Functional abdominal pain disorders (FAPDs) are pediatric gastrointestinal conditions marked by chronic or recurrent abdominal pain without anatomical and/or biochemical abnormalities. This position paper guides primary care providers in the early diagnosis and management of FAPDs to improve the well-being of affected children and their families.

A 12-member expert advisory board reviewed current approaches to diagnosing and managing FAPDs in children. Based on literature and discussions, 23 statements were drafted and voted on to achieve an acceptable level of agreement.

First-line healthcare professionals are key in diagnosing FAPDs, using ROME diagnostic criteria and recognizing red flags for accurate assessment and referrals. Comprehensive evaluation, including medical, dietary, and psychosocial history, physical exams, and basic tests helped to identify the initial triggers. Probiotics such as Limosilactobacillus (L. reuteri) DSM 17938 and Lacticaseibacillus rhamnosus (L. rhamnosus) help in alleviating functional abdominal pain (FAP) in children along with primary measures, such as dietary modifications [a balanced diet advocating moderation in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)-rich foods] and physical activity. Probiotics should be given for 6-8 weeks and can be resumed if symptoms recur. Cognitive-behavioral and hypnotic therapy also help, with remote options such as web-based, compact disk (CD)-based or application-based tools available.

This position paper provides expert insights to guide primary care providers in diagnosing and managing FAPDs, equipping them to make informed decisions for effective management of FAPDs.

Restricting dietary fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) can alleviate symptoms in children with disorders of gut-brain interaction (DGBI). Due to the restrictions of a low FODMAP diet (LFD), a less restrictive FODMAP Gentle diet (FGD) has been suggested. However, the types and amounts of high FODMAP foods and carbohydrates commonly consumed by children have not been studied. We aimed to identify the high FODMAP foods and proportions of FODMAP carbohydrates consumed by children with DGBI and healthy children (HC) and to determine which usually ingested FODMAPs would be restricted on the FGD.

Three-day diet records from both children with DGBI and HC were analyzed and compared to assess the type and amount of high FODMAP foods and carbohydrates ingested. Additionally, the ingested FODMAPs that would be restricted on the FGD were determined.

Diet records from 77 children with DGBI and 64 HC were analyzed. The number of foods ingested daily was similar between children with DGBI and HC (12.3 ± 4.2 vs 12.9 ± 3.4, respectively); high FODMAP foods comprised most foods eaten in both groups. Children with DGBI (vs. HC) ate fewer high FODMAP foods per day (6.5 ± 2.3 vs 8.7 ± 2.4, P < 0.0001, respectively). Fructans were the most consumed FODMAP carbohydrate in both groups, and children with DGBI (vs. HC) consumed fewer fructans, lactose, fructose, and polyols (all P < 0.0001). The top 3 food categories consumed in both groups were wheat-containing foods, dairy, and fruits/ 100% fruit juices. In children with DGBI, 80.9% of the high FODMAP foods consumed would be limited on the FGD.

Children with DGBI consume fewer high FODMAP foods and carbohydrates than HC, with the top consumed FODMAP carbohydrates being fructans, lactose, and fructose. A FGD would restrict most high FODMAP foods consumed by children with DGBI.

Background/Objectives: Disorders of gut-brain interaction (DGBI), characterized by chronic abdominal pain and significant disability, affect 15-20% of children and adults and continue into adulthood in ~60% of cases. Costs for adults reach USD 30 billion per year, yet effective management strategies are elusive. Studies support using cognitive behavioral therapy (CBT), but abdominal pain only improves in ~40% of patients. Dietary management (low FODMAP diet; LFD) has also shown promise but it is effective in only a similar percentage of patients. Studies suggest that biologic factors (biomarkers) contribute to CBT response. Similarly, gut microbiome composition appears to influence abdominal pain response to the LFD. However, no previous CBT trials in children or adults have measured these biomarkers, and it is unclear which patients respond best to CBT vs. LFD. Methods: Children aged 7-12 years with DGBIs (n = 200) will be categorized as having/not having Autonomic Nervous System imbalance and/or abnormalities in gut physiology. We will randomize these children to either CBT or a LFD to compare the effectiveness of these treatments in those with/without abnormal physiologic biomarkers. We hypothesize that CBT will be more effective in those without abnormal physiology and LFD will be more effective in children with abnormal physiology. Primary outcome measures include the following: (1) Symptom improvement (abdominal pain frequency/severity) and (2) improvement in health-related quality of life. Conclusions: This innovative multidisciplinary study is the first to identify physiological characteristics that may moderate the response to two different management strategies. Identification of these characteristics may reduce the burden of these disorders through timely application of the intervention most likely to benefit an individual patient.

Disorders of gut-brain interaction (DGBIs), including irritable bowel syndrome (IBS), are common among children. Although a diet that is low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) has been proven to help adults with IBS, there is conflicting evidence of its efficacy in pediatric patients.

This was a retrospective chart review of pediatric patients with DGBIs diagnosed by a pediatric gastroenterologist between December 2018 and April 2022 and referred to a dietician for low FODMAP diet (LFD). The diagnosis was based on Rome IV criteria, and the chart review was based on International Classification of Diseases 10 diagnosis codes for DGBIs. Subjective historical assessment was used to define symptom improvement. The causative FODMAP Monash group(s) were identified during the reintroduction phase based on a symptom diary.

A total of 58 patients were initially identified (38 females), 47 of whom completed the LFD and followed up. This included 24 patients with IBS-diarrhea predominant (IBS-D), 10 patients with IBS-mixed type (IBS-M), 6 patients with IBS-constipation predominant (IBS-C), and 7 patients with functional abdominal pain (FAP) or functional dyspepsia (FD). Symptom improvement occurred in 22 (91.6%) of IBS-D, 7 (70%) of IBS-M, 3 (50%) of IBS-C, and 3 (42.8%) of FAP/FD. Fructans, garlic, onions, and lactose were the most common offenders.

LFD improves symptoms in most patients with DGBIs, particularly those with IBS-D.

Our aim was to assess the use of a low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet in children with different types of functional abdominal pain disorders (FAPD) and to identify predictive factors of response to this diet.

This was a multicenter, experimental, uncontrolled, prospective trial. Patients with irritable bowel syndrome (IBS), functional dyspepsia, and functional abdominal pain followed a low FODMAP diet for 2 weeks. We collected data on abdominal pain before and after the diet. Patients who showed a ≥ 50 % reduction in abdominal pain frequency were considered responders.

A total of 48 patients with FAPD participated in this trial. They all showed a significant decrease in the frequency (p < 0.05) and intensity (p < 0.05) of abdominal pain after the diet. We considered 41.7 % of patients to be responders. Among children with functional dyspepsia, 66.6 % responded to the diet, and so did 71.4 % of those with IBS. On the contrary, 71.8 % of children with functional abdominal pain were non-responders, and this diagnosis was considered a predictive factor of poor response to the diet (OR: 9.87, CI [1.52; 63.97], p = 0.016).

In children with FAPD, a diagnosis of functional abdominal pain is a predictive factor of poor response to a low FODMAP diet. Better results were achieved with this diet in children with IBS or functional dyspepsia.

This systematic review and meta-analysis aimed to evaluate the effects of a low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet on gut microbiota regulation. A comprehensive literature search was conducted in PubMed, Cochrane Library, Web of Science, Embase, CNKI (China National Knowledge Infrastructure), and Wanfang Data databases. Randomized controlled trials (RCTs) comparing low FODMAP diets with normal diets were included. The primary outcome was the effect on intestinal flora. The standardized mean difference (SMD) with 95% confidence intervals (CI) was calculated using a random-effects model. Heterogeneity was assessed using the I2 statistic, and publication bias was evaluated using funnel plots and Egger's test. Ten RCTs involving 590 participants were included in the analysis. The low FODMAP diet showed a significant positive effect on intestinal flora compared to normal diets (SMD = 0.33, 95% CI [0.01, 0.64], p = 0.003). Substantial heterogeneity was observed (I2 = 67.5%). Subgroup analysis of irritable bowel syndrome (IBS) patients revealed no significant difference between low FODMAP and normal diets (SMD = 0.08, 95% CI [-0.17, 0.32], p = 0.306), with low heterogeneity (I2 = 17.0%). No significant publication bias was detected (Egger's test, p = 0.328). This meta-analysis suggests that a low FODMAP diet may have a positive effect on gut microbiota regulation. However, the effect appears to be less pronounced in IBS patients. Further high-quality studies are needed to confirm these findings and explore the long-term impact of low FODMAP diets on gut health across various gastrointestinal disorders.

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

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

EUCTR2015-003293-32-NL.

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

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

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder characterized by chronic abdominal pain, bloating, and altered bowel habits. Low-FODMAP diets, which involve restricting fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, have emerged as an effective dietary intervention for alleviating IBS symptoms. This review paper aims to synthesize current insights into the impact of a low-FODMAP diet on the gut microbiome and its mechanisms of action in managing IBS. We explore the alterations in microbial composition and function associated with a low-FODMAP diet and discuss the implications of these changes for gut health and symptom relief. Additionally, we examine the balance between symptom improvement and potential negative effects on microbial diversity and long-term gut health. Emerging evidence suggests that while a low-FODMAP diet can significantly reduce IBS symptoms, it may also lead to reductions in beneficial microbial populations. Strategies to mitigate these effects, such as the reintroduction phase and the use of probiotics, are evaluated. This review highlights the importance of a personalized approach to dietary management in IBS, considering individual variations in microbiome responses. Understanding the intricate relationship between diet, the gut microbiome, and IBS symptomatology will guide the development of more effective, sustainable dietary strategies for IBS patients.

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

Food allergies, particularly peanut (PN) allergies, are a growing concern, with fatal anaphylaxis incidents often reported. While palforzia is the sole FDA-approved drug for managing PN allergies, it is not universally effective.

This study aimed to investigate the potential of Gynostemma pentaphyllum saponins (GpS) as a novel therapeutic agent for PN allergy through modulation of gut microbiota, addressing the limitations of current treatments.

To elucidate the role of GpS on peanut allergy, we first built a PN-sensitized C57BL/6J model mice. Through comprehensive sequencing analysis, we identified Parabacteroides distasonis as a key bacterium triggering PN sensitization. Employing the same mouse model, GpS was evaluated for its effects on anaphylactic symptoms, serum immunoglobulin levels, and allergy-related biomarkers. 16S rRNA sequencing and transcriptomic analysis were applied to investigate the impact of GpS on the host's gut epithelium and microbiome.

GpS treatment effectively reduced anaphylactic symptoms in PN-sensitized mice, as shown by decreased IgG1, total IgE, and PN-specific IgE levels. It also modulated the immune response by suppressing proinflammatory cytokines (IL-1β, IFN-γ, IL-21) and chemokines (CCL5, CCL12, CCL17, CCL22), while enhancing anti-inflammatory cytokines (IL-4, IL-10, IL-12, IL-13). Fecal microbial transplant from GpS-treated Model mice to PN-sensitized mice displayed anti-peanut allergy effects. Additionally, the administration of GpS-enhanced bacteria (Clostridium aldenese or Lactobacillus murinus), alleviated anaphylactic symptoms and reduced serum allergy markers in PN-sensitized mice.

To conclude, we revealed the intestinal environment, signaling molecules, mucosal cytokines, and commensal microbial profiles in the peanut-sensitized mouse model. We further presented evidence for the protective effect of GpS against PN allergen sensitization by downregulating a series of food-allergy-associated biomarkers and cytokines via the modulation of gut bacteria. More importantly, supported by both in vitro and in vivo experiments, we demonstrated that the protective effect of GpS against PN-allergy is through the enhancement of two commensal bacteria, Clostridium aldenese, and Lactobacillus murinus.

Irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO) share similar abdominal symptoms; however, their differentiation remains controversial.

To illustrate the differences between the two conditions.

Patients and healthy controls completed questionnaires and provided stool samples for analysis.

IBS presented with the most severe symptoms and was specifically characterized by intense abdominal pain and frequent episodes of diarrhea. Patients with IBS displayed more dysregulated taxonomy within the fecal microbiota than SIBO. Opportunistic pathogens, including Lachnoclostridium, Escherichia-Shigella, and Enterobacter were enriched in the IBS group which contributed to increased bacterial pathogenicity and positively correlated with abdominal pain and bloating, meanwhile, Lachnoclostridium and Escherichia-Shigella were found to be associated with metabolites affiliated to bile acids, alcohols and derivatives. Bacteria enriched in SIBO group correlated with constipation. The bacterial co-occurrence network within the SIBO group was the most intricate. Ruminococcaceae Group were defined as core bacteria in SIBO. Differential metabolites affiliated to androstane steroids and phenylacetic acids were associated with core bacteria.

Our study elucidates the differences between IBS and SIBO in terms of symptoms, microbiota and functions, which provides insights into a better understanding of both diseases and evidence for different treatment strategies.

Endometriosis, affecting 10% of women in their reproductive years, remains poorly understood. Both individual and environmental unexplained factors are implicated in this heterogenous condition. This study aims to examine the influence of a Western diet on endometriosis lesion development in mice and to uncover the mechanisms involved.

Mice were fed either a control diet or a Western diet (high in fatty acids and low in fiber) for 4 weeks. Endometriosis was then surgically induced, and lesion development was monitored by ultrasound. After 7 weeks, the mice were sacrificed for analysis of lesion characteristics through RT-qPCR, immunohistochemistry, and flow cytometry. Additionally, the intestinal microbiota was assessed using 16S rRNA gene sequencing.

Mice on the Western diet developed lesions that were significantly twice as large compared to those on the control diet. These lesions exhibited greater fibrosis and proliferation, alongside enhanced macrophage activity and leptin pathway expression. Changes in the intestinal microbiota were significantly noted after endometriosis induction, regardless of diet. Notably, mice on the Western diet with the most substantial lesions showed a loss of Akkermansia Muciniphila in their intestinal microbiota.

A Western diet significantly exacerbates lesion size in a mouse model of endometriosis, accompanied by metabolic and immune alterations. The onset of endometriosis also leads to substantial shifts in intestinal microbiota, suggesting a potential link between diet, intestinal health, and endometriosis development.

In 1958, Apley and Naish authored a groundbreaking paper in Archives of Disease in Childhood, elucidating the epidemiology and risk factors of recurrent abdominal pain in children-a subject that had confounded clinicians of their time. Surprisingly, even after 65 years, there are several unanswered questions regarding the etiology, pathophysiology, and management of pediatric abdominal pain. Contrary to the prevailing notion that children naturally outgrow functional abdominal pain, compelling evidence suggests it's possible these children develop a number of clinically significant psychological issues that could profoundly impact their quality of life and, consequently, future health and educational outcomes. In this light, we aimed to comprehensively review the current literature to update the knowledge of practicing clinicians on functional abdominal pain, summarizing the evidence from the last 65 years.Conclusion: The enduring unanswered questions surrounding childhood abdominal pain continue to challenge clinicians, resulting in unnecessary investigations, thereby contributing to substantial healthcare expenditures. It is also evident that children with long-standing symptoms would progress to adulthood with the potential to develop irritable bowel syndrome and many psychological disturbances. Several key interventions using pharmacological agents, such as amitriptyline, showed that some of these drugs are no more effective than the placebo in clinical trials. Several research during the recent past suggest that psychological interventions such as gut-directed hypnotherapy alleviate symptoms and ensure better prognosis in the long run. Therefore, clinicians and researchers must join hands to explore the pathophysiological mechanisms underpinning functional abdominal pain and novel therapeutic strategies to ensure the well-being of these children. What is Known: • Functional abdominal pain disorders are common among children, with a worldwide prevalence of 13.5% of children suffering from at least one of these disorders • These disorders contribute to a significant reduction in the quality of life of affected children and their families and lead to an array of psychological problems What is New: • The biological basis of functional abdominal pain is becoming more explicit, including complex interactions between altered microbiome, deranged motility, and psychological dysfunction with gut-brain interactions • Novel approaches giving minimal emphasis on pharmacological interventions and exploring psychological interventions are showing promising results.

Irritable bowel syndrome (IBS) is a common and debilitating disorder manifesting with abdominal pain and bowel dysfunction. A mainstay of treatment is dietary modification, including restriction of FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). A greater response to a low FODMAP diet has been reported in those with a distinct IBS microbiome termed IBS-P. We investigated whether this is linked to specific changes in the metabolome in IBS-P.

Solid phase microextraction gas chromatography-mass spectrometry was used to examine the faecal headspace of 56 IBS cases (each paired with a non-IBS household control) at baseline, and after four-weeks of a low FODMAP diet (39 pairs). 50% cases had the IBS-P microbial subtype, while the others had a microbiome that more resembled healthy controls (termed IBS-H). Clinical response to restriction of FODMAPs was measured with the IBS-symptom severity scale, from which a pain sub score was calculated.

Two distinct metabotypes were identified and mapped onto the microbial subtypes. IBS-P was characterised by a fermentative metabolic profile rich in short chain fatty acids (SCFAs). After FODMAP restriction significant reductions in SCFAs were observed in IBS-P. SCFA levels did not change significantly in the IBS-H group. The magnitude of pain and overall symptom improvement were significantly greater in IBS-P compared to IBS-H (p = 0.016 and p = 0.026, respectively). Using just five metabolites, a biomarker model could predict microbial subtype with accuracy (AUROC 0.797, sensitivity 78.6% (95% CI: 0.78-0.94), specificity 71.4% (95% CI: 0.55-0.88).

A metabotype high in SCFAs can be manipulated by restricting fermentable carbohydrate, and is associated with an enhanced clinical response to this dietary restriction. This implies that SCFAs harbour pro-nociceptive potential when produced in a specific IBS niche. By ascertaining metabotype, microbial subtype can be predicted with accuracy. This could allow targeted FODMAP restriction in those seemingly primed to respond best.

This research was co-funded by Addenbrooke's Charitable Trust, Cambridge University Hospitals and the Wellcome Sanger Institute, and supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014).

This systematic review synthesizes findings from 12 studies to evaluate the effectiveness of dietary interventions in managing irritable bowel syndrome (IBS), with a focus on low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diets, probiotics, and prebiotics. The review rigorously follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and includes studies selected through comprehensive database searches. In adults diagnosed with IBS, this review assesses how effective dietary interventions, specifically low-FODMAP diets, probiotics, and prebiotics, are compared to standard management or placebo in improving clinical outcomes, modifying gut microbiota composition, and reducing inflammatory markers. Our analysis reveals that low-FODMAP diets consistently alleviate IBS symptoms and improve quality of life. However, the effectiveness of probiotics and prebiotics varies, with outcomes dependent on specific strains and individual patient microbiota profiles. The studies demonstrate significant improvements in gastrointestinal symptoms and microbiota composition, highlighting the potential of dietary strategies to beneficially modify gut health. However, the research points to the necessity of personalizing dietary approaches based on individual responses and microbiota profiles to optimize treatment efficacy. The risk of bias was assessed using the Cochrane risk-of-bias 2 tool for randomized controlled trials (RCTs) and the AMSTAR 2 tool for systematic reviews, with varying degrees of bias across the studies. This review identifies gaps in the long-term efficacy of these interventions and calls for more extensive trials to explore their sustained impacts. Our findings suggest that dietary management should be integrated into routine IBS treatment protocols and emphasize the need for further research to establish standardized dietary recommendations tailored to patient-specific characteristics.

In this article we present a protocol for the use of the low-FODMAP diet in paediatric patients and review of the current evidence on its efficacy. These short-chain carbohydrates, which can be fermented by the intestinal microbiota, are found in a wide variety of foods, mainly of plant origin. The low-FODMAP diet is a therapeutic tool used for the management of gastrointestinal disorders such as irritable bowel syndrome. The sources we used were PubMed, Web of Science, Google Scholar and institutional websites. Following consumption of FODMAP-rich foods, a series of end products are generated that are not absorbed, giving rise to symptoms. Before starting a low-FODMAP diet, it is important to carry out a diagnostic evaluation including any applicable tests. Treatment is structured in 3 phases: elimination, reintroduction and personalization phase. In the first phase, FODMAP-rich foods are eliminated for 2-3 weeks. In the second phase, lasting 8 weeks, FODMAP-rich foods are gradually reintroduced. The last phase consists in customizing the diet according to individual tolerance. This article details which foods contain FODMAPs and possible substitutes. In addition, specific food diary/intake tracking and educational materials are provided in a series of appendices to facilitate adherence to the diet. Although most studies have been conducted in adults, there is also some evidence on the beneficial effects in the paediatric age group, with a reduction of symptoms, especially in patients with functional gastrointestinal disorders. Nevertheless, more research is required on the subject.

The low-fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet (LFD) has been associated with reduced symptomology in pediatric functional gastrointestinal disorders (FGIDs). The LFD is a complex dietary intervention that may be difficult to follow; thus, there is great interest in determining factors that contribute to adherence.

To examine whether baseline abdominal pain, emotional/behavioral problems, or quality of life predict adherence to the LFD in children with FGIDs.

This was a single-group pre-post intervention design within a larger randomized controlled trial.

Thirty 7- to 12-year-old children with FGIDs were recruited from pediatric gastrointestinal and primary care settings throughout Texas from 2019 to 2021. Evaluated participants were randomized to an LFD intervention as part of a larger randomized controlled trial.

Participants received dietary counseling and followed the LFD for 3 weeks.

Emotional or behavioral problems and quality of life were obtained via parent report, and abdominal pain was measured via child report. Adherence was assessed by using diet records and computed by a decrease in consumption of overall FODMAP intake.

A hierarchical generalized linear mixed regression model examined factors associated with adherence.

Greater baseline quality of life was associated with better adherence to the LFD (beta coefficient β = -.02, P = 0.03), and baseline emotional/behavioral problems and abdominal pain complaints were not significantly associated with adherence (all Ps > 0.28).

Higher child quality of life as reported by parents was related to increased adherence to this complex dietary intervention.

According to national guidelines, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is a second-line therapy option for irritable bowel syndrome (IBS) and improves functional intestinal symptoms. Numerous noteworthy results have been published in this field over the past fifteen years. This study aims to analyze the global research trend and hotspot of the low FODMAP diet research, and provide a comprehensive perspective and direction for researchers.

The Science Citation Index-Expanded of the Web of Science Core Collection (WoSCC) was used to identify low FODMAP diet-related articles and reviews. Three bibliometric programs (CiteSpace, VOSviewer, Scimago Graphic) were utilized to analyze and visualize the annual publications, authors, countries, institutions, journals, citations, and keywords.

In total, 843 documents related to the low FODMAP diet research were published in 227 journals by 3,343 authors in 1,233 institutions from 59 countries. The United States, which was the most engaged nation in international collaboration, had the largest annual production and the fastest growth. The most productive organization was Monash University, and the most fruitful researcher was Gibson PR. Nutrients ranked first in terms of the number of published documents. The article "A diet low in FODMAPs reduces symptoms of irritable bowel syndrome" (Halmos EP, 2014) received the most co-citations. Keywords that appear frequently in the literature mainly involve two main aspects: the clinical efficacy evaluation and mechanism exploration of the low FODMAP diet. The term "gut microbiota" stands out as the most prominent keyword among the burst keywords that have remained prevalent till date.

The restriction stage of the low FODMAP diet is superior to other dietary therapies for IBS in terms of symptom response, but it has a negative impact on the abundance of gut Bifidobacteria and diet quality. Identification of biomarkers to predict response to the low FODMAP diet is of great interest and has become the current research hotspot.

The irritable bowel syndrome (IBS) is a functional gastrointestinal disorder (FGID), whose prevalence has widely increased in pediatric population during the past two decades. The exact pathophysiological mechanism underlying IBS is still uncertain, thus resulting in challenging diagnosis and management. Experts from 4 Italian Societies participated in a Delphi consensus, searching medical literature and voting process on 22 statements on both diagnosis and management of IBS in children. Recommendations and levels of evidence were evaluated according to the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was reached for all statements. These guidelines suggest a positive diagnostic strategy within a symptom-based approach, comprehensive of psychological comorbidities assessment, alarm signs and symptoms' exclusion, testing for celiac disease and, under specific circumstances, fecal calprotectin and C-reactive protein. Consensus also suggests to rule out constipation in case of therapeutic failure. Conversely, routine stool testing for enteric pathogens, testing for food allergy/intolerance or small intestinal bacterial overgrowth are not recommended. Colonoscopy is recommended only in patients with alarm features. Regarding treatment, the consensus strongly suggests a dietary approach, psychologically directed therapies and, in specific conditions, gut-brain neuromodulators, under specialist supervision. Conditional recommendation was provided for both probiotics and specific fibers supplementation. Polyethylene glycol achieved consensus recommendation for specific subtypes of IBS. Secretagogues and 5-HT4 agonists are not recommended in children with IBS-C. Certain complementary alternative therapies, antispasmodics and, in specific IBS subtypes, loperamide and rifaximin could be considered.

Abdominal pain remains one of the most common referral reasons to pediatric gastroenterology. Dietary intolerances are often considered but due to various factors are hardly pursued. We observed that diet review in large number of children with abdominal pain was high in sugary foods which led to food intolerance investigation and dietary intervention.

A retrospective review was conducted of patients presenting with abdominal pain, diarrhea, or vomiting and negative GI evaluation, who underwent fructose breath testing. Patients younger than 20 years old who were seen between June 1, 2018 and March 1, 2021 were included. Statistical analysis was performed in R.

There were 110 pediatric patients during the study period who underwent fructose breath testing, with 31% male and 69% female. The average age was 12.14 ± 4.01 years, and the average BMI was 21.21 ± 6.12. Abdominal pain was the most common presenting symptom (74.5%) followed by diarrhea and vomiting. Seventy-seven patients (70%) had a positive fructose breath test and were diagnosed with dietary intolerance to fructose. The 56 (67.5%) of those patients experienced symptoms during the breath test. Forty-three patients improved with dietary intervention. Twenty-seven on low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet and 16 on other diets.

Based on analysis of our cohort of children with abdominal pain and high incidence of fructose intolerance as well as improvement in symptoms, following dietary changes, this condition should be considered and treated. Further investigation is needed to improve diagnostic testing but also into understanding mechanisms behind symptom presentation in this population.

There is large variation in response to diet in irritable bowel syndrome (IBS) and determinants for differential response are poorly understood.

Our aim was to investigate differential clinical and molecular responses to provocation with fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) and gluten in individuals with IBS.

Data were used from a crossover study with week-long interventions with either FODMAPs, gluten or placebo. The study also included a rapid provocation test. Molecular data consisted of fecal microbiota, short chain fatty acids, and untargeted plasma metabolomics. IBS symptoms were evaluated with the IBS severity scoring system. IBS symptoms were modelled against molecular and baseline questionnaire data, using Random Forest (RF; regression and clustering), Parallel Factor Analysis (PARAFAC), and univariate methods.

Regression and classification RF models were in general of low predictive power (Q2 ≤ 0.22, classification rate < 0.73). Out of 864 clustering models, only 2 had significant associations to clusters (0.69 < CR < 0.73, p < 0.05), but with no associations to baseline clinical measures. Similarly, PARAFAC revealed no clear association between metabolome data and IBS symptoms.

Differential IBS responses to FODMAPs or gluten exposures could not be explained from clinical and molecular data despite extensive exploration with different data analytical approaches. The trial is registered at www.

gov as NCT03653689 31/08/2018.

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

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

The most frequent functional gastrointestinal disorders (FGID) in children include infantile colic, constipation, functional abdominal pain (FAP), and irritable bowel syndrome (IBS). Unfortunately, treatment options for FGID in children are limited, therefore many dietary interventions have been evaluated, including probiotics. This chapter summarizes currently available evidence and recommendations for probiotic use in the treatment of frequent FGIDs in children. The strongest evidence exists for the use of Limosilactobacillus (L.) reuteri DSM 17938 and Bifidobacterium animalis subsp. lactis BB-12 for the treatment of infantile colic in breastfed infants. Limited but yet encouraging evidence exists for Lacticaseibacillus rhamnosus GG (LGG) for the treatment of IBS and L. reuteri DSM 17938 for FAP.

Individuals with coeliac disease (CeD) often experience gastrointestinal symptoms despite adherence to a gluten-free diet (GFD). While we recently showed that a diet low in fermentable oligo-, di-, monosaccharides and polyols (FODMAP) successfully provided symptom relief in GFD-treated CeD patients, there have been concerns that the low FODMAP diet (LFD) could adversely affect the gut microbiota. Our main objective was therefore to investigate whether the LFD affects the faecal microbiota and related variables of gut health. In a randomised controlled trial GFD-treated CeD adults, having persistent gastrointestinal symptoms, were randomised to either consume a combined LFD and GFD (n 39) for 4 weeks or continue with GFD (controls, n 36). Compared with the control group, the LFD group displayed greater changes in the overall faecal microbiota profile (16S rRNA gene sequencing) from baseline to follow-up (within-subject β-diversity, P < 0·001), characterised by lower and higher follow-up abundances (%) of genus Anaerostipes (Pgroup < 0·001) and class Erysipelotrichia (Pgroup = 0·02), respectively. Compared with the control group, the LFD led to lower follow-up concentrations of faecal propionic and valeric acid (GC-FID) in participants with high concentrations at baseline (Pinteraction ≤ 0·009). No differences were found in faecal bacterial α-diversity (Pgroup ≥ 0·20) or in faecal neutrophil gelatinase-associated lipocalin (ELISA), a biomarker of gut integrity and inflammation (Pgroup = 0·74), between the groups at follow-up. The modest effects of the LFD on the gut microbiota and related variables in the CeD patients of the present study are encouraging given the beneficial effects of the LFD strategy to treat functional GI symptoms (Registered at clinicaltrials.gov as NCT03678935).

The gut microbiota is believed to be a critical factor in the pathogenesis of IBS, and its metabolic byproducts, such as short-chain fatty acids (SCFAs), are known to influence gut function and host health. Despite this, the precise role of SCFAs in IBS remains a topic of debate. In this study, we examined the bacterial community structure by 16S rRNA gene profiling and SCFA levels by UPLC-MS/MS in fecal samples from healthy controls (HC; n = 100) and non-constipated patients (IBS-D and IBS-M; NC-IBS; n = 240) enrolled in 19 hospitals in Italy. Our findings suggest a significant difference between the fecal microbiomes of NC-IBS patients and HC subjects, with HC exhibiting higher intra-sample biodiversity. Furthermore, we were able to classify non-constipated patients into two distinct subgroups based on their fecal SCFA levels (fecal catabotype "high" and "low"), each characterized by unique taxonomic bacterial signatures. Our results suggest that the fecal catabotype with higher SCFA levels may represent a distinct clinical phenotype of IBS that could have implications for its diagnosis and treatment. This study provides a new perspective on the intricate relationship between the gut microbiome and bowel symptoms in IBS, underscoring the importance of personalized strategies for its management.

An increase in postprandial intestinal gas plays a role in bloating symptoms. We aim to study the utility of spot breath hydrogen (H2) level in predicting the response to a low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet.

Patients with functional gastrointestinal disorders diagnosed by Rome IV criteria with bothersome bloating for > 6 months were prospectively enrolled. Patients completed 7-day food diaries and collected a breath sample 2 hours after their usual lunch at baseline and 4 weeks after low FODMAPs dietary advice by a dietitian. The responder was defined as an improvement of ≥ 30% bloating scores in the fourth week.

Thirty-eight patients (32 female, 52.6 ± 13.8 years; 22 irritable bowel syndrome) completed the study. Twenty-one patients (55%) were classified as responders. Baseline global gastrointestinal symptoms, bloating, abdominal pain scores, and numbers of high FODMAPs items were similar between responders and non-responders. Both groups significantly decreased high FODMAPs items intake with similar numbers at the follow-up. The area under the curve for predicting low FODMAPs responsiveness using baseline H2 levels was 0.692 (95%CI, 0.51-0.86; P < 0.05), with the best cutoff at 8 parts per million (sensitivity 66.7%, specificity 82.4%). 66% of responders had baseline H2 level > 8 parts per million vs 17% of non-responders (P < 0.05). The baseline spot hydrogen level in responders was 9.5 (3.3-17.3) vs 4.5 (3.3-6.3) in non-responders (P < 0.05).

A higher baseline breath hydrogen level was associated with bloating improvement after low FODMAPs dietary advice. A spot breath test after lunch, a simple point-of-care test, is possibly helpful in managing patients with bloating.

The composition, viability and metabolic functionality of intestinal microbiota play an important role in human health and disease. Studies on intestinal microbiota are often based on fecal samples, because these can be sampled in a non-invasive way, although procedures for sampling, processing and storage vary. This review presents factors to consider when developing an automated protocol for sampling, processing and storing fecal samples: donor inclusion criteria, urine-feces separation in smart toilets, homogenization, aliquoting, usage or type of buffer to dissolve and store fecal material, temperature and time for processing and storage and quality control. The lack of standardization and low-throughput of state-of-the-art fecal collection procedures promote a more automated protocol. Based on this review, an automated protocol is proposed. Fecal samples should be collected and immediately processed under anaerobic conditions at either room temperature (RT) for a maximum of 4 h or at 4 °C for no more than 24 h. Upon homogenization, preferably in the absence of added solvent to allow addition of a buffer of choice at a later stage, aliquots obtained should be stored at either -20 °C for up to a few months or -80 °C for a longer period-up to 2 years. Protocols for quality control should characterize microbial composition and viability as well as metabolic functionality.

Endometriosis and irritable bowel syndrome (IBS) are chronic conditions affecting up to 10% of the global population, imposing significant burdens on healthcare systems and patient quality of life. Interestingly, around 20% of endometriosis patients also present with symptoms indicative of IBS. The pathogenesis of both these multifactorial conditions remains to be fully elucidated, but connections to gut microbiota are becoming more apparent. Emerging research underscores significant differences in the gut microbiota composition between healthy individuals and those suffering from either endometriosis or IBS. Intestinal dysbiosis appears pivotal in both conditions, exerting an influence via similar mechanisms. It impacts intestinal permeability, triggers inflammatory reactions, and initiates immune responses. Furthermore, it is entwined in a bidirectional relationship with the brain, as part of the gut-brain axis, whereby dysbiosis influences and is influenced by mental health and pain perception. Recent years have witnessed the development of microbiota-focused therapies, such as low FODMAP diets, prebiotics, probiotics, antibiotics, and fecal microbiota transplantation, designed to tackle dysbiosis and relieve symptoms. While promising, these treatments present inconsistent data, highlighting the need for further research. This review explores the evidence of gut dysbiosis in IBS and endometriosis, underscoring the similar role of microbiota in both conditions. A deeper understanding of this common mechanism may enable enhanced diagnostics and therapeutic advancements.

A growing body of evidence suggests that the gut microbiota is strongly linked to general human health. Microbiome-directed interventions, such as diet and exercise, are acknowledged as a viable and achievable strategy for preventing disorders and improving human health. However, due to the significant inter-individual diversity of the gut microbiota between subjects, lifestyle recommendations are expected to have distinct and highly variable impacts to the microbiome structure.

Here, through a large-scale meta-analysis including 1448 shotgun metagenomics samples obtained longitudinally from 396 individuals during lifestyle studies, we revealed Bacteroides stercoris, Prevotella copri, and Bacteroides vulgatus as biomarkers of microbiota's resistance to structural changes, and aromatic and non-aromatic amino acid biosynthesis as important regulator of microbiome dynamics. We established criteria for distinguishing between significant compositional changes from normal microbiota fluctuation and classified individuals based on their level of response. We further developed a machine learning model for predicting "responders" and "non-responders" independently of the type of intervention with an area under the curve of up to 0.86 in external validation cohorts of different ethnicities.

We propose here that microbiome-based stratification is possible for identifying individuals with highly plastic or highly resistant microbial structures. Identifying subjects that will not respond to generalized lifestyle therapeutic interventions targeting the restructuring of gut microbiota is important to ensure that primary end-points of clinical studies are reached. Video Abstract.

High rates of overlap exist between disorders of gut-brain interaction (DGBI) and eating disorders, for which common interventions conceptually conflict. There is particularly increasing recognition of eating disorders not centered on shape/weight concerns, specifically avoidant/restrictive food intake disorder (ARFID) in gastroenterology treatment settings. The significant comorbidity between DGBI and ARFID highlights its importance, with 13% to 40% of DGBI patients meeting full criteria for or having clinically significant symptoms of ARFID. Notably, exclusion diets may put some patients at risk for developing ARFID and continued food avoidance may perpetuate preexisting ARFID symptoms. In this review, we introduce the provider and researcher to ARFID and describe the possible risk and maintenance pathways between ARFID and DGBI. As DGBI treatment recommendations may put some patients at risk for developing ARFID, we offer recommendations for practical treatment management including evidence-based diet treatments, treatment risk counseling, and routine diet monitoring. When implemented thoughtfully, DGBI and ARFID treatments can be complementary rather than conflicting.

The low FODMAP diet (LFD) leads to clinical response in 50%-80% of patients with irritable bowel syndrome (IBS). It is unclear why only some patients respond.

To determine if differences in baseline faecal microbiota or faecal and urine metabolite profiles may separate clinical responders to the diet from non-responders allowing predictive algorithms to be proposed.

We recruited adults fulfilling Rome III criteria for IBS to a blinded randomised controlled trial. Patients were randomised to sham diet with a placebo supplement (control) or LFD supplemented with either placebo (LFD) or 1.8 g/d B-galactooligosaccharide (LFD/B-GOS), for 4 weeks. Clinical response was defined as adequate symptom relief at 4 weeks after the intervention (global symptom question). Differences between responders and non-responders in faecal microbiota (FISH, 16S rRNA sequencing) and faecal (gas-liquid chromatography, gas-chromatography mass-spectrometry) and urine (1 H NMR) metabolites were analysed.

At 4 weeks, clinical response differed across the 3groups with adequate symptom relief of 30% (7/23) in controls, 50% (11/22) in the LFD group and 67% (16/24) in the LFD/B-GOS group (p = 0.048). In the control and the LFD/B-GOS groups, microbiota and metabolites did not separate responders from non-responders. In the LFD group, higher baseline faecal propionate (sensitivity 91%, specificity 89%) and cyclohexanecarboxylic acid esters (sensitivity 80%, specificity 78%), and urine metabolite profile (Q2 0.296 vs. randomised -0.175) predicted clinical response.

Baseline faecal and urine metabolites may predict response to the LFD.

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal (GI) disorders in the world. Although IBS does not affect a person's life span, it can significantly influence their quality of life. The treatment of IBS should be tailored to each patient's specific symptomatology because it can often be difficult to manage. Given that the pathogenesis of IBS is not well understood, it places a tremendous load on healthcare resources. Over the years, IBS has been described as either a simple GI disorder or a more complex multi-symptomatic gut-brain axis disorder. Many persons with IBS have psychological issues in addition to gastrointestinal symptoms, offering the door to non-pharmacological therapies such as cognitive behavioral therapy, gut-directed hypnosis, or psychodynamic interpersonal therapy. Non-pharmacological therapies with no side effects should be used as first-line therapy. Diet, exercise, microbiota-targeted therapies, and psychological treatments are among the most significant interventions. This review goes into the details of all the non-pharmacological interventions that can be used to treat IBS.

In humans, many diseases are associated with alterations in gut microbiota, namely increases or decreases in the abundance of specific bacterial groups. One example is the genus Faecalibacterium. Numerous studies have underscored that low levels of Faecalibacterium are correlated with inflammatory conditions, with inflammatory bowel disease (IBD) in the forefront. Its representation is also diminished in the case of several diseases, including colorectal cancer (CRC), dermatitis, and depression. Additionally, the relative presence of this genus is considered to reflect, at least in part, intestinal health status because Faecalibacterium is frequently present at reduced levels in individuals with gastrointestinal diseases or disorders. In this review, we first thoroughly describe updates to the taxonomy of Faecalibacterium, which has transformed a single-species taxon to a multispecies taxon over the last decade. We then explore the links discovered between Faecalibacterium abundance and various diseases since the first IBD-focused studies were published. Next, we examine current available strategies for modulating Faecalibacterium levels in the gut. Finally, we summarize the mechanisms underlying the beneficial effects that have been attributed to this genus. Together, epidemiological and experimental data strongly support the use of Faecalibacterium as a next-generation probiotic (NGP) or live biotherapeutic product (LBP).

Irritable bowel syndrome (IBS), a disorder of the gut-brain axis, is affected by the microbiome. Microbial studies in pediatric IBS, especially for centrally mediated treatments, are lacking. We compared the microbiome between pediatric IBS patients and healthy controls (HC), in relation to symptom severity, and with percutaneous electrical nerve field stimulation (PENFS), a non-invasive treatment targeting central pain pathways.

We collected a stool sample, questionnaires and a 1-2 week stool and pain diary from 11 to 18 years patients with IBS. A patient subset completed 4 weeks of PENFS and repeated data collection immediately after and/or 3 months after treatment. Stool samples were collected from HC. Samples underwent metagenomic sequencing to evaluate diversity, composition, and abundance of species and MetaCyc pathways.

We included 27 cases (15.4 ± 2.5 year) and 34 HC (14.2 ± 2.9 year). Twelve species including Firmicutes spp., and carbohydrate degradation/long-chain fatty acid (LCFA) synthesis pathways, were increased in IBS but not statistically significantly associated with symptom severity. Seventeen participants (female) who completed PENFS showed improvements in pain (p = 0.012), disability (p = 0.007), and catastrophizing (p = 0.003). Carbohydrate degradation and LCFA synthesis pathways decreased post-treatment and at follow-up (FDR p-value <0.1).

Firmicutes, including Clostridiaceae spp., and LCFA synthesis pathways were increased in IBS patients suggesting pain-potentiating effects. PENFS led to marked improvements in abdominal pain, functioning, and catastrophizing, while Clostridial species and LCFA microbial pathways decreased with treatment, suggesting these as potential targets for IBS centrally mediated treatments.

Functional abdominal pain disorders (FAPDs) affect up to 25% of children in the United States. These disorders are more recently known as disorders of "brain-gut" interaction. The diagnosis is based on the ROME IV criteria, and requires the absence of an organic condition to explain the symptoms. Although these disorders are not completely understood, several factors have been involved in the pathophysiology including disordered gut motility, visceral hypersensitivity, allergies, anxiety/stress, gastrointestinal infection/inflammation, as well dysbiosis of the gut microbiome. The pharmacologic and non-pharmacologic treatments for FAPDs are directed to modifying these pathophysiologic mechanisms. This review aims to summarize the non-pharmacologic interventions used in the treatment of FAPDs including dietary modifications, manipulation of the gut microbiome (neutraceuticals, prebiotics, probiotics, synbiotics and fecal microbiota transplant) and psychological interventions that addresses the "brain" component of the brain-gut axis (cognitive behavioral therapy, hypnotherapy, breathing and relaxation techniques). In a survey conducted at a large academic pediatric gastroenterology center, 96% of patients with functional pain disorders reported using at least 1 complementary and alternative medicine treatment to ameliorate symptoms. The paucity of data supporting most of the therapies discussed in this review underscores the need for large randomized controlled trials to assess their efficacy and superiority compared to other treatments.

Functional gastrointestinal disorders (FGIDs) are common in children and adolescents. In recent years, interest in the role of diet in the treatment of FGIDs has increased. Currently, interest focuses on the low-FODMAP diet (LFD), the fructose- or lactose-restricted diet (FRD or LRD), the gluten-free diet (GFD), and the Mediterranean diet (MD). In this review, we focus on the role of these dietary patterns in the FGIDs most commonly diagnosed in clinical practice, namely irritable bowel syndrome (IBS), functional abdominal pain (FAP), functional dyspepsia (FD), and functional constipation (FC). Fifteen clinical trials were systematically reviewed (both RCTs and single-arm clinical trials). We demonstrated the lack of high-quality intervention trials. Based on current evidence, low-FODMAP diet, LRD, FRD, and GFD have no place in daily clinical practice for the management of children and adolescents with FGIDs. Nevertheless, some patients with IBS or RAP may experience some benefit from the use of a low-FODMAP diet or FRD/LRD. Limited data suggest that MD may be promising in the management of FGIDs, especially in IBS patients, but more data are required to investigate the mechanisms of its protective effects.

Dietary therapies are recommended for the treatment of pediatrics with functional abdominal pain disorders (FAPDs), but the comparative effectiveness among them is unclear. Therefore, the main aim of this systematic review and meta-analysis was to compare the effectiveness of differential dietary therapies in pediatrics with functional abdominal pain disorders. We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases from inception to February 28, 2023. Randomized clinical trials of dietary treatments for pediatric patients with functional abdominal pain disorders were included. The primary outcome was the improvement in abdominal pain. The secondary outcomes were changes in pain intensity and pain frequency. Thirty-one studies after screening 8695 retrieved articles were included, and 29 studies were available for network meta-analysis. Compared with placebo, fiber (RR, 4.86; 95%CI, 1.77 to 13.32; P-score = 0.84), synbiotics (RR, 3.92; 95%CI, 1.65 to 9.28; P-score = 0.75), and probiotics (RR, 2.18; 95%CI, 1.46 to 3.26; P-score = 0.46) had significantly larger effect on the improvement in abdominal pain, the three treatments had larger effect than placebo but statistically insignificant in difference in improving pain frequency and intensity. Similarly, there were no significant differences between the dietary treatments after indirect comparisons of the three outcomes.  Conclusion: Fiber supplements, synbiotics, and probiotics were efficacious in improving abdominal pain of FAPDs in children, suggested by very low or low evidence. The evidence of the efficacy of probiotics is more convincing than fiber and synbiotics when sample size and statistical power were considered. No difference in the efficacy of the three treatments. High-quality trials are needed to further investigate the efficacy of dietary interventions. What is Known: • Multiple dietary treatment options are available for functional abdominal pain disorders in the pediatric population, of which the most beneficial one is currently unknown. What is New: • This NMA found very low to low certainty of the evidence suggesting that fiber, synbiotics, and probiotics might be more efficacious in improving abdominal pain of FAPDs in children than the other dietary treatments. • There were no significant differences between active dietary treatments for changes in abdominal pain intensity.