Diet in irritable bowel syndrome

The emerging role of biotechnological advances and artificial intelligence in tackling gluten sensitivity

Gluten comprises an intricate network of hundreds of related but distinct proteins, mainly "gliadins" and "glutenins," which play a vital role in determining the rheological properties of wheat dough. However, ingesting gluten can trigger severe conditions in susceptible individuals, including celiac disease, wheat allergy, or non-celiac gluten sensitivity, collectively known as gluten-related disorders. This review provides a panoramic view, delving into the various aspects of gluten-triggered disorders, including symptoms, diagnosis, mechanism, and management. Though a gluten-free diet remains the primary option to manage gluten-related disorders, the emerging microbial and plant biotechnology tools are playing a transformative role in reducing the immunotoxicity of gluten. The enzymatic hydrolysis of gluten and the development of gluten-reduced/free wheat lines using RNAi and CRISPR/Cas technology are laying the foundation for creating safer wheat products. In addition to biotechnological interventions, the emerging artificial intelligence technologies are also bringing about a paradigm shift in the diagnosis and management of gluten-related disorders. Here, we provide a comprehensive overview of the latest developments and the potential these technologies hold for tackling gluten sensitivity.

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

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

Investigation of the association between habitual dietary FODMAP intake, metabolic parameters, glycemic status, and anthropometric features among apparently healthy overweight and obese individuals

BACKGROUND

The predisposition of humans to metabolic syndrome is affected by many factors, including diet and lifestyle. Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are a set of carbohydrates that are fermented by gut microbiota. In animal studies, supplementation with FODMAP-rich diets as prebiotics can alter body composition and gut microbiota. This study evaluates any relationship between FODMAP and metabolic syndrome risk factors among adults with metabolic syndrome in Iran.

METHODS

This cross-sectional study is based on sociodemographic information from 347 overweight and obese participants selected from outpatient clinics through public declaration. Participants body composition and anthropometric measures were also determined. A validated Food Frequency Questionnaire (FFQ) with 168 questions was used to collect dietary data. Biochemical parameters, including serum total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), fasting serum glucose (FSG), and insulin levels, were determined by enzymatic methods. In addition, the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI) were calculated.

RESULTS

In moderate FODMAP and low FODMAP groups, lower waist-to-hip ratio (WHR) and higher fat-free mass (FFM) were achieved in higher tertiles. In high FODMAP groups, higher systolic blood pressure (SBP) was shown in the higher tertile (P < 0.05). Higher insulin, HOMA-IR, and lower QUICKI in the second tertile of the high FODMAP group were also observed.

CONCLUSION

Findings of this study highlight the potential role of FODMAP in managing metabolic syndrome and open a new field of research.

Enhancing Bread's Benefits: Investigating the Influence of Boosted Native Sourdough on FODMAP Modulation and Antioxidant Potential in Wheat Bread

This study aimed to assess the impact of bacterial species and fermentation time on wheat bread quality, FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) content, and antioxidant activity of wheat bread, utilizing boosted native sourdough as a novel approach to enhance bread production. The incorporation of lactic acid bacteria strains, i.e., Lacticaseibacillus casei and Lactiplantibacillus plantarum, during 72 h fermentation significantly reduced FODMAP content to less than 0.1 g/100 g of wheat bread. Extending the fermentation time to 72 h notably increased the polyphenol content to 145.35 mg gallic acid (GA) per 100 g in the case of spontaneous fermentation and to 151.11 and 198.73 mg GA/100 g in the case of sourdoughs inoculated with L. casei and L. plantarum, respectively. While the treatment yielded positive effects on FODMAP modulation and antioxidant activity, it is crucial to acknowledge its impact on some organoleptic properties, such as aroma and flavor, which, despite good overall bread quality, have changed as a result of prolonged fermentation time. The study results indicate that choosing specific bacterial species and controlling fermentation time can effectively reduce FODMAPs and boost antioxidants. These findings contribute to the understanding of sourdough-based interventions in bread production, offering insights for the development of healthier and nutritionally improved wheat bread products.

Nutrition, Physical Activity and Supplementation in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a chronic, recurrent functional disorder of the intestine diagnosed based on the Rome IV criteria. Individuals suffering from IBS often associate the severity of their symptoms with the food they consume, leading them to limit the variety of foods they eat and seek information that could help them determine the appropriate selection of dietary items. Clear nutritional recommendations have not been established thus far. NICE recommends a rational approach to nutrition and, if necessary, the short-term implementation of a low FODMAP diet. Currently, the FODMAP diet holds the greatest significance among IBS patients, although it does not yield positive results for everyone affected. Other unconventional diets adopted by individuals with IBS lack supporting research on their effectiveness and may additionally lead to a deterioration in nutritional status, as they often eliminate foods with high nutritional value. The role of physical activity also raises questions, as previous studies have shown its beneficial effects on the physical and mental well-being of every individual, and it can further help alleviate symptoms among people with IBS. Supplementation can be a supportive element in therapy. Attention is drawn to the use of probiotics, vitamin D, and psyllium husk/ispaghula. This review aims to analyze the existing scientific research to determine the impact of various food items, physical activity, and dietary supplementation with specific components through dietary supplements on the course of IBS.

Soluble Dietary Fibers as Antihyperlipidemic Agents: A Comprehensive Review to Maximize Their Health Benefits

The number of hypercholesterolemic people is increasing rapidly worldwide, with elevated lipid profiles representing a major risk factor of coronary heart diseases. Dietary intervention was shown to improve the lipid profile, thus enhancing the quality of life. Dietary fiber is a nondigestible form of carbohydrates, due to the lack of the digestive enzyme in humans required to digest fiber, and is classified according to its water solubility properties as either soluble (SDF) or insoluble dietary fiber (IDF). Consumption of SDF is associated with several health benefits such as reduced lipid levels, lower blood pressure, improved blood glucose control, improved immune function, and reduced inflammation. SDF has been shown to lower blood cholesterol by several action mechanisms including directly due to the gelling, mucilaginous, and viscous fiber nature, and indirectly due to its fermented products and modulation of the gut microbiome. This review aims to provide a holistic overview on how SDF impacts the lipid profile. We start by providing an overview of the chemical structure of the major SDFs including mucilage, gums (gum arabic and guar gum), pectin, and inulin.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

Efficacy of diet restriction with or without probiotic for treatment of patients with IBS-D: Phase I-II clinical trial

BACKGROUND AND AIM

Diet is a major contributor to irritable bowel syndrome (IBS) and is also a powerful tool for treatment of IBS. This study compared two diets and explored the effectiveness of the diets when combined with a probiotic for treatment of IBS-D patients.

METHODS

Phase I, patients were randomized into groups; control, cold/spicy/fried restricted diet (CSF res diet), IgG positive restricted diet (IgG res diet), and a combination both diets (CSF + IgG res diet). Phase II, patients were randomized into IgG res diet + placebo and IgG res diet + probiotic. Both interventions were 12 weeks in duration. Symptom Severity Scale (IBS-D-SSS) and IgG titer were assessed at the beginning and the end of the study.

RESULTS

Totals of 214 and 167 patients completed the two parts of the study, respectively. After intervention, IBS-D-SSS and TIgG grade were significantly improved compared to baseline, with results similar to the control group. In general, there were decreases in IBS-D-SSS and TIgG grade that were significantly different among the groups. There were exceptions; no differences were observed for IBS-D-SSS between the IgG res diet and CSF + IgG res diet, or TIgG grade between the CSF res diet, IgG res diet, and CSF + IgG res diet. However, the CSF res diet and IgG res diet had a synergistic effect that decreased IBS-D-SSS and TIgG titer, with a greater contribution by the IgG res diet. Therefore, we evaluated the IgG res diet with either placebo or probiotic and found that IBS-D-SSS and TIgG grade decreased from baseline. There was a significant decrease in IBS-D-SSS with the probiotic but TIgG grade was not significantly different between the IgG diet + placebo and IgG diet + probiotic diet.

CONCLUSIONS

Both the CSF res diet and IgG res diet improved IBS symptoms and demonstrated synergy, although the IgG res diet had a greater contribution. Further, when intolerant foods cannot be eliminated from a diet, avoiding uncooked, cold, spicy, fried, and alcoholic foods is a superior choice. The IgG res diet combined with Bifidobacteria was the best dietary choice and may function though a non-IgG pathway.

History of trying exclusion diets and association with avoidant/restrictive food intake disorder in neurogastroenterology patients: A retrospective chart review

BACKGROUND

Exclusion diets for gastrointestinal symptom management have been hypothesized to be a risk factor for avoidant/restrictive food intake disorder (ARFID; a non-body image-based eating disorder). In a retrospective study of pediatric and adult neurogastroenterology patients, we aimed to (1) identify the prevalence and characteristics of an exclusion diet history and (2) evaluate if an exclusion diet history was concurrently associated with the presence of ARFID symptoms.

METHODS

We conducted a chart review of 539 consecutive referrals (ages 6-90, 69% female) to adult (n = 410; January-December 2016) and pediatric (n = 129; January 2016-December 2018) neurogastroenterology clinics. Masked coders (n = 4) retrospectively applied DSM-5 criteria for ARFID and a separate coder assessed documentation of exclusion diet history. We excluded patients with no documentation of diet in the chart (n = 35) or who were not orally fed (n = 9).

RESULTS

Of 495 patients included, 194 (39%) had an exclusion diet history, and 118 (24%) had symptoms of ARFID. Of reported diets, dairy-free was the most frequent (45%), followed by gluten-free (36%). Where documented, exclusion diets were self-initiated by patients/parents in 66% of cases, and recommended by gastroenterology providers in 30%. Exclusion diet history was significantly associated with the presence of ARFID symptoms (OR = 3.12[95% CI 1.92-5.14], p < 0.001).

CONCLUSIONS

History of following an exclusion diet was common and was most often patient-initiated among pediatric and adult neurogastroenterology patients. As patients with self-reported exclusion diet history were over three times as likely to have ARFID symptoms, providers should be cognizant of this potential association when considering dietary interventions.

Nutritional intervention in the management of non-alcoholic fatty liver disease

Lifestyle modification is the primary intervention to control NAFLD progression, but despite evidence-based effectiveness it is difficult to distinguish the benefits of nutrition from physical activity and the optimal diet composition is not established. Macronutrients as saturated fatty acids, sugars and animal proteins are harmful in NAFLD and the Mediterranean Diet reducing sugar, red meat and refined carbohydrates and increasing unsaturated-fatty-acids was reported to be beneficial. However one size cannot fit all since NAFLD is a multifaceted syndrome encompassing many diseases of unknown etiologies, different clinical severity and outcomes. Studies of the intestinal metagenome, provided new insights into the physio-pathological interplay between intestinal microbiota and NAFLD. How much the microbiota heterogeneity can influence response to diet remains unknown. New knowledge indicates that AI guided personalized nutrition based on clinic-pathologic and genetic data combined with pre/post nutritional intervention gut metagenomics/metabolomics will be part of the future management of NAFLD.

The association between dietary acid load and odds and severity of irritable bowel syndrome in adults

No study has been conducted to investigate the association between dietary acid load and irritable bowel syndrome (IBS). So, this cross-sectional study was performed to investigate the association between dietary acid load and odds of IBS, its severity, and IBS subtypes. A sample of 3362 Iranian subjects was selected from health centers in Isfahan province. A validated semi-quantitative food frequency questionnaire (DS-FFQ) was applied to estimate dietary intakes. The dietary acid load was measured using net endogenous acid production (NEAP), dietary acid load (DAL), and potential renal acid load (PRAL) scores. In crude models, the highest compared with the lowest category of the PRAL score was significantly associated with increased odds of IBS severity in participants with BMI ≥ 25 (kg/m²) (OR = 1.54; 95% CI = (1.03-2.32). Also, the results indicated a significant positive association between the PARL and odds of mixed subtype of IBS (OR = 1.74; 95% CI = (1.11-2.74); P trend = 0.02). In propensity score-adjusted model with potential confounders, only a positive association was found between PRAL and odds of mixed subtype of IBS (OR = 1.78; 95% CI = (1.05-3.00); P trend = 0.03). The DAL and NEAP scores tended to show non-significant similar findings. This study indicates that dietary acid load might be associated with odds of mixed type of IBS. However, further research is warranted to infer these findings.

The association between dietary acid load and odds and severity of irritable bowel syndrome in adults

No study has been conducted to investigate the association between dietary acid load and irritable bowel syndrome (IBS). So, this cross-sectional study was performed to investigate the association between dietary acid load and odds of IBS, its severity, and IBS subtypes. A sample of 3362 Iranian subjects was selected from health centers in Isfahan province. A validated semi-quantitative food frequency questionnaire (DS-FFQ) was applied to estimate dietary intakes. The dietary acid load was measured using net endogenous acid production (NEAP), dietary acid load (DAL), and potential renal acid load (PRAL) scores. In crude models, the highest compared with the lowest category of the PRAL score was significantly associated with increased odds of IBS severity in participants with BMI ≥ 25 (kg/m2) (OR = 1.54; 95% CI = (1.03-2.32). Also, the results indicated a significant positive association between the PARL and odds of mixed subtype of IBS (OR = 1.74; 95% CI = (1.11-2.74); P trend = 0.02). In propensity score-adjusted model with potential confounders, only a positive association was found between PRAL and odds of mixed subtype of IBS (OR = 1.78; 95% CI = (1.05-3.00); P trend = 0.03). The DAL and NEAP scores tended to show non-significant similar findings. This study indicates that dietary acid load might be associated with odds of mixed type of IBS. However, further research is warranted to infer these findings.

An ESPGHAN Position Paper on the Use of Low-FODMAP Diet in Pediatric Gastroenterology

Excluding oligo-, di-, monosaccharides and polyols (FODMAPs) from the diet is increasingly being used to treat children with gastrointestinal complaints. The aim of this position paper is to review the available evidence on the safety and efficacy of its use in children and provide expert guidance regarding practical aspects in case its use is considered . Members of the Gastroenterology Committee, the Nutrition Committee and the Allied Health Professionals Committee of the European Society for Pediatric Gastroenterology Hepatology and Nutrition contributed to this position paper. Clinical questions regarding initiation, introduction, duration, weaning, monitoring, professional guidance, safety and risks of the diet are addressed. A systematic literature search was performed from 2005 to May 2021 using PubMed, MEDLINE and Cochrane Database of Systematic Reviews. In the absence of evidence, recommendations reflect the expert opinion of the authors. The systematic literature search revealed that the low-FODMAP diet has not been comprehensively studied in children. Indications and contraindications of the use of the diet in different pediatric gastroenterological conditions are discussed and practical recommendations are formulated. There is scarce evidence to support the use of a low-FODMAP diet in children with Irritable Bowel Syndrome and no evidence to recommend its use in other gastrointestinal diseases and complaints in children. Awareness of how and when to use the diet is crucial, as a restrictive diet may impact nutritional adequacy and/or promote distorted eating in vulnerable subjects. The present article provides practical safety tips to be applied when the low-FODMAP diet is considered in children.

The relationship between meal regularity with Irritable Bowel Syndrome (IBS) in adults

BACKGROUND

The irregular meal pattern and meal-skipping might be related to irritable bowel syndrome (IBS), however, findings of previous investigations are contradictory. We aimed to examine the relation of meal regularity with IBS in Iranian adult population.

METHODS

Data on 4599 adults who worked in 50 different health centers were used in this cross-sectional study. Dietary habits were measured using a pretested questionnaire. IBS identification was performed through the use of a modified version of Rome III questionnaire.

RESULTS

IBS was prevalent among 18.6% of men and 24.1% of women. After adjustment for potential confounders, those with regular meal pattern, in comparison to those with irregular meals, had 40% lower odds for IBS (OR:0.60, 95%CI: 0.41-0.87). Individuals with regular meals had also 82 lower risk for IBS-Mixed, in comparison to those who had irregular meals (OR:0.18, 0.95%CI: 0.08-0.43). Stratified analysis by gender revealed that women with regular meals, compared with those who did not, had 44% lower risk for IBS (OR: 0.56, 0.95%CI: 0.34-0.91). Normal-weight individuals who had regular meal pattern, compared to those who did not, had 63% lower risks for IBS (OR:0.37, 95%CI: 0.22-0.64). Furthermore, subjects who had regular meal pattern had 53% lower risk for severe symptoms of IBS (OR:0.47, 95%CI: 0.30-0.71).

CONCLUSION

We found that participants with regular meal pattern had reduced odds of IBS, IBS-Mixed and the syndrome severity. Meal regularity was also linked to reduced IBS prevalence in women, and in normal-weight individuals. More prospective studies are needed to affirm these associations.

Soluble Dietary Fiber, One of the Most Important Nutrients for the Gut Microbiota

Dietary fiber is a widely recognized nutrient for human health. Previous studies proved that dietary fiber has significant implications for gastrointestinal health by regulating the gut microbiota. Moreover, mechanistic research showed that the physiological functions of different dietary fibers depend to a great extent on their physicochemical characteristics, one of which is solubility. Compared with insoluble dietary fiber, soluble dietary fiber can be easily accessed and metabolized by fiber-degrading microorganisms in the intestine and produce a series of beneficial and functional metabolites. In this review, we outlined the structures, characteristics, and physiological functions of soluble dietary fibers as important nutrients. We particularly focused on the effects of soluble dietary fiber on human health via regulating the gut microbiota and reviewed their effects on dietary and clinical interventions.

Overlap between irritable bowel syndrome and hypermobile Ehlers-Danlos syndrome: An unexplored clinical phenotype?

Irritable bowel syndrome (IBS) is common, but its cause remains unknown. IBS patients present with gastrointestinal (GI) symptoms such as abdominal pain with altered bowel habits; however, some patients also have non-GI symptoms including muscle and joint pains. It is thus plausible that within large IBS cohorts, subgroups exist with distinct clinical phenotypes. Yet, these subgroups have not been clearly identified or characterized. Due to lack of segmentation, treatment-focused symptomatic management is similar for all with IBS and follows indiscriminate algorithms regardless of possible differing clinical phenotype. This universal approach to IBS management may account for the reported lack of efficacy of treatment. One emerging subgroup receiving increasing attention is that with overlap IBS and the underlying heritable connective tissue disorder, hypermobile Ehlers-Danlos syndrome (hEDS). Current evidence suggests that up to 62% of patients with hEDS suffer from IBS. However, despite recognition of the presence of IBS in hEDS, this overlap IBS/hEDS group has not been characterized and these patients are managed in a similar way to those with IBS alone. Future studies are required to characterize and deep phenotype in this overlap IBS/hEDS group.

The prevalence of disorders of the gut-brain axis in type 2 diabetes mellitus patients with metabolic dysfunction-associated fatty liver disease: an observational study

BACKGROUND AND STUDY AIM

Disorders of the gut-brain axis (DGBI) and metabolic dysfunction-associated liver disease (MAFLD) are frequently diagnosed and exhibit pathophysiological similarities. This study aimed to estimate the prevalence of DGBI in type 2 diabetes mellitus (T2DM) patients with MAFLD.

PATIENTS AND METHODS

In this single center, observational study, in adults with T2DM demographics, diabetes-related parameters and liver tests were recorded. MAFLD was defined by the presence of hepatic steatosis on imaging. Functional dyspepsia (FD) and irritable bowel syndrome (IBS) were diagnosed based on Rome IV criteria. Quality of life (QOL), anxiety levels and depression levels were documented by validated questionnaires.

RESULTS

We included 77 patients, 44 with and 33 without steatosis. There were no significant differences in age, body mass index (BMI), waist circumference, HbA1c levels or metformin use between groups. IBS was significantly more prevalent in the liver steatosis group (9/44 vs. 2/33, p = .037), while a similar trend was observed for FD (9/35 vs. 2/31, p = .103). No differences were found in anxiety, depression and overall QOL. However, QOL subscales for health worry, food avoidance and social reaction were significantly higher in the liver steatosis group.

CONCLUSIONS

In otherwise comparable T2DM patients, DGBI, and especially IBS, are more prevalent in the presence of MAFLD. This difference could not be attributed to increased levels of anxiety or depression. Future research should target the underlying pathophysiological mechanisms.

A Low-FODMAP Diet Improves the Global Symptoms and Bowel Habits of Adult IBS Patients: A Systematic Review and Meta-Analysis

Background: A low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet has been reported to be associated with improving the symptoms of irritable bowel syndrome (IBS); however, its efficacy as evaluated by different studies remains controversial. Objective: A systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted to explore the efficacy of a low-FODMAP diet (LFD) in alleviating the symptoms of IBS. Methods: A search of the literature for RCTs that assessed the efficacy of an LFD in treating IBS patients was conducted using the electronic databases PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science. The searches in each database were conducted from the inception of the database to February 2021. Two independent reviewers screened citations and a third reviewer resolved disagreements. Two independent reviewers also performed eligibility assessments and data extraction. The RCTs that evaluated LFDs vs. a normal IBS or usual diet and assessed changes of IBS symptoms were included in the search. Data were synthesized as the relative risk of global symptoms improvement, mean difference of IBS Severity Scoring System (IBS-SSS) score, sub-items of IBS-SSS irritable bowel syndrome-related quality of life (IBS-QOL), hospital anxiety and depression scale (HADS), stool consistency/frequency, and body mass index (BMI) using a random effects model. The risk of bias was assessed using Risk of Bias Tool 2 (RoB 2). The bias of publication was assessed based on Egger's regression analysis. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Results: A total of 2,768 citations were identified. After full-text screening, a total of 10 studies were eligible for the systematic review and were subsequently used to compare an LFD with various control interventions in 511 participants. An LFD was associated with the improvement of global symptoms [n = 420; Risk Ratio (RR) = 1.54; 95% Confidence Interval (CI) 1.18 to 2; I 2 = 38%], improvement of stool consistency [n = 434; Mean difference (MD) = -0.25; 95% CI -0.44 to -0.06; I 2= 19%), and a reduction trend of stool frequency (n = 434; MD = -0.28; 95% CI -0.57 to 0.01; I 2 = 68%) compared with control interventions. There was no statistically significant change in IBS-QOL (n = 484; MD = 2.77; 95% CI -2 to 7.55; I 2 = 62%), anxiety score (n = 150; MD = -0.45; 95% CI -3.38 to 2.49; I 2 = 86%), depression score (n = 150; MD = -0.05; 95% CI -2.5 to 2.4; I 2 = 88%), and BMI (n = 110; MD = -0.22; 95% CI -1.89 to 1.45; I 2 = 14%). The overall quality of the data was "moderate" for "global improvement of IBS symptom," "stool consistency," "stool consistency for IBS with diarrhea (IBS-D)," and "stool frequency for IBS-D," and "low" or "very low" for other outcomes according to GRADE criteria. Conclusion: An LFD is effective in reducing the global symptoms and improving the bowel habits of adult IBS patients. The efficacy for IBS-D patients can also be more pronounced. Systematic Review Registration: CRD42021235843.

An Update on the Assessment and Management of Pediatric Abdominal Pain

Chronic abdominal pain is very common in children and adolescent and results in high personal and social costs. Most youth with chronic abdominal pain fulfill criteria for a functional abdominal pain disorder (FAPD) as defined by Rome criteria. These are complex conditions with a wide array of biological, psychological, and social factors contributing to the experience of pain. The purpose of the current review is to provide an overview of the pathophysiology of FAPDs and an up-to-date summary of the literature related to FAPDs in children and adolescents, with additional focus on several areas (eg, diet and probiotics) where patients and families frequently have questions or implement self-directed care. We also provide an approach to the assessment and treatment of pediatric FAPDs focusing on the robust literature regarding psychological interventions and much sparser literature regarding medication treatment.

Dietary modulation of gut microbiota for the relief of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a frequently diagnosed gastrointestinal (GI) disorder characterized by recurrent abdominal pain, bloating, and changes in the stool form or frequency without any structural changes and overt inflammation. It is not a life-threatening condition but causes a considerable level of discomfort and distress. Among the many pathophysiologic factors, such as altered GI motility, visceral hypersensitivity, and low-grade mucosal inflammation, as well as other immunologic, psychologic, and genetic factors, gut microbiota imbalance (dysbiosis), which is frequently found in IBS, has been highlighted as an etiology of IBS. Dysbiosis may affect gut mucosal homeostasis, immune function, metabolic regulation, and even visceral motor function. As diet is shown to play a fundamental role in the gut microbiota profile, this review discusses the influence of diet on IBS occurring through the modulation of gut microbiota. Based on previous studies, it appears that dietary modulation of the gut microbiota may be effective for the alleviation of IBS symptoms and, also an effective IBS management strategy based on the underlying mechanism; especially because, IBS currently has no specific treatment owing to its uncertain etiology.

The Effect of the Low FODMAP Diet on Gastrointestinal Symptoms, Behavioral Problems and Nutrient Intake in Children with Autism Spectrum Disorder: A Randomized Controlled Pilot Trial

Some research suggests that GI symptoms seen in children with ASD may relate to behavior problems. The objective of this pilot study was to assess the effect of the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet on GI and behavioral problems in children with ASD. At follow-up, the low FODMAP diet group had significant relief in some GI problems compared with both baseline in the group and control group. At baseline and at follow-up, there were no significant differences in behavioral problems between the low FODMAP diet group and the control group. Randomized controlled studies including larger sample sizes are needed to confirm the effects of low FODMAP diets in children with autism who have gastrointestinal problems.

Effect of Inoculated Lactic Acid Fermentation on the Fermentable Saccharides and Polyols, Polyphenols and Antioxidant Activity Changes in Wheat Sourdough

Inoculation of sourdough allows the fermentation medium to be dominated by desired microorganisms, which enables determining the kinetics of the conversion of chemical compounds by individual microorganisms. This knowledge may allow the design of functional food products with health features dedicated to consumers with special needs. The aim of the study was to assess the dynamics of transformations of fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) compounds from wheat flour as well as their antioxidant activity during inoculated and spontaneous sourdough fermentation. The FODMAP content in grain products was determined by the fructan content with negligible amounts of sugars and polyols. To produce a low-FODMAP cereal product, the fermentation time is essential. The 72 h fermentation time of L. plantarum-inoculated sourdough reduced the FODMAP content by 91%. The sourdough fermentation time of at least 72 h also positively influenced the content of polyphenols and antioxidant activity, regardless of the type of fermentation. The inoculation of both L. plantarum and L. casei contributed to a similar degree to the reduction in FODMAP in sourdough compared to spontaneous fermentation.

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

Background/Aims

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

Methods

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

Results

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

Conclusions

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

The distribution and chemical coding of enteroendocrine cells in Trypanosoma cruzi-infected individuals with chagasic megacolon

Chagas disease is caused by the parasite, Trypanosoma cruzi that causes chronic cardiac and digestive dysfunction. Megacolon, an irreversible dilation of the left colon, is the main feature of the gastrointestinal form of Chagas disease. Patients have severe constipation, a consequence of enteric neuron degeneration associated with chronic inflammation. Dysmotility, infection, neuronal loss and a chronic exacerbated inflammation, all observed in Chagas disease, can affect enteroendocrine cells (EEC) expression, which in turn, could influence the inflammatory process. In this study, we investigated the distribution and chemical coding of EEC in the dilated and non-dilated portion of T. cruzi-induced megacolon and in non-infected individuals (control colon). Using immunohistochemistry, EECs were identified by applying antibodies to chromogranin A (CgA), glucagon-like peptide 1 (GLP-1), 5-hydroxytryptamine (5-HT), peptide YY (PYY) and somatostatin (SST). Greater numbers of EEC expressing GLP-1 and SST occurred in the dilated portion compared to the non-dilated portion of the same patients with Chagas disease and in control colon, but numbers of 5-HT and PYY EEC were not significantly different. However, it was noticeable that EEC in which 5-HT and PYY were co-expressed were common in control colon, but were rare in the non-dilated and absent in the dilated portion of chagasic megacolon. An increase in the number of CgA immunoreactive EEC in chagasic patients reflected the increases in EEC numbers summarised above. Our data suggests that the denervation and associated chronic inflammation are accompanied by changes in the number and coding of EEC that could contribute to disorders of motility and defence in the chagasic megacolon.

The role of diet in the pathophysiology and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder that reportedly affects 5% to 20% of the world population. The etiology of IBS is not completely understood, but diet appears to play an important role in its pathophysiology. Asian diets differ considerably from those in Western countries, which might explain differences in the prevalence, sex, and clinical presentation seen between patients with IBS in Asian and Western countries. Dietary regimes such as a low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet and the modified National Institute for Health and Care Excellence (NICE) diet improve both symptoms and the quality of life in a considerable proportion of IBS patients. It has been speculated that diet is a prebiotic for the intestinal microbiota and favors the growth of certain bacteria. These bacteria ferment the dietary components, and the products of fermentation act upon intestinal stem cells to influence their differentiation into enteroendocrine cells. The resulting low density of enteroendocrine cells accompanied by low levels of certain hormones gives rise to intestinal dysmotility, visceral hypersensitivity, and abnormal secretion. This hypothesis is supported by the finding that changing to a low-FODMAP diet restores the density of GI cells to the levels in healthy subjects. These changes in gut endocrine cells caused by low-FODMAP diet are also accompanied by improvements in symptoms and the quality of life.

The gut virome in Irritable Bowel Syndrome differs from that of controls

Irritable Bowel Syndrome (IBS), the most common gastrointestinal disorder, is diagnosed solely on symptoms. Potentially diagnostic alterations in the bacterial component of the gut microbiome (the bacteriome) are associated with IBS, but despite the known role of the virome (particularly bacteriophages), in shaping the gut bacteriome, few studies have investigated the virome in IBS. We performed metagenomic sequencing of fecal Virus-Like Particles (VLPs) from 55 patients with IBS and 51 control individuals. We detected significantly lower alpha diversity of viral clusters comprising both known and novel viruses (viral 'dark matter') in IBS and a significant difference in beta diversity compared to controls, but not between IBS symptom subtypes. The three most abundant bacteriophage clusters belonged to the Siphoviridae, Myoviridae, and Podoviridae families (Order Caudovirales). A core virome (defined as a cluster present in at least 50% of samples) of 5 and 12 viral clusters was identified in IBS and control subjects, respectively. We also identified a subset of viral clusters that showed differential abundance between IBS and controls. The virome did not co-vary significantly with the bacteriome, with IBS clinical subtype, or with Bile Acid Malabsorption status. However, differences in the virome could be related back to the bacteriome as analysis of CRISPR spacers indicated that the virome alterations were at least partially related to the alterations in the bacteriome. We found no evidence for a shift from lytic to lysogenic replication of core viral clusters, a phenomenon reported for the gut virome of patients with Inflammatory Bowel Disease. Collectively, our data show alterations in the virome of patients with IBS, regardless of clinical subtype, which may facilitate development of new microbiome-based therapeutics.

Irritable Bowel Syndrome: News from an Old Disorder

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder, which can affect all members of a society, regardless of age, sex, race or socioeconomic status. Because of its high prevalence and chronic nature, it represents a significant economic burden. In fact, these patients have a relevant impairment of their quality of life, which limits their work productivity and daily social activities, especially when it is associated with other disorders, such as anxiety and depression. The diagnosis of IBS relies on symptom-based diagnostic criteria with normal results on a limited number of complementary tests that rule out other possible diagnoses. The aetiology of this condition is incompletely established. However, evidence suggests that it is a multifactorial disorder with several different mechanisms that have been implicated as responsible for the symptoms. Since the treatment strategy is usually based on predominant symptoms and their severity, it is important to recognise the underlying mechanisms in order to successfully relief the visceral pain and altered bowel habits. The aim of this non-systematic review of the literature was to explore the pathophysiology and treatment options of IBS, highlighting the most recent evidence, from the new Rome IV criteria to the new drug armamentarium.

Technological methods for reducing the content of fructan in rye bread

The irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract that may afflict even 12% of the European population. One of the ways to counteract IBS-related ailments is to implement a diet with reduced contents of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). The prevailing components from the FODMAPs group that may be found in rye bread include fructans. The study was conducted with endosperm and wholemeal rye flours. Dough was prepared from both flours with the use of two methods: I-stage method—with the addition of dry leavening—and II-stage method with the use of a sourdough produced with Lactobacillus plantarum, and all with fermentation times of 90, 120, 150, and 180 min. After baking, bread loaves were subjected to quality and consumer analysis and fructan content determination. The endosperm rye flour used for bread-making revealed better baking properties. Bread made of this flour had a higher loaf volume and received higher scores in the consumer assessment than bread made with wholemeal. Study results conclude that the content of fructans in bread was significantly affected by the dough-making method, and that it was decreased by the use of the sourdough. In contrast, the extended fermentation time of dough failed to reduce the fructan content of the bread.

Possible role of intestinal stem cells in the pathophysiology of irritable bowel syndrome

The pathophysiology of irritable bowel syndrome (IBS) is not completely understood. However, several factors are known to play a role in pathophysiology of IBS such as genetics, diet, gut microbiota, gut endocrine cells, stress and low-grade inflammation. Understanding the pathophysiology of IBS may open the way for new treatment approaches. Low density of intestinal stem cells and low differentiation toward enteroendocrine cells has been reported recently in patients with IBS. These abnormalities are believed to be the cause of the low density of enteroendocrine cells seen in patients with IBS. Enteroendocrine cells regulate gastrointestinal motility, secretion, absorption and visceral sensitivity. Gastrointestinal dysmotility, abnormal absorption/secretion and visceral hypersensitivity are all seen in patients with IBS and haven been attributed to the low density the intestinal enteroendocrine cells in these patients. The present review conducted a literature search in Medline (PubMed) covering the last ten years until November 2019, where articles in English were included. Articles about the intestinal stem cells and their possible role in the pathophysiology of IBS are discussed in the present review. The present review discusses the assumption that intestinal stem cells play a central role in the pathophysiology of IBS and that the other factors known to contribute to the pathophysiology of IBS such as genetics, diet gut microbiota, stress, and low-grade inflammation exert their effects through affecting the intestinal stem cells. It reports further the data that support this assumption on genetics, diet, gut microbiota, stress with depletion of glutamine, and inflammation.

Nutritional status in irritable bowel syndrome: A North American population-based study

Background and Aim

Irritable bowel syndrome (IBS) affects 12% of the population, and the evidence supporting current medical interventions is poor. There is increasing focus on the therapeutic benefit of diet and supplementation. We aim to compare dietary composition and hematologic and biochemical markers in those with and without IBS to determine potential targets for therapeutic supplementation.

Methods

All 17 national surveys between 1959 and 2019 were screened, and only 1, the Second National Health and Nutrition Examination Survey (NHANES II) (1976–1980), provided comprehensive data on IBS. We performed a cross‐sectional analysis of hematologic and biochemical markers and dietary composition of 12 295 individuals, aged 18–74, in NHANES II.

Results

Individuals with IBS had significantly higher copper–zinc ratios (1.70 vs 1.55, P = 0.048) and were more likely to have ratios above 1.8 (odds ratio 1.79, 95% confidence interval 1.02–3.13), indicative of underlying copper–zinc imbalance. While more likely to report dietary avoidances, they had no other evidence of nutritional deficiencies. In addition, dietary recall showed that those with IBS consumed more calories (P = 0.02), were more likely to take vitamin supplements (P = 0.003), and that their macro and micronutrient intake was not significantly different.

Conclusions

The findings suggest that individuals with IBS should be screened for copper–zinc imbalance. Given zinc's role in the immune system, the “brain–gut” axis, and the gastrointestinal barrier, the identified copper–zinc imbalance may play a role in perpetuating the underlying pathophysiology of IBS. Further studies are needed to investigate this hypothesis and the potential role of therapeutic zinc supplementation.

Does a Minority of Children With Functional Gastrointestinal Disorders Receive Formal Diet Advice?

BACKGROUND

Diet therapies may be recommended for pediatric functional gastrointestinal disorders (FGIDs). However, little is known about the frequency with which diet therapy is recommended in FGIDs. Our aims were to determine and contrast the frequency and types of diet recommendations provided to children with FGIDs by pediatric gastroenterologists (PGIs) versus primary care pediatricians (PCPs).

METHODS

A retrospective chart review was performed using data from a large, metropolitan children's academic healthcare system to identify subjects meeting Rome IV criteria for functional abdominal pain, functional dyspepsia, irritable-bowel syndrome (IBS), and/or abdominal migraine over a period of 23 months.

RESULTS

Of 1929 patient charts reviewed, 268 were included for further analyses. Of these, 186 patients (69%) were seen by a PGI and 82 (31%) by a PCP. The most common diagnosis was IBS (49% for PGIs and 71% for PCPs). Diet recommendations were provided to 115 (43%) patients (PGI group: 86 [75%] vs PCP group: 29 [25%]; P < .1). The most frequent recommendations were high fiber (PGI: 15%; PCP: 14%) and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) diet (PGI: 12%; PCP: 4%). Of those provided with diet recommendations, only 20% (n = 23) received an educational consult by a dietitian. Provision of diet recommendations was not affected by years in practice.

CONCLUSION

Despite increasing awareness of the role of diet in the treatment of childhood FGIDs, a minority of patients receive diet recommendations in tertiary care or primary care settings. When diet recommendations were given, there was great variability in the guidance provided.

Possible role of peptide YY (PYY) in the pathophysiology of irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder of unknown aetiology for which there is no effective treatment. Although IBS does not increase mortality, it reduces the quality of life and is an economic burden to both the patients themselves and society as a whole. Peptide YY (PYY) is localized in endocrine cells located in the ileum, colon and rectum. The concentration of PYY and the density of PYY cells are decreased in both the colon and rectum but unchanged in the ileum of patients with IBS. The low density of PYY cells in the large intestine may be caused by a decreased number of stem cells and their progeny toward endocrine cells. PYY regulates the intestinal motility, secretion and absorption as well as visceral sensitivity via modulating serotonin release. An abnormality in PYY may therefore contribute to the intestinal dysmotility and visceral hypersensitivity seen in IBS patients. Diet management involving consuming a low-FODMAP diet restores the density of PYY cells in the large intestine and improves abdominal symptoms in patients with IBS. This review shows that diet management appears to be a valuable tool for correcting the PYY abnormalities in the large intestine of IBS patients in the clinic.

Adherence to the pro-inflammatory diet in relation to prevalence of irritable bowel syndrome

Objective

There is no prior study that examined the association between nutrient-based dietary inflammatory index (DII) and odds of Irritable Bowel Syndrome (IBS). We examined the association between DII score and odds of IBS and its severity among Iranian adults.

Methods

In this cross-sectional study, dietary intakes of 3363 Iranian adults were examined using a validated Dish-based 106-item Semi-quantitative Food Frequency Questionnaire (DS-FFQ). DII was calculated based on dietary intakes derived from DS-FFQ. IBS was assessed using a modified Persian version of Rome III questionnaire.

Results

After adjustment for potential confounders, we found that participants in the highest quintile of DII score had greater chance for IBS compared with those in the lowest quintile (OR: 1.36; 95% CI: 1.03–1.80). By gender, we found a significant association between DII score and IBS among women (OR: 1.41; 95% CI: 1.00–2.00). By BMI status, overweight or obese (BMI ≥ 25 kg/m²) individuals in top quintile of DII score had greater odds for IBS than those in the bottom quintile (OR: 1.64; 95% CI: 1.07–2.53). No significant association was observed between a pro-inflammatory diet and severity of IBS symptoms.

Conclusions

Consumption of a pro-inflammatory diet was associated with increased odds of IBS, in particular among women and those with BMI ≥ 25 kg/m².

Low FODMAPs diet for functional abdominal pain disorders in children: critical review of current knowledge

OBJECTIVE

This narrative review aimed to provide practitioners a synthesis of the current knowledge on the role of a low Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols diet in reducing symptoms associated with functional abdominal pain disorders in children. This review is focused on the pathophysiology, efficacy and criticism of low Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols diet in children.

SOURCES

Cochrane Database, Pubmed and Embase were searched using specific terms for Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols diet interventions and functional abdominal pain disorders.

SUMMARY OF THE FINDINGS

In children, only one Randomized Control Trial and one open-label study reported positive results of low Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols diet; one Randomized Control Trial showed exacerbation of symptoms with fructans in children with Irritable Bowel Syndrome; no effect was found for the lactose-free diet whilst fructose-restricted diets were effective in 5/6 studies.

CONCLUSIONS

In children there are few trials evaluating low Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols in functional abdominal pain disorders, with encouraging data on the therapeutic efficacy particularly of fructose-restricted diet. Additional efforts are still needed to fill this research gap and clarify the most efficient way for tailoring dietary restrictions based on the patient's tolerance and/or identification of potential biomarkers of low Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols efficacy, to maintain nutritional adequacy and to simplify the adherence to diet by labeling Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols content in commercial products.

Chain length of dietary fatty acids determines gastrointestinal motility and visceromotor function in mice in a fatty acid binding protein 4-dependent manner

Purpose

We hypothesize that different types of dietary fatty acids (FAs) affect gastrointestinal (GI) motility and visceromotor function and that this effect can be regulated by the fatty acid binding protein 4 (FABP4).

Methods

Mice were fed for 60 days with standard diet (STD), STD with 7% (by weight) coconut oil, rich in medium-chain FAs (MCFAs) (COCO), or with 7% evening primrose oil, rich in long-chain FAs (LCFAs) (EPO). In each group, half of the mice received FABP4 inhibitor, BMS309403 (1 mg/kg; i.p.) twice a week. Body weight (BW) and food intake were measured; well-established tests were performed to characterize the changes in GI motility and visceral pain. White adipose tissue and colonic samples were collected for cell culturing and molecular studies.

Results

COCO significantly increased GI transit, but not colonic motility. COCO and EPO delayed the onset of diarrhea, but none affected the effect of loperamide. EPO reduced BW and increased the visceromotor response (VMR) to colorectal distension (CRD). COCO and EPO reduced differentiation of preadipocytes. Treatment with BMS309403: (1) reversed the effects induced by COCO in physiological conditions and in mouse models of diarrhea; (2) prevented the effects of EPO on BW, VMR to CRD and castor oil-induced diarrhea; (3) affected proliferation of preadipocytes; (4) changed the expression of Fabp4 in colonic and adipocyte samples from COCO and EPO.

Conclusion

Modifying dietary intake of MCFAs and LCFAs may be used to control GI motility or visceral pain and thus modulate the symptoms of functional GI disorders. The effect is dependent on the expression of FABP4.

Electronic supplementary material

The online version of this article (10.1007/s00394-019-02094-2) contains supplementary material, which is available to authorized users.

Diet in Irritable Bowel Syndrome (IBS): Interaction with Gut Microbiota and Gut Hormones

Diet plays an important role not only in the pathophysiology of irritable bowel syndrome (IBS), but also as a tool that improves symptoms and quality of life. The effects of diet seem to be a result of an interaction with the gut bacteria and the gut endocrine cells. The density of gut endocrine cells is low in IBS patients, and it is believed that this abnormality is the direct cause of the symptoms seen in IBS patients. The low density of gut endocrine cells is probably caused by a low number of stem cells and low differentiation progeny toward endocrine cells. A low fermentable oligo-, di-, monosaccharide, and polyol (FODMAP) diet and fecal microbiota transplantation (FMT) restore the gut endocrine cells to the level of healthy subjects. It has been suggested that our diet acts as a prebiotic that favors the growth of a certain types of bacteria. Diet also acts as a substrate for gut bacteria fermentation, which results in several by-products. These by-products might act on the stem cells in such a way that the gut stem cells decrease, and consequently, endocrine cell numbers decrease. Changing to a low-FODMAP diet or changing the gut bacteria through FMT improves IBS symptoms and restores the density of endocrine cells.

The Role of Dietary Energy and Macronutrients Intake in Prevalence of Irritable Bowel Syndromes

Background

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain and altered bowel habits in the absence of any detectable organic illnesses. Interest in the effect of dietary opponents to the IBS pathogenesis has been increased in recent years. This study aims to review previous studies to determine the relationship between IBS prevalence in community and dietary energy and macronutrients intakes according to the national nutrition surveys.

Methods

A literature search was conducted in PubMed and EMBASE to September, 2018, to identify population-based studies that reported the prevalence of IBS. Daily energy intake, daily carbohydrates, and protein and fat percent contribution to energy intake (%) were obtained from study population-based national nutrition survey. The correlations of prevalence of IBS and dietary intakes were obtained by Spearman coefficient or Pearson coefficient.

Results

Global prevalence of IBS was 11.7%. There was no correlation between overall prevalence of IBS of individual countries and national energy intake (P = 0.785), protein proportion (P = 0.063), carbohydrates proportion (P = 0.505), or fat proportion (P = 0.384) according to the years when the studies were conducted. No correlations were detected between dietary intake and male or female IBS prevalence. Interestingly, protein proportion was positively correlated with the prevalence of IBS in Rome III criteria (r = 0.569).

Conclusion

Our findings demonstrate that dietary energy and macronutrients intake do not play a direct role in prevalence of IBS. However, IBS diagnostic criteria seem to have a bias on the correlation between prevalence of IBS and dietary intake. Further studies are needed to confirm the correlation between prevalence of IBS and specific dietary intake.

IRRITABLE BOWEL SYNDROME, FOOD INTOLERANCE AND NON- CELIAC GLUTEN SENSITIVITY. A NEW CLINICAL CHALLENGE

Approximately 80% of irritable bowel syndrome (IBS) patients report that their symptoms are triggered after ingesting one or specific food groups. Gluten, wheat and related proteins (e.g., amylase-trypsin inhibitors, and fermentable oligo-di-mono-saccharides and polyols (FODMAPs) are the most relevant IBS symptom triggers, although the true 'culprit(s)' is/are still not well established. The concept of causal relationship between gluten intake and the occurrence of symptoms in the absence of celiac disease and wheat allergy was termed non-celiac gluten sensitivity (NCGS). The borderline between celiac disease, wheat allergy, IBS and NCGS is not always clearly distinguishable, and the frequency and clinical identity of NGCS are still unclear. An overlap between IBS and NCGS has been detected. The incomplete knowledge of the etiopathogenesis of these clinical conditions, lack of data on their real epidemiology, as well as the absence of a gold standard for their diagnosis, make the overall picture difficult to understand "It is crucial to well define the interaction between IBS, food intolerance and NGCS, since the role of diet in IBS and its dietary management is an essential tool in the treatment of a large number of these patients". The objective of the present review is to provide an overview highlighting the interaction between IBS, food intolerance and NCGS in order to unravel whether gluten/wheat/FODMAP sensitivity represents 'facts' and not 'fiction' in IBS symptoms.

Empirically derived food-based inflammatory potential of the diet, irritable bowel syndrome, and its severity

OBJECTIVE

To our knowledge, no studies have examined the association between the empirically derived food-based dietary inflammatory index (FDII) and irritable bowel syndrome (IBS). The aim of this study was to examine the relationship between the FDII score and IBS in a large sample of Iranian adults.

METHODS

In this cross-sectional study, the dietary intakes of 3363 adults were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). The FDII was calculated based on the dietary intakes of food groups derived from DS-FFQ. IBS was assessed using a modified Persian version of the Rome III questionnaire.

RESULTS

Participants in the top quintile of the FDII score had a 42% greater risk for IBS than those in the bottom quintile (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.08-1.88). Among women, we observed a significant direct association between the FDII score and IBS after adjustment for potential confounders (OR, 1.44; 95% CI, 1.01-2.04). By body mass index (BMI) status, normal weight subjects (BMI <25 kg/m²) in the top quintile of the FDII score had higher risk for IBS (OR, 1.60; 95% CI, 1.07-2.35) than those in the bottom quintile. These associations were not observed in men or in participants with a BMI ≥25 kg/m². There was no significant association between the FDII score and IBS subtypes. No significant association between the FDII score and IBS severity was observed.

CONCLUSIONS

Consumption of a pro-inflammatory diet was associated with increased risk for IBS, especially in women and in individuals with a BMI <25 kg/m².

Influence of Dietary Restriction on Irritable Bowel Syndrome

Up to two-thirds of patients with IBS attribute their gastrointestinal symptoms to food. The therapeutic focus of IBS has been to alleviate gastrointestinal symptoms, approached by pharmaceutical and non-pharmaceutical treatments. Although the most traditional approach has involved the use of medications such as bulking agents, anticholinergics, antispasmodics, and antidiarrheals, unfortunately these are only modestly effective and patients are left with a small menu of successful pharmacologic agents. These treatments, however, are not always enough to alleviate symptoms. Alternative approaches have therefore been tried, including dietary manipulation. This article aims to review dietary restrictions as a non-pharmaceutical management approach for IBS, covering literature on various dietary triggers and the impact of dietary manipulation on gastrointestinal symptoms.

Effect of a short-term low fermentable oligiosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms

BACKGROUND

Research has demonstrated that low fermentable oligiosaccharide, disaccharide, monosaccharide and polyol (FODMAP) diets improve gastrointestinal (GI) symptoms in irritable bowel syndrome sufferers. Exercise-related GI issues are a common cause of underperformance, with current evidence focusing on the use of FODMAP approaches with recreationally competitive or highly trained athletes. However, there is a paucity of research exploring the potential benefit of FODMAP strategies to support healthy, recreational athletes who experience GI  issues during training. This study therefore aimed to assess whether a short-term LOWFODMAP diet improved exercise-related GI symptoms and the perceived ability to exercise in recreational runners.

METHODS

Sixteen healthy volunteers were randomly assigned in a crossover design manner to either a LOWFODMAP (16.06 ± 1.79 g·d- 1) or HIGHFODMAP (38.65 ± 6.66 g·d- 1) diet for 7 days, with a one week washout period followed by a further 7 days on the alternate diet. Participants rated their gastrointestinal symptoms on an adapted version of the Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) questionnaire before and at the end of each dietary period. Perceived ability to exercise (frequency, intensity and duration) in relation to each dietary period was also rated using a visual analogue scale. Resting blood samples were collected prior to and on completion of each diet to determine plasma intestinal fatty acid binding protein (I-FABP) as a marker of acute GI injury.

RESULTS

Overall IBS-SSS score significantly reduced in the LOWFODMAP condition from 81.1 ± 16.4 to 31.3 ± 9.2 (arbitrary units; P = 0.004). Perceived exercise frequency (z = 2.309, P = 0.02) and intensity (z = 2.687, P = 0.007) was significantly improved following a short-term LOWFODMAP approach compared to HIGHFODMAP. No significant differences were reported between dietary conditions for plasma I-FABP (P > 0.05).

CONCLUSIONS

A short-term LOWFODMAP diet under free-living conditions reduced exercise-related GI symptoms and improved the perceived ability to exercise in otherwise healthy, recreational runners. These findings may be explained by a reduction in indigestible carbohydrates available for fermentation in the gut. The therapeutic benefits of LOWFODMAP diets in recreational and trained athletes during sustained training periods warrants further investigation.

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

Background

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

Aims

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

Methods

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

Results

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

Conclusions

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

Fecal microbiota transplantation for managing irritable bowel syndrome

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

Habitual diet and diet quality in Irritable Bowel Syndrome: A case-control study

BACKGROUND

Diet is considered to be a key factor in symptom generation in Irritable Bowel Syndrome (IBS) and patients tend to exclude food products from their diet in pursue of symptom relief, which may impair diet quality.

METHODS

We evaluated habitual dietary intake in IBS patients with regard to nutrients and food products using an extensive food frequency questionnaire. One hundred ninety-four IBS patients were compared to 186 healthy controls using multiple logistic regression analysis. An overall diet quality score was calculated for each participant based on the criteria of the Dutch Healthy Diet (DHD) index.

KEY RESULTS

A lower DHD-score was found for IBS (mean [SD]: 52.9 [9.6]) vs controls (55.1 [9.2], P=.02). The diet of patients was lower in fibers (21 g vs 25 g per day, P=.002) and fructose (14 g vs 16 g, P=.033), while higher in total fat (37% vs 36% of total energy intake, P=.010) and added sugars (46 g vs 44 g, P=.029). Differences in daily intake of food products included lower consumption of apples (40 g vs 69 g, P<.001), pasta (28 vs 37 g, P=.029) and alcoholic beverages (130 g vs 193 g, P=.024) and higher consumption of processed meat (38 g vs 29 g, P<.001). Some of these findings correlated with gastrointestinal symptoms, showing differences between IBS subtypes.

CONCLUSIONS AND INFERENCES

Differences in habitual diet were described, showing lower diet quality in IBS patients compared to controls, with increased consumption of fat and lower intake of fibers and fructose. Our data support the importance of personalized and professional nutritional guidance of IBS patients.

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

OBJECTIVES

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

METHOD AND MATERIALS

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

RESULTS

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

CONCLUSION

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

Association between self-reported vegetarian diet and the irritable bowel syndrome in the French NutriNet cohort

BACKGROUND

There is growing interest in using diet counselling in the management of patients with irritable bowel syndrome (IBS). Among new emerging diets, vegetarian diets (VD) seem to be experiencing an important popularity, partly because of their alleged health benefits. A recent study performed among a rural Indian population showed that predominant VD could be associated with IBS.

OBJECTIVE

This cross-sectional study aimed at assessing the association between the VD and IBS, among a large French cohort, the NutriNet-santé study.

METHODS

Subjects participating in the NutriNet-Santé cohort study completed a questionnaire based on Rome III criteria (N = 41,682). Anthropometrics, socio-demographical and lifestyle data, including VD, were collected prior to the completion of Rome III questionnaire via self-administered questionnaires. Association between VD and IBS and its subtypes was investigated through multivariate logistic regression.

RESULTS

The included subjects were mainly women (78.0%) and the mean age was 49.8±14.3 years. Among these individuals, 2,264 (5.4%) presented an IBS, and 805 (1.9%) reported a VD. Overall, VD was not associated with IBS or subtypes. A stable VD (i.e. self-declared at least three times) was associated with IBS (aOR 2.60 95%CI [1.37-4.91]), IBS mixed (aOR 2.97 95%CI [1.20-7.36]) and IBS diarrhoea (aOR 2.77 95%CI [1.01-7.59]).

CONCLUSIONS

This study suggests that a long term VD could be associated with IBS. Nevertheless, further studies are needed to confirm these results, and investigate the multiple aspects of the vegetarian diet, possibly related to the IBS.

Effect of diet and individual dietary guidance on gastrointestinal endocrine cells in patients with irritable bowel syndrome (Review)

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal (GI) disorder that is characterized by a combination of abdominal pain or discomfort, bloating and alterations in bowel movements. This review presents recent developments concerning the roles of diet and GI endocrine cells in the pathophysiology of IBS and of individual dietary guidance in the management of IBS. Patients with IBS typically report that food aggravates their IBS symptoms. The interactions between specific types of foodstuffs rich in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) and GI endocrine cells induce changes in cell densities. Providing individual dietary guidance about a low FODMAP intake, high soluble-fiber intake, and changing the proportions of protein, fat and carbohydrates helps to reduce the symptoms experienced by patients with IBS and to improve their quality of life. These improvements are due to restoring the densities of the GI endocrine cells back to normal. The reported observations emphasize the role of GI endocrine cells in the pathophysiology of IBS and support the provision of dietary guidance as a first-line treatment for managing IBS.

Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients!

A substantial proportion of patients with irritable bowel syndrome (IBS) associate their symptoms with the ingestion of specific foods. Therefore, in recent years, scientific research has increasingly focused on the role of diet in IBS and dietary management is now considered an important tool in IBS treatment. This article reviews the main dietary approaches in IBS emphasizing evidence from experimental and observational studies and summarizing the main diet and lifestyle recommendations provided by dietary guidelines and scientific literature. Despite the limited evidence for a beneficial role, general advice on healthy eating and lifestyle is recommended as the first-line approach in the dietary management of IBS. Standard recommendations include adhering to a regular meal pattern, reducing intake of insoluble fibers, alcohol, caffeine, spicy foods, and fat, as well as performing regular physical activity and ensuring a good hydration. Second-line dietary approach should be considered where IBS symptoms persist and recommendations include following a low FODMAP diet, to be delivered only by a healthcare professional with expertise in dietary management. The efficacy of this diet is supported by a growing body of evidence. In contrast, the role of lactose or gluten dietary restriction in the treatment of IBS remains subject to ongoing research with a lack of high-quality evidence. Likewise, further clinical trials are needed to conclude the efficacy of probiotics on IBS symptoms.