Irritable bowel syndrome: role of food in pathogenesis and management

Prevalence and determinants of postprandial diarrhea in a tertiary care center

BACKGROUND AND AIMS

Postprandial diarrhea (PPD) is commonly seen in patients with disorders of gut-brain interaction (DGBI), but the factors associated with it have not been well studied. In this study, we aim to study the burden, impact, and predictors of PPD using a clinical cohort of DGBI patients.

METHODS

This study included patients with chronic diarrhea fulfilling ROME IV criteria for irritable bowel syndrome (IBS) or functional diarrhea (FDiarr). PPD was defined as patients reporting mushy/watery stools following meals ≥30% of the time in the last 3 months using a ROME IV question on PPD. Age, sex, and BMI, the severity of diarrhea, abdominal pain, depression, anxiety, somatization, and quality of life were assessed using validated measures. Person's chi-square test and Student's t-test were used to compare variables. A multiple linear regression model with backward elimination was done to determine predictors of PPD severity.

KEY RESULTS

Of 213 eligible patients, more than three-fourth of patients (75.6%) had PPD. Women (79.0%, p = 0.037), patients with ROME IV diagnosis of IBS-D (90.5%, p = 0.002), and functional dyspepsia (83.2%, p = 0.014), and those with a history of cholecystectomy (CCY) (95.5%, p = 0.022) were more likely to report PPD. PPD patients experienced more severe abdominal pain, diarrhea, and decreased quality of life (QoL) but showed no significant difference in BMI, anxiety, depression, sleep, or somatization. In our regression model, female sex and history of CCY were independent predictors of PPD.

CONCLUSIONS AND INFERENCES

PPD is frequently reported among chronic diarrhea patients and is associated with more severe GI symptoms and decreased QoL. Female sex and CCY predict PPD, while psychological factors do not.

Divergent effects of exendin-4 and interleukin-6 on rat colonic secretory and contractile activity are associated with changes in regional vagal afferent signaling

BACKGROUND

The pro-inflammatory cytokine, interleukin (IL)-6 is elevated in individuals with the functional bowel disorder, irritable bowel syndrome (IBS). IL-6 can independently modify intestinal secreto-motor function, thereby contributing to IBS pathophysiology. Additionally, hormonal changes may underlie symptom flares. Post-prandial exacerbation of IBS symptoms has been linked to secretion of the incretin hormone, glucagon-like peptide-1 (GLP-1), which can also influence colonic secreto-motor activity. This study aimed to ascertain if the effects of GLP-1 on colonic secretory and contractile activity was impacted by elevated IL-6 levels and if sensory signals regarding such changes were reflected in altered vagal afferent activity.

METHODS

Colonic secretory currents and circular muscle contractile activity was investigated in Sprague Dawley rats using Ussing chamber and organ bath electrophysiology. Regional afferent signaling was assessed using extracellular electrophysiological recordings from colonic vagal afferents.

KEY RESULTS

Application of the GLP-1 receptor agonist, exendin-4 (Ex-4) in the presence of IL-6 potentiated colonic secretory currents and transepithelial resistance. Vagal afferent fibers originating in the submucosal layer exhibited larger responses to Ex-4 when IL-6 was also present. In contrast, co-application of Ex-4 and IL-6 to gut-bath chambers suppressed circular muscle contractile activity. The activity in extrinsic afferents originating in the colonic myenteric layer was similarly suppressed.

CONCLUSIONS & INFERENCES

Application of Ex-4 in the presence of IL-6 had divergent modulatory effects on colonic secretion and contractile activity. Similar patterns were observed in vagal afferent signaling originating in the submucosal and myenteric neuronal layers, indicating regional afferent activity reflected immune- and endocrine-mediated changes in colonic function.

Long-Term Effect of a Gluten-Free Diet on Diarrhoea- or Bloating-Predominant Functional Bowel Disease: Role of the 'Low-Grade Coeliac Score' and the 'Coeliac Lymphogram' in the Response Rate to the Diet

1.

BACKGROUND

The long-term effect of a gluten-free diet (GFD) on functional bowel disorders (FBDs) has been scarcely studied. The aim was to assess the effect of a GFD on FBD patients, and to assess the role of both the low-grade coeliac score and coeliac lymphogram in the probability of response to a GFD. 2.

METHODS

116 adult patients with either predominant diarrhoea or abdominal bloating, fulfilling Rome IV criteria of FBD, were treated with a GFD. Duodenum biopsies were performed for both pathology studies and intraepithelial lymphocyte subpopulation patterns. Coeliac lymphogram was defined as an increase in TCRγδ+ cells plus a decrease in CD3- cells. A low-grade coeliac score >10 was considered positive. 3.

RESULTS

Sustained response to GFD was observed in 72 patients (62%) after a median of 21 months of follow-up, who presented more often with coeliac lymphogram (37.5 vs. 11.4%; p = 0.02) and a score >10 (32 vs. 11.4%; p = 0.027) compared to non-responders. The frequency of low-grade coeliac enteropathy was 19.8%. 4.

CONCLUSION

A GFD is effective in the long-term treatment of patients with previously unexplained chronic watery diarrhoea- or bloating-predominant symptoms fulfilling the criteria of FBD. The response rate was much higher in the subgroup of patients defined by the presence of both a positive low-grade coeliac score and coeliac lymphogram.

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

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

Efficacy and Safety of Probiotics in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Background

Irritable bowel syndrome is a functional gastrointestinal disease. Evidence has suggested that probiotics may benefit IBS symptoms. However, clinical trials remain conflicting.

Aims

To implement a systematic review and meta-analysis of clinical trials regarding the efficacy and safety of probiotics for IBS patients.

Methods

We searched for relevant trials in Medline(1966 to Jan 2019), Embase(1974 to Jan 2019), the Cochrane Central Register of Controlled Trials(up to Jan 2019), the ClinicalTrials.gov trials register(up to Jan 2019), and Chinese Biomedical Literature Database(1978 to Jan 2019). Risk ratio (RR) and a 95% confidence interval (CI) were calculated for dichotomous outcomes. Standardized mean difference (SMD) and 95% CI were calculated for continuous outcomes.

Results

A total of 59 studies, including 6,761 patients, were obtained. The RR of the improvement or response with probiotics versus placebo was 1.52 (95% CI 1.32-1.76), with significant heterogeneity (I² = 71%, P < 0.001). The SMD of Probiotics in improving global IBS symptoms vs. Placebo was -1.8(95% CI -0.30 to -0.06), with significant heterogeneity (I² = 65%, P < 0.001). It was impossible to draw a determinate conclusion. However, there were differences in subgroup analyses of probiotics type, dose, treatment duration, and geographic position. Probiotics seem to be safe by the analysis of adverse events(RR = 1.07; 95% CI 0.92-1.24; I² = 0, P = 0.83).

Conclusion

Probiotics are effective and safe for IBS patients. Single probiotics with a higher dose (daily dose of probiotics ≥10¹⁰) and shorter duration (< 8 weeks) seem to be a better choice, but it still needs more trials to prove it.

The Glucagon-like peptide-1 receptor agonist, exendin-4, ameliorated gastrointestinal dysfunction in the Wistar Kyoto rat model of Irritable Bowel Syndrome

BACKGROUND

Glucagon-like peptide-1 (GLP-1) is beneficial in relieving pain-related symptoms of Irritable bowel syndrome (IBS), a prevalent, multi-factorial functional bowel disorder characterized by diarrhea and/or constipation, abdominal bloating, and pain. Activation of myenteric neurons has been implicated in the inhibitory effects of GLP-1 on gastrointestinal motility; however, the mechanisms of action underlying this are not clear.

METHODS

A rat model of IBS was used to examine physiological changes evoked by intraperitoneal administration of a GLP-1 receptor agonist, exendin-4. Behavioral and physiological analysis of stress-sensitive Wister Kyoto (WKY) rats was used to determine if administration of exendin-4, in the presence or absence of neutralizing interleukin-6 receptor monoclonal antibodies, modified IBS-like symptoms. Immunofluorescence, calcium imaging, and Western blotting techniques were used to investigate the potential role of enteric neural plexi and tight junction protein expression in this effect.

KEY RESULTS

Consistent with the expression of GLP-1 and interleukin-6 receptors in both submucosal and myenteric ganglia, exendin-4 and interleukin-6 stimulated calcium responses in these neurons. In vivo administration of exendin-4 normalized stress-induced defecation and visceral pain sensitivity in WKY rats. No additional changes were noted in rats co-treated with exendin-4 and anti-interleukin-6 receptor antibodies. Mucosal expression of occludin, a tight junction protein, was decreased by exendin-4. Centrally regulated anxiety-like behaviors were not modified.

CONCLUSIONS AND INFERENCES

These data suggest that intraperitoneal injection of exendin-4 improves bowel dysfunction in WKY rats without impacting on centrally regulated anxiety-like behaviors. Modulation of enteric neuronal function and tight junction expression appear to underlie the functional benefits of this intervention.

GHSR-1 agonist sensitizes rat colonic intrinsic and extrinsic neurons to exendin-4: A role in the manifestation of postprandial gastrointestinal symptoms in irritable bowel syndrome?

BACKGROUND

Patients with irritable bowel syndrome (IBS) may experience postprandial symptom exacerbation. Nutrients stimulate intestinal release of glucagon-like peptide 1 (GLP-1), an incretin hormone with known gastrointestinal effects. However, prior to the postprandial rise in GLP-1, levels of the hunger hormone, ghrelin, peak. The aims of this study were to determine if ghrelin sensitizes colonic intrinsic and extrinsic neurons to the stimulatory actions of a GLP-1 receptor agonist, and if this differs in a rat model of IBS.

METHODS

Calcium imaging of enteric neurons was compared between Sprague Dawley and Wistar Kyoto rats. Colonic contractile activity and vagal nerve recordings were also compared between strains.

KEY RESULTS

Circulating GLP-1 concentrations differ between IBS subtypes. Mechanistically, we have provided evidence that calcium responses evoked by exendin-4, a GLP-1 receptor agonist, are potentiated by a ghrelin receptor (GHSR-1) agonist, in both submucosal and myenteric neurons. Although basal patterns of colonic contractility varied between Sprague Dawley and Wister Kyoto rats, the capacity of exendin-4 to alter smooth muscle function was modified by a GHSR-1 agonist in both strains. Gut-brain signaling via GLP-1-mediated activation of vagal afferents was also potentiated by the GHSR-1 agonist.

CONCLUSIONS & INFERENCES

These findings support a temporal interaction between ghrelin and GLP-1, where the preprandial peak in ghrelin may temporarily sensitize colonic intrinsic and extrinsic neurons to the neurostimulatory actions of GLP-1. While the sensitizing effects of the GHSR-1 agonist were identified in both rat strains, in the rat model of IBS, underlying contractile activity was aberrant.

PI 3-kinase- and ERK-MAPK-dependent mechanisms underlie Glucagon-Like Peptide-1-mediated activation of Sprague Dawley colonic myenteric neurons

BACKGROUND

Glucagon-like peptide (GLP-1) can modify colonic function, with beneficial effects reported in the functional bowel disorder, irritable bowel syndrome (IBS). IBS pathophysiology is characterized by hyper-activation of the hypothalamic-pituitary-adrenal stress axis and altered microbial profiles. This study aims to characterize the neuronal and functional effects of GLP-1 in healthy rat colons to aid understanding of its beneficial effects in moderating bowel dysfunction.

METHODS

Immunofluorescent and calcium imaging of myenteric neurons prepared from Sprague Dawley rat colons was carried out to elucidate the neuromodulatory actions of the GLP-1 receptor agonist, exendin-4 (Ex-4). Colonic contractile activity was assessed using organ bath physiological recordings.

KEY RESULTS

Ex-4 induced an elevation of intracellular calcium arising from store release and influx via voltage-gated calcium channels. Ex-4 activated both ERK-MAPK and PI 3-kinase signaling cascades. Neuronal activation was found to underlie suppression of contractile activity in colonic circular muscle. Although the stress hormone, corticotropin-releasing factor (CRF) potentiated the neuronal response to Ex-4, and the functional effects of Ex-4 on colonic circular muscle activity were not altered.

CONCLUSIONS AND INFERENCES

Ex-4 evoked neurally regulated suppression of rat colonic circular muscle activity. In myenteric neurons, the neurostimulatory effects of Ex-4 were dependent upon activation of PI 3-kinase and ERK-MAPK signaling cascades. No further change in circular muscle function was noted in the presence of CRF suggesting that stress does not impact on colonic function in health. Further studies in a model of IBS are needed to determine whether mechanisms are modified in the context of bowel dysfunction.

How Patients with IBS Use Low FODMAP Dietary Information Provided by General Practitioners and Gastroenterologists: A Qualitative Study

There is a lack of dietitians trained to deliver the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (LFD) for irritable bowel syndrome (IBS). Many patients receive nutritional information from general practitioners (GPs) or gastroenterologists (GEs). Since the LFD is dietitian-led, the aim of this research was to qualitatively explore the effects of GP- and GE-delivered LFD information, in IBS self-management. Semi-structured interviews were conducted in a purposive sample of 8 people with IBS (6 female), who used the LFD as their primary treatment. Interpretive Phenomenological Analysis (IPA) was used to develop themes on the lived experience of the participant’s use of LFD information from GPs and GEs. This information was perceived as trustworthy but simplistic; often just ”food lists” with little personalisation to meet individual needs and difficult to apply in ”real life”. The information required substantial interpretation and the familial and social effects of implementation were not addressed in the materials provided. Supplementary digital resources were regarded as more practical but the participants expressed concern in relation to the validity of these materials. The findings in this study support current clinical guidelines proposed by both the National Institute for Health and Care Excellence and the British Dietetic Association that the LFD should be considered a dietitian-led only intervention.

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 is underdiagnosed and ineffectively managed among endurance athletes

Lower gastrointestinal (GI) symptoms are common among endurance athletes and can impair performance. Symptom characteristics are similar to irritable bowel syndrome (IBS). No previous research has examined IBS diagnosis (medically or by diagnostic criteria) within this population. The objectives of this study were to determine the prevalence of IBS among endurance athletes and examine their GI symptom management strategies. A previously validated, online questionnaire assessed IBS diagnosis, the meeting of IBS diagnostic criteria (Rome III or Manning), general GI symptoms, and symptom mitigation strategies of endurance athletes. The questionnaire was distributed to United States athletes completing a marathon, ultra-marathon, half-distance triathlon, or full-distance triathlon. Medically diagnosed IBS was reported by 2.8% of endurance athletes. The total prevalence of IBS (n = 430) was 9.8% (medical diagnosis and Rome III). Athletes with IBS experienced more frequent symptoms during exercise as well as at rest; however, only 47.6% had consulted a medical professional. Over 56% of athletes experienced at least 1 symptom sometimes, often, or always during training and competition and 18.6% had symptoms that sometimes or often interrupted/prevented training. Almost half (45.8%) of athletes and 80.0% of athletes with IBS reported trying nutritional modifications to help ease symptoms while 20.6% and 52.4% used over-the-counter medications, respectively. Novelty Most endurance athletes who suffer from IBS are undiagnosed, while even more experience GI symptoms but do not fit diagnostic criteria. Despite using various symptom management methods, endurance athletes are still experiencing symptoms and could potentially benefit from current IBS-mitigating strategies.

Endocrine regulation of gut function - a role for glucagon-like peptide-1 in the pathophysiology of irritable bowel syndrome

NEW FINDINGS

What is the topic of this review? Pathophysiological changes linked to irritable bowel syndrome (IBS) include stress and immune activation, changes in gastrointestinal microbial and bile acid profiles and sensitization of extrinsic and intrinsic gut neurons. This review explores the potential role for L-cells in these pathophysiological changes. What advances does it highlight? L-cells, which secrete glucagon-like peptide-1 in response to nutrients, microbial factors, bile acids and short-chain fatty acids, may sense IBS-related changes in the luminal environment. Glucagon-like peptide-1 can act as a hormone, a paracrine factor or a neuromodulatory factor and, through its actions on central or peripheral neurons, may play a role in gastrointestinal dysfunction.

ABSTRACT

The prevalent and debilitating functional bowel disorder, irritable bowel syndrome (IBS), is characterized by symptoms that include abdominal pain, bloating, diarrhoea and/or constipation. The heterogeneity of IBS underscores a complex multifactorial pathophysiology, which is not completely understood but involves dysfunction of the bi-directional signalling axis between the brain and the gut. This axis incorporates efferent and afferent branches of the autonomic nervous system, circulating endocrine hormones and immune factors, local paracrine and neurocrine factors and microbial metabolites. L-cells, which are electrically excitable biosensors embedded in the gastrointestinal epithelium, secrete glucagon-like peptide-1 (GLP-1) in response to nutrients in the small intestine. However, they appear to function in a different manner more distally in the gastrointestinal tract, where they are activated by luminal factors including short-chain fatty acids, bile acids and microbial metabolic products, all of which are altered in IBS patients. Glucagon-like peptide-1 can also interact with the hypothalamic-pituitary-adrenal stress axis and the immune system, both of which are activated in IBS. Given that a GLP-1 mimetic has been found to alleviate acute pain symptoms in IBS patients, GLP-1 might be important in the manifestation of IBS symptoms. This review assesses the current knowledge about the role of GLP-1 in IBS pathophysiology and its potential role as a signal transducer in the microbiome-gut-brain signalling axis.

Cow's Milk Protein Allergy in Infancy: A Risk Factor for Functional Gastrointestinal Disorders in Children?

The role and prevalence of cow's milk protein allergy (CMA) in functional gastrointestinal disorders remains unclear. The aim of this review is to update knowledge on the relationship between CMA and functional abdominal pain disorders (FAPDs) in children. Cochrane Database and Pubmed were searched from inception using general and specific terms for CMA and functional gastrointestinal disorders. CMA is reported as a predisposing or coexisting factor in a wide range of functional gastrointestinal disorders in infants and children. Pathogenesis of both conditions is complex and multiple mechanisms including dysmotility and hypersensitivity might contribute to the clinical manifestations. Data supporting the possible role of food allergies in the pathogenesis of FAPDs are limited. CMA may predispose to early life inflammation and visceral hypersensitivity, which in turn might manifest as FAPDs. The diagnosis of either CMA or FAPDs and distinction between them is challenging because of nonspecific and overlapping symptoms. Lack of accurate allergy tests in non-IgE (immunoglobulin E) mediated cases is also problematic. Oral food challenge, following an elimination diet, should be performed to diagnose a suspected non-IgE CMA allergy in children with FAPDs. In the management of FAPDs, an elimination diet should be considered for a limited period to verify if the symptoms improve or resolve.

The Overlapping Area of Non-Celiac Gluten Sensitivity (NCGS) and Wheat-Sensitive Irritable Bowel Syndrome (IBS): An Update

Gluten-related disorders have recently been reclassified with an emerging scientific literature supporting the concept of non-celiac gluten sensitivity (NCGS). New research has specifically addressed prevalence, immune mechanisms, the recognition of non-immunoglobulin E (non-IgE) wheat allergy and overlap of NCGS with irritable bowel syndrome (IBS)-type symptoms. This review article will provide clinicians with an update that directly impacts on the management of a subgroup of their IBS patients whose symptoms are triggered by wheat ingestion.

A nutritional approach for managing irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder (FGID) encountered by the pediatrician and consultant. The primary focus of this review is to provide an update on beneficial nutritional interventions for managing this patient population with discussion on gut microbiome effects.

RECENT FINDINGS

A common complaint among the pediatric population is IBS-related recurrent abdominal pain. The prevalence of IBS is estimated to range between 6 and 14% and is defined by the Rome III criteria for FGIDs. Recent studies highlight the role of nutritional interventions in mitigating symptoms of IBS. Although eliminating foods that aggravate IBS gastrointestinal symptoms have become a main nutritional approach for acute management of IBS, recent literature reflects how this may impact the gut microbiome and potentially have long-term implications.

SUMMARY

There are emerging studies suggesting IBS symptomatic improvement with different dietary interventions in the pediatric population, but most of what is known at this time has been extrapolated from the adult literature.

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.

Effects of a Low FODMAP Diet and Specific Carbohydrate Diet on Symptoms and Nutritional Adequacy of Patients with Irritable Bowel Syndrome: Preliminary Results of a Single-blinded Randomized Trial

BACKGROUND AND OBJECTIVES

IBS is the most common functional disease of the low gastrointestinal tract. Recently, the interest towards a diet approach has increased, for example, a diet with low content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs). The aim of the present study is to evaluate the efficacy of a low FODMAP diet and a specific carbohydrate diet (SCD) conducted for 3 months on symptoms and to evaluate the deficiencies of vitamin D and folic acid in patients affected by IBS, matching the Rome IV criteria.

METHODS

We evaluated 73 patients divided into 2 groups: one submitted to low FODMAP diet and one to SCD, for 3 months. Patients were assigned to one of the 2 groups randomly and blinded. All the patients filled a visual analogue scale (VAS) to evaluate the severity of symptoms and a diary to evaluate the number of days with symptoms, and this was repeated after 3 months. Final evaluation was made by a blinded investigator.

RESULTS

In the end, the patients with low FODMAP diet had a significant improvement in bloating and distension (P = 0.000); the group with SCD instead had a low but not a significant improvement. One way ANOVA showed comparable severity of symptoms in the 2 groups pre-diet (P = 0.215), but a difference in the same symptoms after 12 days (P = 0.000). Tukey test showed a significant improvement in the low FODMAP diet group and only a trend of improvement in the second group of SCD. The vitamin D mean value in both groups at the time of enrollment was 38 ng/mL; in the end, the mean value in the low FODMAP diet group was 32 ng/mL and in the SCD group was 22 ng/mL, with a statistically significant difference. The folic acid mean value at the time of enrollment was 18 mg/dL; in the end, the mean value in the low FODMAP diet group was 15 mg/dL and in the SCD group was 8 mg/dL, with a statistically significant difference.

CONCLUSION

Patients affected by IBS seem to have benefitted from a low FODMAP diet but not from an SCD, and a low FODMAP diet doesn't seem to cause vitamin D and folic acid deficiencies.

Predictors of response to a low-FODMAP diet in patients with functional gastrointestinal disorders and lactose or fructose intolerance

BACKGROUND

Diets low in fermentable sugars (low-FODMAP diets) are increasingly adopted by patients with functional gastrointestinal disorders (FGID), but outcome predictors are unclear.

AIM

To identify factors predictive of an efficacious response to a low-FODMAP diet in FGID patients with fructose or lactose intolerance thereby gaining insights into underlying mechanisms.

METHODS

Fructose and lactose breath tests were performed in FGID patients to determine intolerance (positive symptom score) and malabsorption (increased hydrogen or methane concentrations). Patients with fructose or lactose intolerance consumed a low-FODMAP diet and global adequate symptom relief was assessed after 6-8 weeks and correlated with pre-diet clinical symptoms and breath test results.

RESULTS

A total of 81% of 584 patients completing the low-FODMAP diet achieved adequate relief, without significant differences between FGID subgroups or types of intolerance. Univariate analysis yielded predictive factors in fructose intolerance (chronic diarrhoea and pruritus, peak methane concentrations and fullness during breath tests) and lactose intolerance (peak hydrogen and methane concentrations and flatulence during breath tests). Using multivariate analysis, symptom relief was independently and positively predicted in fructose intolerance by chronic diarrhoea [odds ratio (95% confidence intervals): 2.62 (1.31-5.27), P = 0.007] and peak breath methane concentrations [1.53 (1.02-2.29), P = 0.042], and negatively predicted by chronic nausea [0.33 (0.16-0.67), P = 0.002]. No independent predictive factors emerged for lactose intolerance.

CONCLUSIONS

Adequate global symptom relief was achieved with a low-FODMAP diet in a large majority of functional gastrointestinal disorders patients with fructose or lactose intolerance. Independent predictors of a satisfactory dietary outcome were only seen in fructose intolerant patients, and were indicative of changes in intestinal host or microbiome metabolism.

Food regulations: low FODMAP labeling and communication goals

There is growing clinical evidence in support of a diet for irritable bowel syndrome (IBS) that is low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP). This low FODMAP diet is gaining acceptance globally among clinicians and IBS sufferers alike. However, there is disparity concerning the success rates of the FODMAP diet between patients, which can be attributed to differences in the recommended diet itself and to adherence issues. To address the differences in the diet, a generally accepted science-based definition of the analytical criteria for low FODMAP products suitable for a low FODMAP diet should be developed. To address the adherence challenge, regulators should permit manufacturers of low FODMAP products to communicate the benefits of a low FODMAP diet on product labels and promotional material which will facilitate people with IBS' selection and use low FODMAP foods.

Association between Diet and Lifestyle Habits and Irritable Bowel Syndrome: A Case-Control Study

Background/Aims

Recent papers have highlighted the role of diet and lifestyle habits in irritable bowel syndrome (IBS), but very few population-based studies have evaluated this association in developing countries. The aim of this study was to evaluate the association between diet and lifestyle habits and IBS.

Methods

A food frequency and lifestyle habits questionnaire was used to record the diet and lifestyle habits of 78 IBS subjects and 79 healthy subjects. Cross-tabulation analysis and logistic regression were used to reveal any association among lifestyle habits, eating habits, food consumption frequency, and other associated conditions.

Results

The results from logistic regression analysis indicated that IBS was associated with irregular eating (odds ratio [OR], 3.257), physical inactivity (OR, 3.588), and good quality sleep (OR, 0.132). IBS subjects ate fruit (OR, 3.082) vegetables (OR, 3.778), and legumes (OR, 2.111) and drank tea (OR, 2.221) significantly more frequently than the control subjects. After adjusting for age and sex, irregular eating (OR, 3.963), physical inactivity (OR, 6.297), eating vegetables (OR, 7.904), legumes (OR, 2.674), drinking tea (OR, 3.421) and good quality sleep (OR, 0.054) were independent predictors of IBS.

Conclusions

This study reveals a possible association between diet and lifestyle habits and IBS.

Artificial Sweeteners: A Systematic Review and Primer for Gastroenterologists

Artificial sweeteners (AS) are ubiquitous in food and beverage products, yet little is known about their effects on the gastrointestinal (GI) tract, and whether they play a role in the development of GI symptoms, especially in patients with irritable bowel syndrome. Utilizing the PubMed and Embase databases, we conducted a search for articles on individual AS and each of these terms: fermentation, absorption, and GI tract. Standard protocols for a systematic review were followed. At the end of our search, we found a total of 617 eligible papers, 26 of which were included. Overall, there is limited medical literature available on this topic. The 2 main areas on which there is data to suggest that AS affect the GI tract include motility and the gut microbiome, though human data is lacking, and most of the currently available data is derived from in vivo studies. The effect on motility is mainly indirect via increased incretin secretion, though the clinical relevance of this finding is unknown as the downstream effect on motility was not studied. The specific effects of AS on the microbiome have been conflicting and the available studies have been heterogeneous in terms of the population studied and both the AS and doses evaluated. Further research is needed to assess whether AS could be a potential cause of GI symptoms. This is especially pertinent in patients with irritable bowel syndrome, a population in whom dietary interventions are routinely utilized as a management strategy.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Diet in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder that is characterized by intermittent abdominal pain/discomfort, altered bowel habits and abdominal bloating/distension. This review aimed at presenting the recent developments concerning the role of diet in the pathophysiology and management of IBS. There is no convincing evidence that IBS patients suffer from food allergy/intolerance, and there is no evidence that gluten causes the debated new diagnosis of non-coeliac gluten sensitivity (NCGS). The component in wheat that triggers symptoms in NCGS appears to be the carbohydrates. Patients with NCGS appear to be IBS patients who are self-diagnosed and self-treated with a gluten-free diet. IBS symptoms are triggered by the consumption of the poorly absorbed fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and insoluble fibre. On reaching the distal small intestine and colon, FODMAPS and insoluble fibre increase the osmotic pressure in the large-intestine lumen and provide a substrate for bacterial fermentation, with consequent gas production, abdominal distension and abdominal pain or discomfort. Poor FODMAPS and insoluble fibres diet reduces the symptom and improve the quality of life in IBS patients. Moreover, it changes favourably the intestinal microbiota and restores the abnormalities in the gastrointestinal endocrine cells. Five gastrointestinal endocrine cell types that produce hormones regulating appetite and food intake are abnormal in IBS patients. Based on these hormonal abnormalities, one would expect that IBS patients to have increased food intake and body weight gain. However, the link between obesity and IBS is not fully studied. Individual dietary guidance for intake of poor FODMAPs and insoluble fibres diet in combination with probiotics intake and regular exercise is to be recommended for IBS patients.

Review article: the diagnosis and management of food allergy and food intolerances

BACKGROUND

Adverse reactions to food include immune mediated food allergies and non-immune mediated food intolerances. Food allergies and intolerances are often confused by health professionals, patients and the public.

AIM

To critically review the data relating to diagnosis and management of food allergy and food intolerance in adults and children.

METHODS

MEDLINE, EMBASE and the Cochrane Database were searched up until May 2014, using search terms related to food allergy and intolerance.

RESULTS

An estimated one-fifth of the population believe that they have adverse reactions to food. Estimates of true IgE-mediated food allergy vary, but in some countries it may be as prevalent as 4-7% of preschool children. The most common food allergens are cow's milk, egg, peanut, tree nuts, soy, shellfish and finned fish. Reactions vary from urticaria to anaphylaxis and death. Tolerance for many foods including milk and egg develops with age, but is far less likely with peanut allergy. Estimates of IgE-mediated food allergy in adults are closer to 1-2%. Non-IgE-mediated food allergies such as Food Protein-Induced Enterocolitis Syndrome are rarer and predominantly recognised in childhood. Eosinophilic gastrointestinal disorders including eosinophilic oesophagitis are mixed IgE- and non-IgE-mediated food allergic conditions, and are improved by dietary exclusions. By contrast food intolerances are nonspecific, and the resultant symptoms resemble other common medically unexplained complaints, often overlapping with symptoms found in functional disorders such as irritable bowel syndrome. Improved dietary treatments for the irritable bowel syndrome have recently been described.

CONCLUSIONS

Food allergies are more common in children, can be life-threatening and are distinct from food intolerances. Food intolerances may pose little risk but since functional disorders are so prevalent, greater efforts to understand adverse effects of foods in functional disorders are warranted.

Irritable bowel syndrome is positively related to metabolic syndrome: a population-based cross-sectional study

Irritable bowel syndrome is a common gastrointestinal disorder that may affect dietary pattern, food digestion, and nutrient absorption. The nutrition-related factors are closely related to metabolic syndrome, implying that irritable bowel syndrome may be a potential risk factor for metabolic syndrome. However, few epidemiological studies are available which are related to this potential link. The purpose of this study is to determine whether irritable bowel syndrome is related to metabolic syndrome among middle-aged people. We designed a cross-sectional study of 1,096 subjects to evaluate the relationship between irritable bowel syndrome and metabolic syndrome and its components. Diagnosis of irritable bowel syndrome was based on the Japanese version of the Rome III Questionnaire. Metabolic syndrome was defined according to the criteria of the American Heart Association scientific statements of 2009. Dietary consumption was assessed via a validated food frequency questionnaire. Principal-components analysis was used to derive 3 major dietary patterns: “Japanese”, “sweets-fruits”, and “Izakaya (Japanese Pub) “from 39 food groups. The prevalence of irritable bowel syndrome and metabolic syndrome were 19.4% and 14.6%, respectively. No significant relationship was found between the dietary pattern factor score tertiles and irritable bowel syndrome. After adjustment for potential confounders (including dietary pattern), the odds ratio (95% confidence interval) of having metabolic syndrome and elevated triglycerides for subjects with irritable bowel syndrome as compared with non-irritable bowel syndrome are 2.01(1.13–3.55) and 1.50(1.03–2.18), respectively. Irritable bowel syndrome is significantly related to metabolic syndrome and it components. This study is the first to show that irritable bowel syndrome was significantly related to a higher prevalence of metabolic syndrome and elevated triglycerides among an adult population. The findings suggest that the treatment of irritable bowel syndrome may be a potentially beneficial factor for the prevention of metabolic syndrome. Further study is needed to clarify this association.

Dietary Renaissance in IBS: Has Food Replaced Medications as a Primary Treatment Strategy?

OPINION STATEMENT

The medical community has only recently started to focus attention on the role of food in the pathogenesis of irritable bowel syndrome (IBS), though the association between food and gastrointestinal (GI) symptoms has been recognized by patients for decades. Health care providers receive little formal training in the dietary management of IBS and have traditionally viewed dietary interventions with skepticism. There is mounting evidence that links food to changes in motility, visceral sensation, microbiome, permeability, immune activation, and brain-gut interactions-all key elements in the pathogenesis of IBS. The role of specific dietary modification in the management of IBS has not been rigorously investigated until recently. There is now credible evidence suggesting that targeted dietary carbohydrate exclusion provides clinical benefits to IBS patients. There is emerging evidence to suggest that proteins such as gluten, as well as food chemicals, may play a role in IBS.

Food allergy testing

Food allergy (IgE-mediated hypersensitivity) is a common clinical problem affecting approximately 15% of children in the Western world. These hypersensitivity reactions tend to be "immediate" (typically within minutes of food exposure), and clinical features may range from mild to life threatening (anaphylaxis). Detailed clinical history is critical to correct diagnosis. Available laboratory tests have limitations not least poor positive predictive value and limited repertoire. Laboratory tests should support clinical diagno sis not vice versa.

What about OMT and nutrition for managing the irritable bowel syndrome? An overview and treatment plan

A chronic continuous or intermittent gastrointestinal tract dysfunction, the irritable bowel syndrome (IBS), appears to be due to dysregulation of brain-gut-microbiota communication. Furthermore, the "microbiota" greatly impacts the bi-directional brain-gut axis communication. This article describes IBS in relation to similar diseases, presents the background to osteopathy, and proposes osteopathic manipulative treatment (OMT) to manage IBS. In IBS, OMT focuses on the nervous and circulatory systems, spine, viscera, and thoracic and pelvic diaphragms in order to restore homeostatic balance, normalize autonomic activity in the intestine, promote lymphatic flow, and address somatic dysfunction. Lymphatic and venous congestion are treated by the lymphatic pump techniques and stimulation of Chapman׳s reflex points. A simple treatment plan designed to lessen chronic pain and inflammation in IBS is presented based on current evidence-based literature. Since food itself, food allergies, and intolerance could contribute to symptom onset or even cause IBS, this article also provides dietary modifications to consider for patients.

Interaction between ingested nutrients and gut endocrine cells in patients with irritable bowel syndrome (review)

Several endocrine cell abnormalities have been reported in different segments of the gastrointestinal tract of patients with irritable bowel syndrome (IBS). These cells have specialized microvilli that project into the lumen; they function as sensors for the gut contents and respond to luminal stimuli (mostly ingested nutrients) by releasing hormones into the lamina propria, where they exert their effects via a paracrine/endocrine mode of action. Certain food items trigger the symptoms experienced by IBS patients, including those rich in fermentable oligo-, di- and monosaccharides, and polyols (FODMAPs). In this review, we present the argument that the effects of both FODMAPs and the proportional intake of proteins, fats and carbohydrates on IBS symptoms may be caused by an interaction with the gut endocrine cells. Since the gut hormones control and regulate gastrointestinal motility and sensation, this interaction may be responsible for abnormal gastrointestinal motility and the visceral hypersensitivity observed in these patients. There is no consistent evidence that IBS patients suffer from food allergy. The role of gluten intolerance in the development of IBS symptoms in these patients remains a matter of controversy. Individual guidance on food management, which includes restrictions in the intake of FODMAP-rich foods and testing diets with different proportions of proteins, fats and carbohydrates has been found to reduce the symptoms, improve the quality of life, and make the habitual diet of IBS patients more healthy.

Value of food-specific IgG antibody detection in children with chronic digestive system diseases

AIM: To explore the value of food-specific IgG antibody detection in children with chronic diseases of the digestive system.

METHODS: One hundred and six children with chronic diseases of the digestive system (experiment group) and 106 children without digestive system disorders (control group) were included in this study. The IgG antibodies against 14 types of food were detected, and the positive rate of serum food-specific IgG antibody detection and feeding patterns in 4 mo after birth between the two groups were compared.

RESULTS: The positive rates of antibodies against eggs (61.32%, 18.87%) and milk (43.40%, 11.32%) were relatively high in the two groups compared with those against other food. The positive rates of antibodies against milk, eggs and soybean in the experiment group were significantly higher than those in the control group (43.40% vs 11.32%, 61.32% vs 18.87%, 11.32% vs 0.00%, P < 0.05). The percentages of subjects who were positive for antibodies against 2 or 3 kinds of food as well as the total positive rate in the experiment group were significantly higher than those in the control group (34.91% vs 13.21%, 15.09% vs 4.72%, 85.85% vs 49.06%, P < 0.05). The breast-feeding rate in 4 months after birth in the experiment group was significantly lower than that in the control group (43.40% vs 76.42%, P < 0.05). The rates of artificial feeding and partial breastfeeding in the experiment group were significantly higher than those in the control group (8.49% vs 1.89%, 48.11% vs 21.70%, P < 0.05).

CONCLUSION: Food-specific IgG detection can help identify chronic diseases of the digestive system caused by food. The antibodies against milk and eggs are the most common. Early feeding way is an important factor responsible for food intolerance.

Molecular basis of the irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional disorder characterized by abdominal pain, discomfort and bloating. The pathophysiology of IBS is poorly understood, but the presence of psychosocial basis is now known. There is an increasing number of publications supporting the role of genetics in IBS. Most of the variations are found in genes associated with the brain-gut axis, revealing the strong correlation of brain-gut axis and IBS. miRNAs, which play critical roles in physiological processes, are not well studied in IBS. However, so far there is found an involvement of alterations in miRNA expression or sequence, in IBS symptoms. IBS phenotype is affected by epigenetic alteration and environment. Changes in DNA and histone methylation are observed in patients who suffered childhood trauma or abuse, resulting in altered gene expression, such as the glucocorticoid receptor gene. Finally, diet is another factor associated with IBS, which may contribute to symptom onset. Certain foods may affect on bacterial metabolism and epigenetic modifications, predisposing to IBS.

Fructose and lactose intolerance and malabsorption testing: the relationship with symptoms in functional gastrointestinal disorders

BACKGROUND

The association of fructose and lactose intolerance and malabsorption with the symptoms of different functional gastrointestinal disorders (FGID) remains unclear.

AIM

To investigate the prevalence of fructose and lactose intolerance (symptom induction) and malabsorption and their association with clinical gastrointestinal (GI) as well as non-GI symptoms in FGID and the outcome of dietary intervention.

METHODS

Fructose and lactose intolerance (defined by positive symptom index) and malabsorption (defined by increased hydrogen/methane) were determined in 1372 FGID patients in a single centre using breath testing. Results were correlated with clinical symptoms in different FGID Rome III subgroups. The effectiveness of a targeted saccharide-reduced diet was assessed after 6-8 weeks.

RESULTS

Intolerance prevalence across all FGIDs was 60% to fructose, 51% to lactose and 33% to both. Malabsorption occurred in 45%, 32% and 16% respectively. There were no differences in intolerance or malabsorption prevalence between FGID subgroups. FGID symptoms correlated with symptoms evoked during testing (r = 0.35-0.61. P < 0.0001), but not with malabsorption. Non-GI symptoms occurred more commonly in patients with intolerances. Methane breath levels were not associated with constipation using several cut-off thresholds. Adequate symptom relief was achieved in >80% of intolerant patients, irrespective of malabsorption.

CONCLUSIONS

Fructose and lactose intolerances are common in FGID and associated with increased non-GI symptoms, but not with specific FGID subtypes. Symptoms experienced during breath testing, but not malabsorption, correlate with FGID symptoms. Effective symptom relief with dietary adaptation is not associated with malabsorption. Mechanisms relating to the generation of GI and non-GI symptoms due to lactose and fructose in FGID need to be explored further.

Current and emerging therapies for the management of functional gastrointestinal disorders

The functional gastrointestinal disorders are common disorders that are associated with significant quality-of-life impairment and considerable economic burden on the healthcare system. They are frequently associated with a comorbid psychiatric condition; this, together with a striking lack of effective pharmacological therapies, means they represent a considerable therapeutic challenge to the treating physician. In this overview, we examine the evidence to support the use of agents currently used in the management of the more common functional gastrointestinal disorders and review emerging therapies.

Bugs on the brain; brain in the gut--seeking explanations for common gastrointestinal symptoms

INTRODUCTION

Gastrointestinal symptoms such as heartburn, indigestion (or dyspepsia), bloating, distension, constipation, abdominal pain, abdominal discomfort and diarrhoea are extremely common worldwide. For some, such symptoms can prove to be chronic and disabling.

METHODS

The recent literature on irritable bowel syndrome and, in particular, work emanating form this authors research group, was reviewed.

RESULTS

These functional symptoms commonly occur in aggregations, referred to as functional gastrointestinal disorders (FGIDs). Some of the FGIDs and, most notably irritable bowel syndrome (IBS), have achieved a degree of scientific and clinical credibility as coherent entities. Several lines of evidence ranging from gut motility to the microbiota are under investigation in attempts to explain IBS or its symptomatology.

CONCLUSION

Though biomarkers for IBS and other FGIDs have proven elusive, considerable progress has been made in understanding possible aetiological factors in IBS; progress which may well lead to better therapeutic strategies.

IgG and IgG4 antibodies in subjects with irritable bowel syndrome: a case control study in the general population

BACKGROUND

Patients with Irritable Bowel Syndrome (IBS) often relate their symptoms to the intake of food and modify their diet. IgE-mediated food allergy is uncommon in IBS, but the role of IgG-mediated food hypersensitivity remains inconclusive. The primary aim of this study was to compare food- and yeast-specific IgG and IgG4 antibodies in subjects with and without IBS.

METHODS

This was a case control study in the general population for which subjects completed questionnaires about abdominal complaints and their intake of common food items. Blood samples were collected, and food- and yeast-specific IgG and IgG4 antibodies were measured. Antibodies were measured in mg/L.

RESULTS

We included 269 subjects with IBS and 277 control subjects. After correction for subject characteristics and diet, there were no significant differences with regard to food- and yeast-specific IgG and IgG4 antibodies between subjects with IBS and controls. Lower values of IgG antibodies against egg (OR 0.99 (0.98 to 1.00), p = 0.002) and beef (OR 0.75 (0.60 to 0.94), p = 0.012) and higher values of IgG antibodies against chicken (OR 1.14 (1.03 to 1.27), p = 0.009) were associated with more severe symptoms.

CONCLUSIONS

Our findings suggest that IgG-and IgG4-mediated food and yeast hypersensitivity in IBS is unlikely. IgG antibodies against food and yeast may reflect the diet.

Irritable bowel syndrome: Diagnosis and pathogenesis

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome III criteria. A combination of the Rome III criteria, a physical examination, blood tests, gastroscopy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS: heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following: genetic factors, dietary intake, intestinal flora, or low-grade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI- and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.

Relationship among food intolerance, severity of symptoms and the number of mast cells in the ileocecal junction in patients with diarrhea-predominant irritable bowel syndrome

AIM: To analyze the relationship among food intolerance, severity of symptoms and the number of mucosal mast cells (MCs) in the ileocecal junction (ICJ) in patients with diarrhea-predominant irritable bowel syndrome (D-IBS), and to explore the influence of food intolerance on the pathogenesis of D-IBS.

METHODS: Twenty-two patients with D-IBS fulfilling the Rome III criteria and 21 asymptomatic healthy controls underwent colonoscopy in which two adjacent biopsy samples were taken from the ICJ. Mucosal MCs were detected by toluidine blue staining. The Food Intolerance Questionnaire was used to evaluate the perceived food intolerance status of D-IBS patients and controls. The Functional Bowel Disorder Severity Index (FBDSI) and IBS Symptom Severity Scale (IBS-SSS) were used to evaluate the severity of symptoms in D-IBS patients. The relationship among the scores of FBDSI and IBS-SSS, the number of MCs and the scores of food intolerance in D-IBS patients was analyzed.

RESULTS: The number of mucosal MCs in the ICJ was significantly higher in patients with D-IBS than in controls (4.68 ± 0.55/HP vs 1.33 ± 0.54/HP, P < 0.001). Compared to controls, perceived FI was more frequent in patients with D-IBS (P < 0.05). The scores of FBDSI and IBS-SSS were positively correlated with that of food intolerance in D-IBS patients (FBDSI: r = 0.992, P < 0.001; IBS-SSS: r = 0.970, P < 0.001), and with the number of mucosal MCs in the ICJ (FBDSI: r = 0.957, P < 0.001; IBS-SSS: r = 0.985, P < 0.001). The scores of food intolerance in D-IBS patients were positively correlated with the number of mucosal MCs in the ICJ (r = 0.964, P < 0.001). The number of mucosal MCs in the ICJ were significantly higher in healthy subjects with self-reported food intolerance than in those without food intolerance (P < 0.05).

CONCLUSION: The symptoms of D-IBS are positively correlated with increased number of enteric mucosal MCs which might be caused by food antigen. Food intolerance is more frequent in D-IBS patients than in controls. D-IBS symptoms may be caused or exacerbated by food intolerance.

Allergic mastocytic gastroenteritis and colitis: an unexplained etiology in chronic abdominal pain and gastrointestinal dysmotility

Abdominal pain, bloating, early satiety, and changes in bowel habits are common presenting symptoms in individuals with functional GI disorders. Emerging data suggests that these symptoms may be associated with mast cell excess and/or mast cell instability in the GI tract. The aim of this retrospective study was to evaluate the contribution of mast cells to the aforementioned symptoms in individuals with a history of atopic disease. A retrospective chart review of individuals seen in a university GI practice was conducted and twenty-four subjects were identified. The majority had abdominal pain, early satiety, and nocturnal awakening. 66.7% and 37.5% had a history of environmental and/or food allergy. Solid gastric emptying was increased as were the mean number of mast cells reported on biopsies from the stomach, small bowel, and colon (>37/hpf) by CD117 staining. Mean whole blood histamine levels were uniformly elevated. This study suggests that in individuals with these characteristics, consideration should be given to staining their gastrointestinal biopsies for mast cells as this may provide them with relatively non-toxic but highly targeted treatment options. Allergic gastroenteritis and colitis may represent a third type of GI mast cell disorder along with mast cell activation syndrome and mastocytic enterocolitis.

Irritable bowel syndrome and food allergy

Irritable bowel syndrome (IBS) is a kind of functional gastrointestinal disease characterized by abdominal pain or discomfort associated with changes in bowel habits. The alternating symptoms of IBS seriously affect the patients' quality of life. Some studies have found that food could cause or aggravate the symptoms of IBS possibly by inducing food allergy and food intolerance. However, the specific mechanisms have not been established yet. Currently there are "bacterial 'toxin' hypothesis", "immune or inflammatory response hypothesis" and "physical or chemical irritation hypothesis" explaining the role of food in the pathogenesis of IBS. It has been known that food factors play a very important role in the pathogenesis of IBS. This article reviews food allergy and the possible mechanisms, diagnosis and treatment of IBS caused by food.

Complexity of case mix in a regional allergy service

BACKGROUND

Currently in the United Kingdom (UK), there is a mismatch between limited financial resources and the large proportion of patients with suspected allergies actually being referred to specialist allergy clinics. To better understand the case mix of patients being referred, we audited referrals to a regional allergy service over an 8 year period.The main source of data was consultant letters to General Practitioners (GP) summarising the diagnosis of patients, archived from January 2002 to September 2009. Letters were reviewed, extracting the clinic date, doctor seen, gender, date of birth, postcode, GP, and diagnoses. Diagnoses were classified into seven groups and illustrative cases for each group noted.

FINDINGS

Data from 2,028 new referrals with suspected allergy were analysed. The largest group of patients (43%) were diagnosed with a type I hypersensitivity. The other diagnostic groups were chronic idiopathic (spontaneous) urticaria (35%), suspected type I hypersensitivity but no allergen identified (8%), idiopathic (spontaneous) angioedema (8%), physical urticaria (2.5%), non-allergic symptoms (1.6%), type IV hypersensitivity (0.8%) and ACE inhibitor sensitivity (0.5%). Two thirds of patients seen were female with a higher percentage of female patients in the non type-I hypersensitivity group (71%) than the type 1 hypersensitivity (66%) (χ2 = 5.1, 1df, p = 0.024). The type 1 hypersensitivity patients were younger than other patients (38 Vs 46 years, t = -10.8, p < 0.001)

CONCLUSIONS

This study highlights the complexity of specialist allergy practice and the large proportion of patients referred with non-type I hypersensitivities, chronic idiopathic (spontaneous) urticaria being by far the largest group. Such information is critical to inform commissioning decisions, define referral pathways and in primary care education.

Does meal ingestion enhance sensitivity of visceroperception assessment in irritable bowel syndrome?

BACKGROUND

Visceral hypersensitivity is frequently observed in irritable bowel syndrome (IBS). Previous studies have shown that administration of a meal can aggravate symptoms or increase visceroperception in IBS patients. We investigated whether meal ingestion could increase the sensitivity of the barostat procedure for the detection of visceral hypersensitivity in IBS patients.

METHODS

Seventy-one IBS patients and 30 healthy controls (HC) were included in the study. All subjects underwent a barostat procedure under fasted and postprandial conditions to measure visceroperception. Urge, discomfort, and pain were scored on a visual analog scale. Furthermore, percentages of hypersensitive IBS patients and HC were calculated and dynamic rectal compliance was assessed.

KEY RESULTS

In IBS patients, urge, discomfort, and pain scores were significantly increased postprandially vs the fasted state. The HC showed increased scores for urge and pain only. Rectal dynamic compliance remained unaltered in both groups. Postprandial hypersensitivity percentages did not significantly differ vs the fasted state in IBS patients, nor in HC.

CONCLUSIONS & INFERENCES

Postprandial barostat measurement enhances visceroperception in IBS but has no added value to detect visceral hypersensitivity in individual IBS patients.

Does a self-management program change dietary intake in adults with irritable bowel syndrome?

Making dietary changes such as increasing fiber intake is recommended for the management of irritable bowel syndrome symptoms. Few studies have explored the efficacy of education on compliance with recommendations such as increasing fiber, vegetable, and fruit intake in adults with irritable bowel syndrome. This study examined the effect of a multicomponent self-management intervention that included strategies to enhance fiber, vegetable, and fruit intake. Participants with medically diagnosed irritable bowel syndrome were randomized to usual care or individualized comprehensive self-management, delivered either in-person or by telephone. Since previously published analyses show the two delivery modes to be equally effective, the two intervention groups were combined. Of the 188 individuals randomized, 173 participants (113 in the self-management group and 60 in the usual care group; 23 men, 150 women) provided data on at least one of the three follow-up occasions (3, 6, and 12 months postrandomization). Fiber, vegetable, and fruit intakes were measured using the Food Frequency Questionnaire. Participants in the intervention group demonstrated increases (p < .05) in fiber and fruit intake and a trend in vegetable intake at 6 and 12 months postintervention. Improvement in dietary fiber intake following a self-management intervention for IBS continues to 1 year.

Role of neuronal nitric oxide synthase in colonic distension-induced hyperalgesia in distal colon of neonatal maternal separated male rats

BACKGROUND

Nitric oxide (NO) is implicated in the pathogenesis of irritable bowel syndrome (IBS) but the underlying mechanism is unclear. Thus, the aim of the present study is to examine the role of NO synthase (NOS) expression in the distal colon of neonatal maternal separation (NMS) model rats employed in IBS studies.

METHODS

Male neonates of Sprague-Dawley rats were randomly assigned into NMS and normal control (N) groups. Rats of NMS group were subjected to 3 h daily maternal separation on postnatal day 2-21. Rats were administrated non-selective NOS inhibitor l-NAME (100 mg kg(-1) ), selective neuronal NOS (nNOS) inhibitor 7-NINA (10mgkg(-1) ), selective inducible NOS (iNOS) inhibitor, endothelial NOS (eNOS) inhibitor (10mgkg(-1) ) or Vehicle (Veh; distilled water) intraperitoneally 1h prior to the experiment for the test and control groups, respectively.

KEY RESULTS

The amount of NO was significantly higher in the NMS Veh rats compared with unseparated N rats. Western-blotting and real-time quantitative PCR studies showed that protein and mRNA expression of nNOS were higher in the NMS group than that in the N rats; whereas no significant change in iNOS and eNOS was found in either groups. Neonatal maternal separation Veh rats showed low pain threshold and increased electromyogram (EMG) activity in response to colonic distension stimuli. l-NAME and 7-Nitroindazole monosodium salt (7-NINA) increased pain threshold pressure and attenuated EMG activity in the NMS rats. In addition, l-NAME and 7-NINA substantially reduced oxidative marker malondialdehyde level in NMS rats.

CONCLUSIONS & INFERENCES

Neonatal maternal separation increased the NO generation by nNOS upregulation that interact with reactive oxygen species contributing to the visceral hypersensitivity in IBS.

Chronic idiopathic large bowel diarrhea in the dog

Chronic idiopathic large bowel diarrhea (CILBD) is a descriptive diagnosis reached by exclusion of the most common diseases associated with chronic large bowel diarrhea. The most important features of irritable bowel syndrome in people are reviewed. The authors report 19 new cases of CILBD that they compare with 37 cases from the literature. The disease appears to be common among dogs referred for colonoscopy. Many dogs with CILBD experience behavioral problems or are exposed to a stressful environment. Most dogs respond to diet change and fiber supplementation. Some benefit from behavior-modifying therapy.

Analgesic effect of Coptis chinensis rhizomes (Coptidis Rhizoma) extract on rat model of irritable bowel syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Coptis chinensis rhizomes (Coptidis Rhizoma, CR), also known as "Huang Lian", is a common component of traditional Chinese herbal formulae used for the relief of abdominal pain and diarrhea. Yet, the action mechanism of CR extract in the treatment of irritable bowel syndrome is unknown. Thus, the aim of our present study is to investigate the effect of CR extract on neonatal maternal separation (NMS)-induced visceral hyperalgesia in rats and its underlying action mechanisms.

MATERIALS AND METHODS

Male Sprague-Dawley rats were subjected to 3-h daily maternal separation from postnatal day 2 to day 21 to form the NMS group. The control group consists of unseparated normal (N) rats. From day 60, rats were administrated CR (0.3, 0.8 and 1.3 g/kg) or vehicle (Veh; 0.5% carboxymethylcellulose solution) orally for 7 days for the test and control groups, respectively.

RESULTS

Electromyogram (EMG) signals in response to colonic distension were measured with the NMS rats showing lower pain threshold and increased EMG activity than those of the unseparated (N) rats. CR dose-dependently increased pain threshold response and attenuated EMG activity in the NMS rats. An enzymatic immunoassay study showed that CR treatment significantly reduced the serotonin (5HT) concentration from the distal colon of NMS rats compared to the Veh (control) group. Real-time quantitative PCR and Western-blotting studies showed that CR treatment substantially reduced NMS induced cholecystokinin (CCK) expression compared with the Veh group.

CONCLUSIONS

These results suggest that CR extract robustly reduces visceral pain that may be mediated via the mechanism of decreasing 5HT release and CCK expression in the distal colon of rats.