comparing between the two test breads, Klebsiella was decreased after low-FODMAP rye bread intake. Patients whose symptoms decreased during the low-FODMAP rye bread displayed more Blautia and less Barnesiella at baseline.

Conclusions

Consumption of low-FODMAP rye bread had modest, potentially beneficial effects on patients’ microbiota while increasing their intake of fibre substantially. The baseline microbiota composition was associated with the variable degrees of symptom relief experienced by the patients. Consumption of a low-FODMAP rye bread might be one way to increase dietary fibre intake and improve the mild dysbiosis often observed among patients with IBS.

Trial registration

ClinicalTrials.gov: NCT02161120. Retrospectively registered 11 June 2014.

Electronic supplementary material

The online version of this article (10.1186/s40795-019-0278-7) contains supplementary material, which is available to authorized users.