Non-Celiac Gluten Sensitivity in the Context of Functional Gastrointestinal Disorders

Effects of Gluten on Gut Microbiota in Patients with Gastrointestinal Disorders, Migraine, and Dermatitis

As gluten may trigger gastrointestinal disorders (GIDs), its presence or absence in the diet can change the diversity and proportion of gut microbiota. The effects of gluten after six weeks of a double-blind, placebo-controlled intervention with a gluten-free diet (GFD) were studied in participants with GIDs suffering from migraines and atopic dermatitis (n = 46). Clinical biomarkers, digestive symptoms, stool, the Migraine Disability Assessment questionnaire, and zonulin levels were analyzed. Next-generation sequencing was used to amplify the 16S rRNA gene of bacteria and the internal transcribed spacer (ITS) regions of fungi. The GFD increased Chao1 fungal diversity after the intervention, while the fungal composition showed no changes. Bacterial diversity and composition remained stable, but a positive association between bacterial and fungal Chao1 diversity and a negative association between Dothideomycetes and Akkermansia were observed. GIDs decreased in both groups and migraines improved in the placebo group. Our findings may aid the development of GID treatment strategies.

Nonallergic Diseases Associated With Foods

Clinicians are faced with evaluating real and alleged reactions to foods that may be allergic or nonallergic. Pathogenesis, diagnosis, and treatment of various non-IgE-mediated diseases are discussed in this review. These food-related conditions range from mild to severe. Referral for an allergy workup may be pursued despite the lack of IgE-mediated symptoms. Diagnostic testing is available for defined non-IgE-mediated food diseases that are either immunologic or nonimmunologic. These include celiac disease and related disorders, carbohydrate maldigestion, pancreatic insufficiency, and histamine intolerance. In contrast, there is a paucity of definitive studies to prove food intolerance diseases. There are no definitive diagnostic criteria or testing for nonceliac gluten sensitivity. Functional gastrointestinal disorders, such as irritable bowel syndrome, are better stratified diagnostically but still lack reliable testing. Both nonceliac gluten sensitivity and irritable bowel syndrome are linked to dietary triggers including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Therefore, dietary alteration alone may be diagnostic and therapeutic when all other conditions are ruled out. These conditions are important considerations when evaluating a patient with history of a food reaction. There is little evidence that foods are causative in other ailments such as acne, migraines, and nasal congestion and hypersecretion.

The effect of expectancy versus actual gluten intake on gastrointestinal and extra-intestinal symptoms in non-coeliac gluten sensitivity: a randomised, double-blind, placebo-controlled, international, multicentre study

BACKGROUND

Many individuals without coeliac disease or wheat allergy reduce their gluten intake because they believe that gluten causes their gastrointestinal symptoms. Symptoms could be affected by negative expectancy. Therefore, we aimed to investigate the effects of expectancy versus actual gluten intake on symptoms in people with non-coeliac gluten sensitivity (NCGS).

METHODS

This randomised, double-blind, placebo-controlled, international, multicentre study was done at the University of Leeds (Leeds, UK), Maastricht University (Maastricht, the Netherlands), and Wageningen University and Research (Wageningen, the Netherlands). People aged 18-70 years with self-reported NCGS (ie, gastrointestinal symptoms within 8 h of gluten consumption) without coeliac disease and wheat allergy were recruited. Participants had to follow a gluten-free or gluten-restricted diet for at least 1 week before (and throughout) study participation and had to be asymptomatic or mildly symptomatic (overall gastrointestinal symptom score ≤30 mm on the Visual Analogue Scale [VAS]) while on the diet. Participants were randomly assigned (1:1:1:1; blocks of eight; stratified by site and gender) to one of four groups based on the expectation to consume gluten-containing (E+) or gluten-free (E-) oat bread for breakfast and lunch (two slices each) and actual intake of gluten-containing (G+) or gluten-free (G-) oat bread. Participants, investigators, and those assessing outcomes were masked to the actual gluten assignment, and participants were also masked to the expectancy part of the study. The primary outcome was overall gastrointestinal symptom score on the VAS, which was measured at and corrected for baseline (before breakfast) and hourly for 8 h, with lunch served after 4 h, and analysed per-protocol. Safety analysis included all participants incorporated in the per-protocol analysis. The study is registered at ClinicalTrials.gov, NCT05779358, and has ended.

FINDINGS

Between Oct 19, 2018, and Feb 14, 2022, 165 people were screened and 84 were randomly assigned to E+G+ (n=21), E+G- (n=21), E-G+ (n=20), or E-G- (n=22). One person in the E+G+ group was excluded due to not following test day instructions, leaving 83 participants in the per-protocol analysis. Median age was 27·0 years (IQR 21·0-45·0), 71 (86%) of 83 people were women, and 12 (14%) were men. Mean overall gastrointestinal symptom score was significantly higher for E+G+ (16·6 mm [95% CI 13·1 to 20·0]) than for E-G+ (6·9 mm [3·5 to 10·4]; difference 9·6 mm [95% CI 3·0 to 16·2], p=0·0010) and E-G- (7·4 mm [4·2 to 10·7]; difference 9·1 mm [2·7 to 15·6], p=0·0016), but not for E+G- (11·7 mm [8·3 to 15·1]; difference 4·9 mm [-1·7 to 11·5], p=0·28). There was no difference between E+G- and E-G+ (difference 4·7 mm [-1·8 to 11·3], p=0·33), E+G- and E-G- (difference 4·2 mm [-2·2 to 10·7], p=0·47), and E-G+ and E-G- (difference -0·5 mm [-7·0 to 5·9], p=1·0). Adverse events were reported by two participants in the E+G- group (itching jaw [n=1]; feeling lightheaded and stomach rumbling [n=1]) and one participant in the E-G+ group (vomiting).

INTERPRETATION

The combination of expectancy and actual gluten intake had the largest effect on gastrointestinal symptoms, reflecting a nocebo effect, although an additional effect of gluten cannot be ruled out. Our results necessitate further research into the possible involvement of the gut-brain interaction in NCGS.

FUNDING

Government of the Netherlands Topsector Agri & Food Top Consortium for Knowledge and Innovation, AB Mauri Global Bakery Ingredients, Baking Industry Research Trust, Borgesius-Albert Heijn, CSM Innovation Centre, the International Maize and Wheat Improvement Center (CIMMYT), DSM Food Specialties, Fazer, Healthgrain Forum, the International Association for Cereal Science and Technology, the International Wheat Gluten Association, Lantmännen, Mondelez International, Nederlands Bakkerij Centrum, Nutrition & Santé, Puratos, Rademaker, Sonneveld Group, and Zeelandia HJ Doeleman.

Effects of gluten on dyspeptic symptoms: a systematic review and meta-analysis of clinical trials

CONTEXT

Research on the effects of gluten on dyspeptic symptoms has shown conflicting results.

OBJECTIVE

The aim of this systematic review and meta-analysis of clinical trials was to assess the effects of gluten on dyspeptic symptoms.

DATA SOURCES

A systematic search of the PubMed, ISI Web of Science, Scopus, Cochrane, and Embase online databases was performed up to May 2022.

DATA EXTRACTION

Randomized controlled trials (RCTs) and non-RCTs that examined the impact of a gluten-free diet, a low-gluten diet, or a gluten challenge on dyspeptic symptoms, including early satiety, epigastric pain, bloating, and nausea, were selected independently by 2 authors. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework was used to assess the certainty of the evidence. Results were pooled using a random-effects model and expressed as weighted mean differences (WMDs) and 95%CIs.

DATA ANALYSIS

Of the 7641 citations retrieved, 27 articles (18 RCTs and 9 non-RCTs) were included in the systematic review. Of those, 5 RCTs were eligible for the meta-analysis. The pooled results indicated that gluten challenge significantly increased the severity of bloating (WMD = 0.67; 95%CI, 0.37-0.97; I2 = 81.8%; n = 6), early satiety (WMD = 0.91; 95%CI, 0.58-1.23; I2 = 27.2%; n = 5), and epigastric pain (WMD = 0.46; 95%CI, 0.17-0.75; I2 = 65.8%; n = 6). However, the effect of gluten challenge on the severity of nausea (WMD = 0.13; 95%CI, -0.17 to 0.43; I2 = 0.0%, n = 5) was nonsignificant.

CONCLUSION

Gluten challenge significantly worsened dyspeptic symptoms, including bloating, early satiety, and epigastric pain, but did not affect nausea. These findings suggest that gluten restriction could be efficient in reducing dyspeptic symptoms. Well-designed large RCTs recruiting homogenous groups of patients with functional dyspepsia are needed to clarify the effectiveness of gluten restriction on dyspeptic symptoms.

A personalized management approach in disorders of the irritable bowel syndrome spectrum

Symptoms of the disorders across the irritable bowel syndrome (IBS) spectrum include several different, usually postprandial, abdominal complaints. Up to date, dietary treatments of the IBS have neither been personalized nor diagnosed with sufficient scientific evidence. They have mostly been treated using 'one-size-fits-all' approaches. Such include exclusion diets, a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet, and gluten-free diets, lactose-free diets, a diet recommended by the UK National Institute for Health and Care Excellence, and a wheat-free diet. The exact pathophysiology of IBS disorders across the spectrum is still unclear. However, the symptom profile of IBS spectrum disorders seems similar to that of food intolerance/malabsorption syndromes. Celiac disease, fructose malabsorption, histamine intolerance and lactose intolerance represent food intolerance/malabsorption disorders based on the indigestion of sugars and/or proteins. Helicobacter pylori infection may potentially promote the development of IBS and, when facing a case of IBS-like symptoms, a search for intolerance/malabsorption and H. pylori should be added to find the correct treatment for the respective patient. This review will discuss why the 'one-size-fits-all' dietary approach in the treatment of complaints across the IBS spectrum cannot be successful. Hence, it will provide an overview of the most common overall dietary approaches currently used, and why those should be discouraged. Alternatively, a noninvasive diagnostic workup of the pathophysiologic factors of food intolerance/malabsorption in each patient with symptoms of the IBS spectrum is suggested. Additionally, if H. pylori is found, eradication therapy is mandatory, and if food intolerance/malabsorption is detected, an individual and personalized dietary intervention by a registered dietician is recommended.

Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) are an extremely common set of more than 50 disorders characterized by persistent and recurring gastrointestinal symptoms. Most of these patients can be diagnosed and managed by primary care physicians. Treatment includes patient education and reassurance, eliminating triggers, dietary modification, and pharmacologic management. Primary care physicians should consider referral to gastroenterologists when patients exhibit red flag symptoms such as blood in stool, abnormal laboratory findings, involuntary weight loss, age of presentation greater than 50 years, or certain concerning family history.

High frequency of gastrointestinal complaints, but insignificant prevalence of gluten-sensitive enteropathies in Brazilian fibromyalgia patients

INTRODUCTION/OBJECTIVES

Coeliac disease (CD) and non-coeliac gluten sensitivity (NCGS) cause symptoms like those seen in patients with fibromyalgia (FM) and functional gastrointestinal disorders. There is no consistent data on frequency of these symptoms and no study performed duodenal biopsies to investigate CD/NCGS in Brazilian FM patients. Therefore, we sought to verify the prevalence of CD/NCGS in FM patients and the association between gastrointestinal manifestations and FM symptoms.

MATERIAL AND METHODS

Sixty-two individuals with FM (ACR2010) were recruited from FM outpatient clinics of a tertiary hospital. Clinical evaluation included the Widespread Pain Index (WPI), Severity Symptom Scale (SS), Polysymptomatic Distress Scale (PDS), and Fibromyalgia Impact Questionnaire (FIQ). Subjects were screened for the presence of coeliac antibodies and upper gastrointestinal endoscopy (duodenal biopsies) was performed for diagnosis of CD/NCGS.

RESULTS

46 (74.2%) women reported at least one digestive symptom: constipation, abdominal distension, loss of weight/inappetence, and nausea/vomiting. Fourteen (31.8%) presented macroscopic duodenitis and 2(4.5%) had duodenal lymphocytic infiltrates, but none met CD criteria. In 1(1.6%) patient NCGS was confirmed. There was association between presence of any digestive symptom and WPI and SS (fatigue, waking up tired, cognition), but no difference on FIQ between patients with and without gastrointestinal symptoms.

CONCLUSION

Gastrointestinal complaints were frequent and associated with increased degree of polysymptomatic distress in FM patients, but presence of these symptoms was not related to overall impact of FM over different dimensions of the patient's life. Moreover, the prevalence of CD/NCGS was very low. This suggests that screening for CD in Brazilian FM patients might not be cost-effective, since the frequency of CD/NCGS was very low.

Allergenicity of wheat protein in diet: Mechanisms, modifications and challenges

Wheat is widely available in people's daily diets. However, some people are currently experiencing IgE-mediated allergic reactions to wheat-based foods, which seriously impact their quality of life. Thus, it is imperative to provide comprehensive knowledge and effective methods to reduce the risk of wheat allergy (WA) in food. In the present review, recent advances in WA symptoms, the major allergens, detection methods, opportunities and challenges in establishing animal models of WA are summarized and discussed. Furthermore, an updated overview of the different modification methods that are currently being applied to wheat-based foods is provided. This study concludes that future approaches to food allergen detection will focus on combining multiple tools to rapidly and accurately quantify individual allergens in complex food matrices. Besides, biological modification has many advantages over physical or chemical modification methods in the development of hypoallergenic wheat products, such as enzymatic hydrolysis and fermentation. It is worth noting that using biotechnology to edit wheat allergen genes to produce allergen-free food may be a promising method in the future which could improve the safety of wheat foods and the health of allergy sufferers.

Efficacy of Different Dietary Patterns in the Treatment of Functional Gastrointestinal Disorders in Children and Adolescents: A Systematic Review of Intervention Studies

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.

Bacillus licheniformis reverses the environmental ceftriaxone sodium-induced gut microbial dysbiosis and intestinal inflammation in mice

Antibiotics used as a common clinical treatment have saved many lives. Widespread use of antibiotic therapy has been known to disrupt the balance of pathogenic bacteria, host-associated microorganisms and environment. However, our understanding of Bacillus licheniformis for health benefits and ability to restore the ceftriaxone sodium-induced gut microbial dysbiosis is severely limited. We used Caco-2 cell, H&E (hematoxylin-eosin staining), RT-PCR and 16S rRNA sequencing techniques to investigate the influence of Bacillus licheniformis on gut microbial dysbiosis and inflammation following ceftriaxone sodium treatment. The results showed that treatment of ceftriaxone sodium in 7 days suppressed the expression of Nf-κB pathway mRNA levels, which caused cytoplasmic vacuolization in intestinal tissues, afterward, the administration of Bacillus licheniformis could effectively restore intestinal morphology and inflammation levels. Moreover, the ceftriaxone sodium treatment entirely affected the intestinal microbial ecology, leading to a decrease in microbial abundance. Firmicutes, Proteobacteria, and Epsilonbacteraeota were the most predominant phyla in each of the four groups. Specifically, the MA group (ceftriaxone sodium treatment) resulted in a significant decrease in the relative abundance of 2 bacterial phyla and 20 bacterial genera compared to the administration of Bacillus licheniformis after ceftriaxone sodium treatment. The supplementation of Bacillus licheniformis could increase the growth of Firmicutes and Lactobacillus and encourage the construction of a more mature and stable microbiome. Furthermore, Bacillus licheniformis could restore the intestinal microbiome disorders and inflammation levels following ceftriaxone sodium treatment.

Eating Competence and Aspects Related to a Gluten-Free Diet in Brazilian Adults with Gluten-Related Disorders

This cross-sectional study aims to assess eating competence (EC—an intra-individual approach to food, behaviors, and attitudes related to food) and aspects related to a gluten-free diet (GFD) in Brazilian adults with gluten-related disorders (GRDs). The research was conducted using an online survey with a self-reported instrument consisting of 40 items, organized into three parts: (I) Socioeconomic and demographic data; (II) the Brazilian version of the Eating Competence Satter Inventory (ec-SI2.0™BR); and (III) questions about adherence and difficulties in following the gluten-free diet. EC was measured by the ecSI2.0™BR instrument, with scores ≥32 were considered competent eaters. The instrument was applied nationwide through the GoogleForms® platform from 14 February 2022 to 30 March 2022. The publicity for the recruitment was supported by Brazilian celiac local and national associations (Acelbras and Fenacelbra), pages of food services or personal pages of tips and posts about gluten-related disorders, and specialized stores that offer gluten-free foods. The recruitment occurred through social networks (emails, Facebook groups, WhatsApp, and Instagram). A total of 1030 Brazilians with GRDs answered the questionnaire. Most participants were female, aged 40 years or older, with an income >R$3000, and a high education level. The main difficulty regarding adherence to GFD was the high cost of gluten-free foods. Individuals younger than 40 years old had lower EC scores, with no differences between men and women. Increasing socioeconomic status, schooling, and culinary practices increased the total score. Participants who “never/almost never” felt socially judged because their diet had higher scores for total EC. Competent eaters GRD individuals (EC ≥ 32) were mostly individuals aged ≥40 y/o; with income > R$3000; following a GFD; satisfied with purchased gluten-free products; consuming gluten-free products prepared at home, mainly by themselves; who do not feel judged because of the GRD and who feel that they can live a normal life with GRD. Our study showed that individuals who strictly adhere to the GFD have higher scores on eating competence than those who sometimes follow the treatment.

A therapeutic guide on pediatric irritable bowel syndrome and functional abdominal pain-not otherwise specified

Disorders of the gut-brain interaction negatively impact quality of life and carry a substantial socioeconomic burden. Irritable bowel syndrome (IBS) and functional abdominal pain-not otherwise specified (FAP-NOS) are common functional abdominal pain disorders in childhood. The pathophysiology is not fully understood, and high-quality intervention trials and international guidelines are missing. Therefore, the management of these disorders remains challenging. This review aims to provide an up-to-date overview of therapeutic possibilities for pediatric IBS or FAP-NOS and recommends management strategies. To prevent unnecessary referrals and extensive costs, it is fundamental to make a positive diagnosis of IBS or FAP-NOS in children with chronic abdominal pain with only minimal investigations. A tailor-made approach for each patient, based on the accompanying physical and psychological symptoms, is proposed to date.

CONCLUSION

Shared decision-making including non-pharmacological and pharmacological interventions should be considered and discussed with the family.

WHAT IS KNOWN

• Irritable bowel syndrome and functional abdominal pain-not otherwise specified are common in childhood. • Although the number of treatment options has grown recently, managing these disorders can be challenging and unsatisfactory, and no evidence-based international management guidelines are available.

WHAT IS NEW

• We suggest using a stepwise individualized approach to management, where after first-line management, both non-pharmacological and pharmacological interventions should be discussed.

Food Selectivity and Its Implications Associated with Gastrointestinal Disorders in Children with Autism Spectrum Disorders

Food selectivity (FS) in children with autism spectrum disorders (ASD) is common, and its impact on a nutritional level is known. However, the etiology of gastrointestinal disorders (GID) related to alterations in the intestinal microbiota in children with ASD remains unclear. This article provides a narrative review of the literature on FS from the last 15 years, and its relationship with GID in children with ASD. Sensory aversion in ASD leads to food elimination, based on consistencies, preferences, and other sensory issues. The restriction of food groups that modulate the gut microbiota, such as fruits and vegetables, as well as the fibers of some cereals, triggers an intestinal dysbiosis with increased abundance in Enterobacteriaceae, Salmonella Escherichia/Shigella, and Clostridium XIVa, which, together with an aberrant immune response and a leaky gut, may trigger GID. It is observed that FS can be the product of previous GID. GID could provide information to generate a hypothesis of the bidirectional relationship between FS and GID. Emphasis is placed on the need for more studies with methodological rigor in selecting children with ASD, the need for homogeneous criteria in the evaluation of GID, and the adequate classification of FS in children with ASD.

Evidence-Based and Emerging Diet Recommendations for Small Bowel Disorders

Diet plays a key role in the manifestation and severity of gastrointestinal symptoms, with increasing research interest on the role of diet in small bowel disorders. There are predominantly 3 small bowel conditions that have potential dietary interventions. Self-reported nonceliac gluten/wheat sensitivity is prevalent. Although gluten is believed to be a potential trigger for symptoms, other components of wheat may also be triggers, including fructans, alpha-amylase trypsin inhibitors, and wheat germ agglutinins. The diagnosis can be challenging, given the lack of validated biomarkers. A gluten-free diet that excludes the abovementioned triggers is the cornerstone of treatment; however, unlike celiac disease, there is uncertainty about the level of adherence or whether the gluten-free diet is a lifelong intervention. Several primary gastrointestinal disorders are associated with an increase in inflammatory cells including eosinophils. Diet seems to be an important driver of disease pathogenesis in eosinophilic gastroenteritis, with elimination and elemental diets showing promise in management, with further robust trials required. Small intestinal bacterial overgrowth is an example of microbial dysbiosis, with renewed interest in diet being postulated to cause an adaptive change of the microbes colonizing the small intestine. However, the diagnosis of small intestinal bacterial overgrowth is limited by a lack of sensitive and specific tests, with significant knowledge gaps in relation to therapeutic measures to manage and cure small intestinal bacterial overgrowth. Currently, antimicrobials are the established management option. There have been significant clinical advances in dietary interventions related to the small bowel, but this area is currently a novel and advancing field for both patients and clinicians.

Evidence-Based and Emerging Dietary Approaches to Upper Disorders of Gut-Brain Interaction

Food ingestion is a major symptom trigger in functional esophageal and gastroduodenal disorders and gastroparesis. This review summarizes current knowledge and identifies areas of research on the role of food factors and the opportunities for dietary intervention in these disorders. While many patients experiencing functional esophageal and gastroduodenal disorders identify specific food items as symptom triggers, available data do not allow the identification of specific nutrient groups that are more likely to induce symptoms. In functional dyspepsia (FD), recent studies have shown the potential efficacy of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, although the underlying mechanism of action is unclear. Reports of favorable responses to gluten elimination in patients with FD are confounded by the concomitant benefit of reduced intake of fructans, fermentable oligosaccharides, disaccharides, monosaccharides, and polyols present in wheat. Emerging data based on a 6-food elimination diet and confocal laser endomicroscopic evaluation of mucosal responses to food proteins suggest a role for duodenal allergic reactions in FD symptom generation. In patients with gastroparesis, a low-residue diet has been shown to improve symptoms. Novel dietary approaches under evaluation are the Mediterranean diet and the heating/cooling diet approach.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.

Dietary interventions for functional abdominal pain disorders in children: a systematic review and meta-analysis

BACKGROUND

Functional abdominal pain disorders (FAPDs) are common among children and are associated with decreased quality of life and school attendance. Several dietary interventions have been suggested to improve symptoms of FAPDs. This systematic review assessed the efficacy and safety of dietary interventions for pediatric FAPDs.

DESIGN AND METHODS

Electronic databases were searched (inception-October 2021). Systematic reviews or RCTs were included if children (4-18 years) with FAPDs were treated with dietary interventions and compared to placebo, no diet or any other diet. Data extraction and assessment of quality of evidence based on GRADE system was independently performed by two review authors. Outcomes were treatment success, pain intensity and frequency, and withdrawal due to adverse events.

RESULTS

Twelve articles were included, representing data of 819 pediatric FAPD patients. Trials investigating fibers, FODMAP diet, fructans, fructose-restricted diet, prebiotic (inulin), serum-derived bovine immunoglobulin, and vitamin D supplementation were included. We found very low-certainty evidence that the use of fibers leads to higher treatment success (NNT = 5).

CONCLUSION

Based on current evidence, the use of fibers can be discussed in daily practice. High-quality intervention trials are highly needed to investigate if other dietary interventions are effective in the treatment of pediatric FAPD.

Patterning Large-Scale Nanostructured Microarrays on Coverslip for Sensitive Plasmonic Detection of Aqueous Gliadin Traces

User-friendly devices for detecting low gliadin content in commercial foods are of extreme importance for people with gluten diseases. With this concern, the present work proposes a rapid and sensitive optical nanostructured microarrays platform for the detection of gliadin using specific anti-gliadin IgG antibodies immobilized on annealed gold nanostructures (AuNPs) obtained after the high annealing process (550 °C) of gold thin films evaporated on commercial glass coverslips. Localized Surface Plasmon Resonance (LSPR) immunosensing of gliadin in the range of 0.1 ppm to 1000 ppm is successfully achieved. In addition, the biofunctionalization protocol was used for gluten screening in five food complex products.

Inflammatory and Microbiota-Related Regulation of the Intestinal Epithelial Barrier

The intestinal epithelial barrier (IEB) is one of the largest interfaces between the environment and the internal milieu of the body. It is essential to limit the passage of harmful antigens and microorganisms and, on the other side, to assure the absorption of nutrients and water. The maintenance of this delicate equilibrium is tightly regulated as it is essential for human homeostasis. Luminal solutes and ions can pass across the IEB via two main routes: the transcellular pathway or the paracellular pathway. Tight junctions (TJs) are a multi-protein complex responsible for the regulation of paracellular permeability. TJs control the passage of antigens through the IEB and have a key role in maintaining barrier integrity. Several factors, including cytokines, gut microbiota, and dietary components are known to regulate intestinal TJs. Gut microbiota participates in several human functions including the modulation of epithelial cells and immune system through the release of several metabolites, such as short-chain fatty acids (SCFAs). Mediators released by immune cells can induce epithelial cell damage and TJs dysfunction. The subsequent disruption of the IEB allows the passage of antigens into the mucosa leading to further inflammation. Growing evidence indicates that dysbiosis, immune activation, and IEB dysfunction have a role in several diseases, including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and gluten-related conditions. Here we summarize the interplay between the IEB and gut microbiota and mucosal immune system and their involvement in IBS, IBD, and gluten-related disorders.

Non-Celiac Gluten/Wheat Sensitivity: Clinical Characteristics and Microbiota and Mycobiota Composition by Response to the Gluten Challenge Test

The aims of this observational “proof-of-concept” study were to analyze the clinical/psychological characteristics and gut microbiota/mycobiota composition of individuals with suspected non-celiac gluten/wheat sensitivity (NCGS/WS) according to responses to the double-blind-placebo-controlled (DBPC) crossover gluten challenge test. Fifty individuals with suspected NCGS/WS were subjected to the DBPC challenge test; anthropometric measurements, psychometric questionnaires, and fecal samples were collected. Twenty-seven (54%) participants were gluten responsive (NCGS), and 23 were placebo responsive, with an order effect. NCGS individuals displayed a significantly lower risk of eating disorders and a higher mental health score when compared to placebo-responsive participants, confirmed by multiple logistic regression analyses (OR = 0.87; 95% CI 0.76–0.98, p = 0.021, and OR = 1.30; 95% CI 1.06–1.59, p = 0.009, respectively). Principal coordinate analyses based on microbiota composition showed a separation by the DBPC response (p = 0.039). For Bacteroides (p = 0.05) and Parabacteroides (p = 0.007), the frequency of amplicon sequence variants was lower, and that for Blautia (p = 0.009) and Streptococcus (p = 0.004) was higher in NCGS individuals at multiple regression analyses. No difference in the mycobiota composition was detected between the groups. In conclusion, almost half of the individuals with suspected gluten sensitivity reported symptoms with placebo; they showed lower mental health scores, increased risk for eating disorders, and a different gut microbiota composition.

Histamine Intolerance Originates in the Gut

Histamine intolerance (HIT) is assumed to be due to a deficiency of the gastrointestinal (GI) enzyme diamine oxidase (DAO) and, therefore, the food component histamine not being degraded and/or absorbed properly within the GI tract. Involvement of the GI mucosa in various disorders and diseases, several with unknown origin, and the effects of some medications seem to reduce gastrointestinal DAO activity. HIT causes variable, functional, nonspecific, non-allergic GI and extra-intestinal complaints. Usually, evaluation for HIT is not included in differential diagnoses of patients with unexplained, functional GI complaints or in the here-listed disorders and diseases. The clinical diagnosis of HIT is challenging, and the thorough anamnesis of all HIT-linked complaints, using a standardized questionnaire, is the mainstay of HIT diagnosis. So far, DAO values in serum have not been established to correlate with DAO activity in the gut, but the diagnosis of HIT may be supported with determination of a low serum DAO value. A targeted dietary intervention, consisting of a histamine-reduced diet and/or supplementation with oral DAO capsules, is helpful to reduce HIT-related symptoms. This manuscript will present why histamine should also be taken into account in the differential diagnoses of patients with various diseases and disorders of unknown origin, but with association to functional gastrointestinal complaints. In this review, we discuss currently increasing evidence that HIT is primarily a gastrointestinal disorder and that it originates in the gut.