Bran supplementation in the treatment of irritable bowel syndrome

A systematic review and meta-analysis of diet and nutrient intake in adults with irritable bowel syndrome

BACKGROUND

Numerous individual and environmental factors including diet may play an important role in the pathophysiology of irritable bowel syndrome (IBS). It is unclear to what degree dietary intake is affected in individuals with IBS. We aimed to perform a systematic review and meta-analysis to summarize dietary intake of adults with IBS and to compare dietary intake between adults with IBS and non-IBS controls.

METHODS

Ovid MEDLINE, Embase, Cochrane, CINAHL, and Scopus were searched through February 2023 for clinical trials and observational studies measuring usual diet in adults with IBS. Pooled weighted averages were estimated for total energy, macronutrient, and micronutrient data. Mean differences (MD) in nutrient intake were estimated for adults with IBS versus non-IBS controls using a random effects model. Heterogeneity was assessed by the inconsistency index (I2).

KEY RESULTS

Sixty-three full-text articles were included in the review of which 29 studies included both IBS and control subjects. Nutrients not meeting the recommended intake level for any dietary reference values in the IBS population were fiber and vitamin D. Meta-regression by female proportion was positively correlated with total fat intake and negatively correlated with carbohydrate intake. Comparisons between participants with IBS and controls showed significantly lower fiber intake in participants with IBS with high heterogeneity (MD: -1.8; 95% CI: -3.0, -0.6; I2 = 85%).

CONCLUSIONS AND INFERENCES

This review suggests that fiber and vitamin D intake is suboptimal in IBS; however, overall dietary intake does not appear to be comprised. Causes and consequences of reduced fiber in IBS deserve further study. Results of this systematic review and meta-analysis suggest that fiber and vitamin D intake is suboptimal in IBS. However, overall intake of other macro- and micronutrients does not appear to be compromised. Causes and consequences of reduced fiber and Vitamin D intake in IBS deserve further study.

Indian consensus statements on irritable bowel syndrome in adults: A guideline by the Indian Neurogastroenterology and Motility Association and jointly supported by the Indian Society of Gastroenterology

The Indian Neurogastroenterology and Motility Association (INMA), earlier named the Indian Motility and Functional Diseases Association developed this evidence-based practice guidelines for the management of irritable bowel syndrome (IBS). A modified Delphi process was used to develop this consensus containing 28 statements, which were concerning diagnostic criteria, epidemiology, etiopathogenesis and comorbidities, investigations, lifestyle modifications and treatments. Owing to the Coronavirus disease-19 (COVID-19) pandemic, lockdowns and mobility restrictions, web-based meetings and electronic voting were the major tools used to develop this consensus. A statement was regarded as accepted when the sum of "completely accepted" and "accepted with minor reservation" voted responses were 80% or higher. Finally, the consensus was achieved on all 28 statements. The consensus team members are of the view that this work may find use in teaching, patient care, and research on IBS in India and other nations.

How can probiotic improve irritable bowel syndrome symptoms?

The onset and manifestations of irritable bowel syndrome (IBS) is associated with several factors, and the pathophysiology involves various central and peripheral mechanisms. Most studies indicate that the management of gut microbiota could significantly affect the improvement of subjective disorders in patients with IBS. Numerous clinical trials have assessed the efficacy of probiotics for IBS with controversial conclusions. Several clinical trials have suggested that probiotics can improve global IBS symptoms, while others only improve individual IBS symptoms, such as bloating scores and abdominal pain scores. Only a few clinical trials have found no apparent effect of probiotics on IBS symptoms. Generally, probiotics appear to be safe for patients with IBS. However, the question of which probiotics should be used for certain IBS subtypes remains unresolved. In everyday practice, the dose of the recommended probiotic remains questionable, as well as how long the probiotic should be used in therapy. The use of probiotics in the M subtype and non-classified IBS is particularly problematic, in which combination therapy should be recommended due to the change in symptoms. Therefore, new approaches are needed in the design of clinical studies that should address certain subtypes of IBS.

Impact of Diet on Symptoms of the Irritable Bowel Syndrome

Irritable bowel syndrome (IBS), with its key features of abdominal pain and disturbed bowel habit, is thought by both patients and clinicians to be strongly influenced by diet. However, the complexities of diet have made identifying specific food intolerances difficult. Eating disorders can masquerade as IBS and may need specialist treatment. While typical food allergy is readily distinguished from IBS, the mechanisms of gut-specific adverse reactions to food are only just being defined. These may include gut-specific mast cell activation as well as non-specific activation by stressors and certain foods. Visceral hypersensitivity, in some cases mediated by mast cell activation, plays a key part in making otherwise innocuous gut stimuli painful. Rapidly fermented poorly absorbed carbohydrates produce gaseous distension as well as short-chain fatty acids and lowering of colonic pH which may cause symptoms in IBS patients. Limiting intake of these in low FODMAP and related diets has proven popular and apparently successful in many patients. Existing diet, colonic microbiota and their metabolic products may be helpful in predicting who will respond. Wheat intolerance may reflect the fact that wheat is often a major source of dietary FODMAPs. It may also be either a forme fruste of coeliac disease or non-specific immune activation. Wheat exclusion can be successful in some of these patients. More research is needed to fully understand the mechanisms of food intolerances and how to best ameliorate them in a personalised medicine approach to diet in IBS.

Clinical Practice Guidelines for Irritable Bowel Syndrome in Korea, 2017 Revised Edition

In 2011, the Korean Society of Neurogastroenterology and Motility (KSNM) published clinical practice guidelines on the management of irritable bowel syndrome (IBS) based on a systematic review of the literature. The KSNM planned to update the clinical practice guidelines to support primary physicians, reduce the socioeconomic burden of IBS, and reflect advances in the pathophysiology and management of IBS. The present revised version of the guidelines is in continuity with the previous version and targets adults diagnosed with, or suspected to have, IBS. A librarian created a literature search query, and a systematic review was conducted to identify candidate guidelines. Feasible documents were verified based on predetermined inclusion and exclusion criteria. The candidate seed guidelines were fully evaluated by the Guidelines Development Committee using the Appraisal of Guidelines for Research and Evaluation II quality assessment tool. After selecting 7 seed guidelines, the committee prepared evidence summaries to generate data exaction tables. These summaries comprised the 4 main themes of this version of the guidelines: colonoscopy; a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; probiotics; and rifaximin. To adopt the core recommendations of the guidelines, the Delphi technique (ie, a panel of experts on IBS) was used. To enhance dissemination of the clinical practice guidelines, a Korean version will be made available, and a food calendar for patients with IBS is produced.

The Role of Diet in the Treatment of Irritable Bowel Syndrome: A Systematic Review

Irritable bowel syndrome (IBS) is a multifaceted illness involving maladaptive shifts in the gut microbiota that affect the enteric nervous and immune systems, mucosal barrier function, the balance of neurotransmitters and hormones, and emotional well-being. There is abundant evidence indicating that certain foods elicit symptoms in IBS. Numerous elimination-type diets have been shown to alleviate symptoms. However, among these, the most controversial is a group of foods called fructo, oligo-, di-, and monosaccharides and polyols (FODMAPs). This paper reviews the role of diet and systematically analyze the literature for the role of FODMAPs in IBS.

A Novel Prebiotic Blend Product Prevents Irritable Bowel Syndrome in Mice by Improving Gut Microbiota and Modulating Immune Response

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder yet it still lacks effective prevention therapies. The aim of this study is to determine whether a novel prebiotic blend (PB) composed of fructo-oligosaccharide (FOS), galactooligosaccharide (GOS), inulin and anthocyanins could be effective in preventing the development of IBS. We explored the possible mechanisms both in animal and in cells. Post-infectious IBS models in C57BL/6 mice were established and were pretreated with the PB, PB and probiotic strains 8 weeks in advance of infection. Eight weeks after infection, intestinal tissues were collected for assessing histomorphology, visceral sensitivity, barrier function, pro-inflammatory cytokines expression and proteomics analysis. Fecal samples were also collected for microbiota analysis. The pro-inflammatory cytokines expression in Caco-2 cells were evaluated after co-incubation with PB and Salmonella typhimurium 14028. The results showed that PB significantly decreased the pro-inflammatory cytokines both in infected Caco-2 cells and PI-IBS models. The loss of body weight, decreased expression of tight junction protein Occludin (OCLN), and changes of the microbiota composition induced by infections could be greatly improved by PB intervention (p < 0.05). The proteomics analysis revealed that this function was associated with Peroxisome proliferator-activated receptor (PPAR)γ pathway.

Colon Hypersensitivity to Distension, Rather Than Excessive Gas Production, Produces Carbohydrate-Related Symptoms in Individuals With Irritable Bowel Syndrome

BACKGROUND & AIMS

Poorly digested, fermentable carbohydrates may induce symptoms of irritable bowel syndrome (IBS) via unclear mechanisms. We performed a randomized trial with magnetic resonance imaging (MRI) analysis to investigate correlations between symptoms and changes in small- and large-bowel contents after oral challenge.

METHODS

We performed a 3-period, cross-over study of 29 adult patients with IBS (based on Rome III criteria, with symptoms of abdominal pain or discomfort for at least 2 days/wk) and reported bloating. In parallel, we performed the same study of 29 healthy individuals (controls). Studies were performed in the United Kingdom from January 2013 through February 2015. On 3 separate occasions (at least 7 days apart), subjects were given a 500-mL drink containing 40 g of carbohydrate (glucose in the first period, fructose in the second, and inulin in the third, in a random order). Levels of breath hydrogen were measured and intestinal content was assessed by MRI before and at various time points after consumption of each drink. Symptoms were determined based on subjects' responses to the Hospital Anxiety and Depression Scale questionnaire and the Patient Health Questionnaire-15. The primary end point was whether participants had a clinically important symptom response during the 300 minutes after consumption of the drink.

RESULTS

More patients with IBS reached the predefined symptom threshold after intake of inulin (13 of 29) or fructose (11 of 29) than glucose (6 of 29). Symptoms peaked sooner after intake of fructose than inulin. Fructose increased small-bowel water content in both patients and controls whereas inulin increased colonic volume and gas in both. Fructose and inulin increased breath hydrogen levels in both groups, compared with glucose; fructose produced an earlier increase than inulin. Controls had lower symptom scores during the period after drink consumption than patients with IBS, despite similar MRI parameters and breath hydrogen responses. In patients who reached the symptom threshold after inulin intake, peak symptom intensity correlated with peak colonic gas (r = 0.57; P < .05). Changes in MRI features and peak breath hydrogen levels were similar in patients who did and did not reach the symptom threshold.

CONCLUSIONS

Patients with IBS and healthy individuals without IBS (controls) have similar physiological responses after intake of fructose or inulin; patients reported symptoms more frequently after inulin than controls. In patients with a response to inulin, symptoms related to levels of intraluminal gas, but peak gas levels did not differ significantly between responders, nonresponders, or controls. This indicates that colonic hypersensitivity to distension, rather than excessive gas production, produces carbohydrate-related symptoms in patients with IBS. Clinicaltrials.gov no: NCT01776853.

British Dietetic Association systematic review and evidence-based practice guidelines for the dietary management of irritable bowel syndrome in adults (2016 update)

BACKGROUND

The first British Dietetic Association (BDA) guidelines for the dietary management of irritable bowel syndrome (IBS) in adults were published in 2012. Subsequently, there has been a wealth of new research. The aim of this work was to systematically review the evidence for the role of diet in the management of IBS and to update the guidelines.

METHODS

Twelve questions relating to diet and IBS were defined based on review of the previous guideline questions, current evidence and clinical practice. Chosen topics were on healthy eating and lifestyle (alcohol, caffeine, spicy food, elimination diets, fat and fluid intakes and dietary habits), milk and dairy, dietary fibre, fermentable carbohydrates, gluten, probiotics and elimination diets/food hypersensitivity. Data sources were CINAHL, Cochrane Register of Controlled Trials, Embase, Medline, Scopus and Web of Science up to October 2015. Studies were assessed independently in duplicate using risk of bias tools specific to each included study based on inclusion and exclusion criteria for each question. National Health and Medical Research Council grading evidence levels were used to develop evidence statements and recommendations, in accordance with Practice-based Evidence in Nutrition Global protocol used by the BDA.

RESULTS

Eighty-six studies were critically appraised to generate 46 evidence statements, 15 clinical recommendations and four research recommendations. The IBS dietary algorithm was simplified to first-line (healthy eating, provided by any healthcare professional) and second-line [low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) to be provided by dietitian] dietary advice.

CONCLUSIONS

These guidelines provide updated comprehensive evidence-based details to achieve the successful dietary management of IBS in adults.

Gut microbiota role in irritable bowel syndrome: New therapeutic strategies

In the last decade the impressive expansion of our knowledge of the vast microbial community that resides in the human intestine, the gut microbiota, has provided support to the concept that a disturbed intestinal ecology might promote development and maintenance of symptoms in irritable bowel syndrome (IBS). As a correlate, manipulation of gut microbiota represents a new strategy for the treatment of this multifactorial disease. A number of attempts have been made to modulate the gut bacterial composition, following the idea that expansion of bacterial species considered as beneficial (Lactobacilli and Bifidobacteria) associated with the reduction of those considered harmful (Clostridium, Escherichia coli, Salmonella, Shigella and Pseudomonas) should attenuate IBS symptoms. In this conceptual framework, probiotics appear an attractive option in terms of both efficacy and safety, while prebiotics, synbiotics and antibiotics still need confirmation. Fecal transplant is an old treatment translated from the cure of intestinal infective pathologies that has recently gained a new life as therapeutic option for those patients with a disturbed gut ecosystem, but data on IBS are scanty and randomized, placebo-controlled studies are required.

The role of fiber supplementation in the treatment of irritable bowel syndrome: a systematic review and meta-analysis

Irritable bowel syndrome (IBS) is a functional bowel disorder associated with a wide variety of clinical symptoms. The use of fiber in treatment of IBS is well established, but recent reviews have shown conflicting evidence. The aim of our review was to study the effects of fiber (soluble and insoluble) on the symptoms of IBS. Medline, EMBASE, Cochrane Central, CINAHL, LILACS, and ClinicalTrials.gov were searched for appropriate studies. Two reviewers screened the title/abstract and full text against the inclusion criterion - that is, randomized control trials/crossover studies that compare fiber with placebo for its effect on IBS in an outpatient setting. Independent double data extraction was performed across multiple fields. An assessment of the risk of bias and tests for heterogeneity were carried out, along with a meta-analysis of the outcomes of interest. The search yielded 4199 unique records: 121 were selected after title/abstract screening and 22 after full screening. There was moderate clinical, methodological, and statistical heterogeneity across studies, with a moderate risk of bias. Overall, there was a significant improvement in global assessment of symptoms among those randomized to fiber [risk ratio: 1.27; 95% confidence interval (CI): 1.05-1.54]. Soluble fiber improved assessment of symptoms (risk ratio 1.49; 95% CI: 1.09-2.03), as well as the abdominal pain score (mean difference: -1.84; 95% CI: -2.72 to -0.97), with insoluble fiber not showing improvement in any outcome. Soluble fiber appears to improve symptoms of IBS, whereas there is no evidence for recommending insoluble fiber for IBS.

Irritable bowel syndrome: The evolution of multi-dimensional looking and multidisciplinary treatments

Irritable bowel syndrome (IBS) is common in the society. Among the putative pathogeneses, gut dysmotility results in pain and disturbed defecation. The latter is probably caused by the effect of abnormal gut water secretion. The interaction between abnormal gas accumulation, abdominal pain and bloating remains controversial. Visceral hypersensitivity and its modification along with the central transmission are the characteristics of IBS patients. The identification of biologic markers based on genetic polymorphisms is undetermined. Imbalanced gut microbiota may alter epithelial permeability to activate nociceptive sensory pathways which in turn lead to IBS. Certain food constituents may exacerbate bowel symptoms. The impact of adult and childhood abuses on IBS is underestimated. Using the concept of biopsychosocial dysfunction can integrate multidimensional pathogeneses. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are the first-line drug treatment. New drugs targeting receptors governing bowel motility, sensation and secretion can be considered, but clinicians must be aware of their potential serious side effects. Psychiatric drugs and modalities may be the final options for treating intractable subjects. Probiotics of multi-species preparations are safe and worth to be considered for the treatment. Antibiotics are promising but their long-term safety and effectiveness are unknown. Diet therapy including exclusion of certain food constituents is an economic measure. Using relatively safe complementary and alternative medicines (CAMs) may be optional to those patients who failed classical treatment. In conclusion, IBS is a heterogeneous disorder with multidimensional pathogeneses. Personalized medicines with multidisciplinary approaches using different classes of drugs, psychiatric measures, probiotics and antibiotics, dietary therapy, and finally CAMs, can be considered.

Challenges in management of irritable bowel syndrome in children

Irritable bowel syndrome (IBS) is a common cause of recurrent abdominal pain (RAP) in children and can be a debilitating experience for both child and family. Organic causes of RAP symptoms such as celiac and inflammatory bowel diseases should be excluded before a diagnosis of IBS is made. Treatment consists of dietary manipulation, drugs, and stress management. Newer therapies may offer better control of symptoms with minimal side-effects. This article discusses the challenges faced by pediatricians in managing IBS and reviews management in the context of children from the Indian subcontinent.

Delayed gastric emptying and reduced postprandial small bowel water content of equicaloric whole meal bread versus rice meals in healthy subjects: novel MRI insights

BACKGROUND/OBJECTIVES

Postprandial bloating is a common symptom in patients with functional gastrointestinal (GI) diseases. Whole meal bread (WMB) often aggravates such symptoms though the mechanisms are unclear. We used magnetic resonance imaging (MRI) to monitor the intragastric fate of a WMB meal (11% bran) compared with a rice pudding (RP) meal.

SUBJECTS/METHODS

Twelve healthy volunteers completed this randomised crossover study. They fasted overnight and after an initial MRI scan consumed a glass of orange juice with a 2267 kJ WMB or an equicaloric RP meal. Subjects underwent serial MRI scans every 45 min up to 270 min to assess gastric volumes and small bowel water content, and completed a GI symptom questionnaire.

RESULTS

The MRI intragastric appearance of the two meals was markedly different. The WMB meal formed a homogeneous dark bolus with brighter liquid signal surrounding it. The RP meal separated into an upper liquid layer and a lower particulate layer allowing more rapid emptying of the liquid compared with solid phase (sieving). The WMB meal had longer gastric half-emptying times (132±8 min) compared with the RP meal (104±7 min), P<0.008. The WMB meal was associated with markedly reduced MRI-visible small bowel free mobile water content compared with the RP meal, P<0.0001.

CONCLUSIONS

WMB bread forms a homogeneous bolus in the stomach, which inhibits gastric sieving and hence empties slower than the equicaloric rice meal. These properties may explain why wheat causes postprandial bloating and could be exploited to design foods that prolong satiation.

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.

British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults

BACKGROUND

 Irritable bowel syndrome (IBS) is a chronic debilitating functional gastrointestinal disorder. Diet and lifestyle changes are important management strategies. The aim of these guidelines is to systematically review key aspects of the dietary management of IBS, with the aim of providing evidence-based guidelines for use by registered dietitians.

METHODS

Questions relating to diet and IBS symptom management were developed by a guideline development group. These included the role of milk and lactose, nonstarch polysaccharides (NSP), fermentable carbohydrates in abdominal bloating, probiotics and empirical or elimination diets. A comprehensive literature search was conducted and relevant studies from January 1985 to November 2009 were identified using the electronic database search engines: Cinahl, Cochrane Library, Embase, Medline, Scopus and Web of Science. Evidence statements, recommendations, good practice points and research recommendations were developed.

RESULTS

Thirty studies were critically appraised. A dietetic care pathway was produced following a logical sequence of treatment and formed the basis of these guidelines. Three lines of dietary management were identified. first line: Clinical and dietary assessment, healthy eating and lifestyle management with some general advice on lactose and NSP. Second line: Advanced dietary interventions to improve symptoms based on NSP, fermentable carbohydrates and probiotics. Third line: Elimination and empirical diets. Research recommendations were also identified relating to the need for adequately powered and well designed randomised controlled trials.

CONCLUSIONS

These guidelines provide evidence-based details of how to achieve the successful dietary management of IBS.

Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. The role of pharmacotherapy for IBS is limited and focused mainly on symptom control.

OBJECTIVES

The objective of this systematic review was to evaluate the efficacy of bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome.

SEARCH STRATEGY

Computer assisted structured searches of MEDLINE, EMBASE, The Cochrane library, CINAHL and PsychInfo were conducted for the years 1966-2009. An updated search in April 2011 identified 10 studies which will be considered for inclusion in a future update of this review.

SELECTION CRITERIA

Randomized controlled trials comparing bulking agents, antispasmodics or antidepressants with a placebo treatment in patients with irritable bowel syndrome aged over 12 years were considered for inclusion. Only studies published as full papers were included. Studies were not excluded on the basis of language. The primary outcome had to include improvement of abdominal pain, global assessment or symptom score.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the selected studies. Risk Ratios (RR) and Standardized Mean Differences (SMD) with 95% confidence intervals (CI) were calculated. A proof of practice analysis was conducted including sub-group analyses for different types of  bulking agents, spasmolytic agents or antidepressant medication. This was followed by a proof of principle analysis where only the studies with adequate allocation concealment were included.

MAIN RESULTS

A total of 56 studies (3725 patients) were included in this review. These included 12 studies of bulking agents (621 patients), 29 of antispasmodics (2333 patients), and 15 of antidepressants (922 patients). The risk of bias was low for most items. However, selection bias is unclear for many of the included studies because the methods used for randomization and allocation concealment were not described. No beneficial effect for bulking agents over placebo was found for improvement of abdominal pain (4 studies; 186 patients; SMD 0.03; 95% CI -0.34 to 0.40; P = 0.87), global assessment (11 studies; 565 patients; RR 1.10; 95% CI 0.91 to 1.33; P = 0.32) or symptom score (3 studies; 126 patients SMD -0.00; 95% CI -0.43 to 0.43; P = 1.00). Subgroup analyses for insoluble and soluble fibres also showed no statistically significant benefit. Separate analysis of the studies with adequate concealment of allocation did not change these results. There was a beneficial effect for antispasmodics over placebo for improvement of abdominal pain (58% of antispasmodic patients improved compared to 46% of placebo; 13 studies; 1392 patients; RR 1.32; 95% CI 1.12 to 1.55; P < 0.001; NNT = 7), global assessment (57% of antispasmodic patients improved compared to 39% of placebo; 22 studies; 1983 patients; RR 1.49; 95% CI 1.25 to 1.77; P < 0.0001; NNT = 5) and symptom score (37% of antispasmodic patients improved compared to 22% of placebo; 4 studies; 586 patients; RR 1.86; 95% CI 1.26 to 2.76; P < 0.01; NNT = 3). Subgroup analyses for different types of antispasmodics found statistically significant benefits for cimteropium/ dicyclomine, peppermint oil, pinaverium and trimebutine. Separate analysis of the studies with adequate allocation concealment found a significant benefit for improvement of abdominal pain. There was a beneficial effect for antidepressants over placebo for improvement of abdominal pain (54% of antidepressants patients improved compared to 37% of placebo; 8 studies; 517 patients; RR 1.49; 95% CI 1.05 to 2.12; P = 0.03; NNT = 5), global assessment (59% of antidepressants patients improved compared to 39% of placebo; 11 studies; 750 patients; RR 1.57; 95% CI 1.23 to 2.00; P < 0.001; NNT = 4) and symptom score (53% of antidepressants patients improved compared to 26% of placebo; 3 studies; 159 patients; RR 1.99; 95% CI 1.32 to 2.99; P = 0.001; NNT = 4). Subgroup analyses showed a statistically significant benefit for selective serotonin releasing inhibitors (SSRIs) for improvement of  global assessment and for tricyclic antidepressants (TCAs) for improvement of abdominal pain and symptom score. Separate analysis of studies with adequate allocation concealment found a significant benefit for improvement of symptom score and global assessment. Adverse events were not assessed as an outcome in this review.

AUTHORS' CONCLUSIONS

There is no evidence that bulking agents are effective for treating IBS.  There is evidence that antispasmodics are effective for the treatment of IBS. The individual subgroups which are effective include: cimetropium/dicyclomine, peppermint oil, pinaverium and trimebutine. There is good evidence that antidepressants are effective for the treatment of IBS. The subgroup analyses for SSRIs and TCAs are unequivocal and their effectiveness may depend on the individual patient. Future research should use rigorous methodology and valid outcome measures.

[Guidelines for the treatment of irritable bowel syndrome]

Traditional symptom-based therapies of irritable bowel syndrome (IBS) are directed at the relief of individual IBS symptoms, but they are often of limited efficacy in addressing the entire symptom complex. Combinations of drugs to target bothersome symptoms are suggested as the first-line pharmacologic treatment. Increasing knowledge of the pathophysiology and molecular mechanisms of IBS has resulted in the development of several new therapeutic approaches. Thirteen consensus statements for the treatment of IBS were developed using the modified Delphi approach. Exclusion diets have modest efficacy in improving symptoms in some IBS patients. Symptom-based therapies with dietary fiber, bulking agents, laxatives, antispasmodics and laxatives are effective in the improvement of some individual symptoms, e.g. dietary fiber and bulking agents for constipation, laxatives for constipation, antispasmodics for abdominal pain and discomfort, antidiarrheals for diarrhea. 5HT3 receptor antagonists and 5HT((4)) receptor agonists are effective in the relief of global IBS symptoms and individual symptoms such as abdominal pain and abnormal bowel habits. A short term course of nonabsorbable antibiotics may improve global IBS symptoms, particularly in patients with diarrhea- predominant IBS. Some probiotics appear to have the potential benefit in improving global IBS symptoms. Selective C-2 chloride channel activator is more effective than placebo at relieving global IBS symptoms in patients with constipation-predominant IBS. Both tricyclic antidepressants and selective serotonin reuptake inhibitors are equally effective in relieving global IBS symptoms, and have some benefits in treating abdominal pain. Certain types of psychologic therapy may be effective in improving global symptoms in some IBS patients. Further studies are strongly needed to develop better treatment strategies for Korean patients with IBS.

Asian consensus on irritable bowel syndrome

BACKGROUND AND AIMS

Many of the ideas on irritable bowel syndrome (IBS) are derived from studies conducted in Western societies. Their relevance to Asian societies has not been critically examined. Our objectives were to bring to attention important data from Asian studies, articulate the experience and views of our Asian experts, and provide a relevant guide on this poorly understood condition for doctors and scientists working in Asia.

METHODS

A multinational group of physicians from Asia with special interest in IBS raised statements on IBS pertaining to symptoms, diagnosis, epidemiology, infection, pathophysiology, motility, management, and diet. A modified Delphi approach was employed to present and grade the quality of evidence, and determine the level of agreement.

RESULTS

We observed that bloating and symptoms associated with meals were prominent complaints among our IBS patients. In the majority of our countries, we did not observe a female predominance. In some Asian populations, the intestinal transit times in healthy and IBS patients appear to be faster than those reported in the West. High consultation rates were observed, particularly in the more affluent countries. There was only weak evidence to support the perception that psychological distress determines health-care seeking. Dietary factors, in particular, chili consumption and the high prevalence of lactose malabsorption, were perceived to be aggravating factors, but the evidence was weak.

CONCLUSIONS

This detailed compilation of studies from different parts of Asia, draws attention to Asian patients' experiences of IBS.

Postprandial changes in small bowel water content in healthy subjects and patients with irritable bowel syndrome

BACKGROUND & AIMS

Postprandial symptoms are common in patients with irritable bowel syndrome with diarrhea (IBS-D) and could be diet related. We studied postprandial changes in distribution of water in the upper gastrointestinal tract of healthy volunteers (HVs) and patients with IBS-D after contrasting meals.

METHODS

In study 1, 11 HVs consumed 350-mL test meals with 5% mannitol (unabsorbable) or 5% glucose (readily absorbed). In study 2, 17 HVs consumed a 331-kcal meal, with or without 15 g bran. In study 3, 26 patients with IBS-D consumed the study 2 diet with bran meal. All subjects underwent serial magnetic resonance imaging analysis.

RESULTS

In study 1, subjects' small bowel water content (SBWC) increased after the mannitol but not glucose meals, reaching 381 mL (interquartile range, 343-491 mL) and 47 mL (18-78 mL), respectively, 40 minutes after eating (P < .001). In study 2, SBWC initially decreased after both meal types and then increased, plateauing at 180-405 minutes and was greater after the bran meal (P = .02). In study 3, fasting and postprandial SBWC was lower in IBS-D than in HVs (P < .05 and P < .0001, respectively). Patients with IBS-D had faster orocecal transit times (135 minutes; 90-180 minutes) compared with HVs (225 minutes; 203-293 minutes; P < .0001) and reduced terminal ileum diameter (P < .003).

CONCLUSIONS

Postprandial SBWC initially decreases, because of rapid, nutrient-driven fluid absorption, and then increases after a mixed liquid/solid meal. Patients with IBS-D have reduced fasting and postprandial SBWC with faster transit, possibly indicating increased small intestinal tone.

Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial

OBJECTIVE

To determine the effectiveness of increasing the dietary content of soluble fibre (psyllium) or insoluble fibre (bran) in patients with irritable bowel syndrome.

DESIGN

Randomised controlled trial.

SETTING

General practice.

PARTICIPANTS

275 patients aged 18-65 years with irritable bowel syndrome.

INTERVENTIONS

12 weeks of treatment with 10 g psyllium (n=85), 10 g bran (n=97), or 10 g placebo (rice flour) (n=93).

MAIN OUTCOME MEASURES

The primary end point was adequate symptom relief during at least two weeks in the previous month, analysed after one, two, and three months of treatment to assess both short term and sustained effectiveness. Secondary end points included irritable bowel syndrome symptom severity score, severity of abdominal pain, and irritable bowel syndrome quality of life scale.

RESULTS

The proportion of responders was significantly greater in the psyllium group than in the placebo group during the first month (57% v 35%; relative risk 1.60, 95% confidence interval 1.13 to 2.26) and the second month of treatment (59% v 41%; 1.44, 1.02 to 2.06). Bran was more effective than placebo during the third month of treatment only (57% v 32%; 1.70, 1.12 to 2.57), but this was not statistically significant in the worst case analysis (1.45, 0.97 to 2.16). After three months of treatment, symptom severity in the psyllium group was reduced by 90 points, compared with 49 points in the placebo group (P=0.03) and 58 points in the bran group (P=0.61 versus placebo). No differences were found with respect to quality of life. Fifty four (64%) of the patients allocated to psyllium, 54 (56%) in the bran group, and 56 (60%) in the placebo group completed the three month treatment period. Early dropout was most common in the bran group; the main reason was that the symptoms of irritable bowel syndrome worsened.

CONCLUSIONS

Psyllium offers benefits in patients with irritable bowel syndrome in primary care.

TRIAL REGISTRATION

Clinical trials NCT00189033.

Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial

OBJECTIVE

To determine the effectiveness of increasing the dietary content of soluble fibre (psyllium) or insoluble fibre (bran) in patients with irritable bowel syndrome.

DESIGN

Randomised controlled trial.

SETTING

General practice.

PARTICIPANTS

275 patients aged 18-65 years with irritable bowel syndrome.

INTERVENTIONS

12 weeks of treatment with 10 g psyllium (n=85), 10 g bran (n=97), or 10 g placebo (rice flour) (n=93).

MAIN OUTCOME MEASURES

The primary end point was adequate symptom relief during at least two weeks in the previous month, analysed after one, two, and three months of treatment to assess both short term and sustained effectiveness. Secondary end points included irritable bowel syndrome symptom severity score, severity of abdominal pain, and irritable bowel syndrome quality of life scale.

RESULTS

The proportion of responders was significantly greater in the psyllium group than in the placebo group during the first month (57% v 35%; relative risk 1.60, 95% confidence interval 1.13 to 2.26) and the second month of treatment (59% v 41%; 1.44, 1.02 to 2.06). Bran was more effective than placebo during the third month of treatment only (57% v 32%; 1.70, 1.12 to 2.57), but this was not statistically significant in the worst case analysis (1.45, 0.97 to 2.16). After three months of treatment, symptom severity in the psyllium group was reduced by 90 points, compared with 49 points in the placebo group (P=0.03) and 58 points in the bran group (P=0.61 versus placebo). No differences were found with respect to quality of life. Fifty four (64%) of the patients allocated to psyllium, 54 (56%) in the bran group, and 56 (60%) in the placebo group completed the three month treatment period. Early dropout was most common in the bran group; the main reason was that the symptoms of irritable bowel syndrome worsened.

CONCLUSIONS

Psyllium offers benefits in patients with irritable bowel syndrome in primary care.

TRIAL REGISTRATION

Clinical trials NCT00189033.

Review article: probiotics and prebiotics in irritable bowel syndrome

BACKGROUND

The human gut harbours a complex community of bacteria whose relationship with their host is normally mutually beneficial. Recent studies suggest a disturbance of this relationship in irritable bowel syndrome (IBS) and the potential to correct this using prebiotics and probiotics.

AIM

To review the mechanisms of action of probiotics and prebiotics in IBS and to assess their performance in clinical trials.

METHODS

Articles relating to modes of action and randomized control trials of treatment were reviewed by searching PubMed using terms 'probiotic', 'prebiotic' and 'irritable bowel'. Small uncontrolled studies in IBS were excluded.

RESULTS

Probiotics can enhance gut barrier function, inhibit pathogen binding and modulate gut inflammatory response. They can also reduce visceral hypersensitivity associated with both inflammation and psychological stress. Probiotics can alter colonic fermentation and stabilize the colonic microbiota. Several large randomized, placebo-controlled trials of adequate design have shown an improvement in flatulence and abdominal distension with a reduction in composite IBS symptoms scores.

CONCLUSIONS

Each probiotic has unique features and IBS patients are heterogeneous. Future efforts should be directed to identifying biomarkers of responsiveness to facilitate better targeting of treatment and hence improved efficacy.

Effects of anti-secretory factor (ASF) on irritable bowel syndrome (IBS). A double-blind, randomized study

OBJECTIVE

To evaluate the role of the endogenous protein anti-secretory factor (ASF) on the symptoms, especially loose stools, in irritable bowel ayndrome (IBS).

DESIGN

A diet with specially processed cereals (SPC) known to induce ASF production was used in patients with IBS, in an eight-week randomized, placebo-controlled study.

SUBJECTS

Eighty-two patients with IBS were randomized to a diet with either SPC or placebo.

MAIN OUTCOME MEASURES

The overall clinical condition and the quality of life were measured by VAS and SF-36 questionnaire, respectively. The plasma levels of ASF were determined in 14 patients with dominating loose stools before and after diet.

RESULTS

All patients significantly (p<0.001) improved in IBS-related symptoms irrespective of active or placebo diet. In an active-diet sub-group with diarrhoea (n=11) there was a significant (p<0.05) correlation between the increase of plasma ASF level and the improvement on the VAS.

CONCLUSION

Both study groups improved significantly on the VAS but no additive effect was seen for the active treatment. In the sub-group with loose stools, the SPC diet induced ASF plasma levels in IBS patients and was correlated to significant symptom improvement in the individual patient.

Irritable Bowel Syndrome: A Practical Review

The epidemiology and current understanding of the pathophysiology of irritable bowel syndrome is reviewed, beginning with a historical perspective. The roles of genetics, environment, allergy, infection and inflammation, bacterial overgrowth, hormones and motility abnormalities are discussed. Using the current evidence-based literature, the practical approach of diagnosis and treatment is outlined, including traditional modalities and newer therapeutic agents such as serotonin modulators.

Systematic review: the efficacy of treatments for irritable bowel syndrome--a European perspective

BACKGROUND

Irritable bowel syndrome (IBS) is a common, chronic disorder, characterized by abdominal pain/discomfort, bloating and altered bowel habit.

AIM

To conduct a systematic evidence-based review of pharmacological therapies currently used, or in clinical development, for the treatment of IBS in Europe. The safety and tolerability of these therapies are the subject of an accompanying review.

METHODS

A literature search was completed for randomized controlled studies which included adult patients with IBS and an active or placebo control, assessed IBS symptoms, and were published in English between January 1980 and June 2005. The level of evidence for efficacy was graded according to the quality of the trial design and the study outcome.

RESULTS

There is some evidence for improvement of individual IBS symptoms with antidiarrhoeals (diarrhoea), antispasmodics (abdominal pain/discomfort), bulking agents (constipation), tricyclic antidepressants (abdominal pain/discomfort) and behavioural therapy. In contrast, there is strong evidence for the improvement of global IBS symptoms with two new serotonergic agents: the 5-HT4 selective agonist tegaserod (IBS with constipation) and the 5-HT3 antagonist alosetron (IBS with diarrhoea). Further data are required for the 5-HT3 antagonist, cilansetron, and the mixed 5-HT3 antagonist/5-HT4 agonist renzapride before their utility in IBS can be appraised.

CONCLUSIONS

There is limited evidence for the efficacy, safety and tolerability of therapies currently available in Europe for the treatment of IBS. Overall, there is an absence of pharmacological agents licensed specifically for the treatment of IBS subtypes, and new agents are awaited in Europe that will allow changes in clinical practice to focus on and improve global IBS symptoms.

Functional bowel disorders

Employing a consensus approach, our working team critically considered the available evidence and multinational expert criticism, revised the Rome II diagnostic criteria for the functional bowel disorders, and updated diagnosis and treatment recommendations. Diagnosis of a functional bowel disorder (FBD) requires characteristic symptoms during the last 3 months and onset > or =6 months ago. Alarm symptoms suggest the possibility of structural disease, but do not necessarily negate a diagnosis of an FBD. Irritable bowel syndrome (IBS), functional bloating, functional constipation, and functional diarrhea are best identified by symptom-based approaches. Subtyping of IBS is controversial, and we suggest it be based on stool form, which can be aided by use of the Bristol Stool Form Scale. Diagnostic testing should be guided by the patient's age, primary symptom characteristics, and other clinical and laboratory features. Treatment of FBDs is based on an individualized evaluation, explanation, and reassurance. Alterations in diet, drug treatment aimed at predominant symptoms, and psychotherapy may be beneficial.

The role of fiber in the treatment of irritable bowel syndrome: therapeutic recommendations

Irritable bowel syndrome is a common clinical condition that often presents a therapeutic challenge. There is no standard therapy and a multilevel approach is recommended. A high-fiber diet is often one of these components. Many investigators have studied the effectiveness of either fiber supplementation or bulking agents in patients with irritable bowel syndrome. The purpose of this review is to summarize the current literature on the use of fiber in irritable bowel syndrome and to provide some specific recommendations. Systematic reviews of these trials have generally not found fiber to be significantly more effective than placebo at relieving global irritable bowel syndrome symptoms. There may be differences between results obtained with soluble and insoluble fiber. Adverse effects of fiber use may include abdominal discomfort and bloating. Although dietary fiber or bulking agents do not appear to be useful as sole treatment of irritable bowel syndrome, they may have a limited role in empiric therapy depending upon the patient's symptom complex, especially if constipation is the most significant symptom. The basic principles for using fiber therapy are to start with a low dose and increase slowly, to give an adequate trial and to evaluate the results early and periodically.

Nutrition and motility disorders

The purpose of this article is to give an overview of the relation between feeding and gastrointestinal symptoms and complaints, and to review different motility disorders that have implications for food intake. We also report the consequences for nutrition state and the evidence-based principles of dietary modification in patients with motility disorders.

The placebo effect in irritable bowel syndrome trials: a meta-analysis

BACKGROUND

Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response.

OBJECTIVES

To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response.

METHODS

We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied.

FINDINGS

Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026).

CONCLUSIONS

Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

Efficacy of current drug therapies in irritable bowel syndrome: what works and does not work

Based on current evidence, bulking agents are not more effective than placebo at improving global irritable bowel syndrome (IBS)symptoms, although they may increase stool frequency in large doses. Tricyclic antidepressants are more effective than placebo for patients with diarrhea-predominant IBS. Imodium is more effective than placebo at improving stool consistency and decreasing stool frequency in patients with IBS, and it may be an important component for treating diarrhea-predominant IBS. Antispasmodics agents available in the United States are not more effective than placebo for treating IBS, although the studies are small and poorly designed. There are no randomized controlled trials examining the efficacy of laxatives for managing IBS. Tegaserod is more effective than placebo at improving global IBS symptoms in women with nondiarrhea-predominant IBS. Alosetron is more effective than placebo in women with diarrhea-predominant IBS, although its use should be limited to patients who have failed conventional therapy because of its adverse event profile.

Use of diet and probiotic therapy in the irritable bowel syndrome: analysis of the literature

GOAL

The goal of this report is to review the use of dietary intake and probiotics in patients with irritable bowel syndrome (IBS) in published reports.

BACKGROUND

Dietary factors can be important in inducing symptoms that occur in patients with the IBS. Dietary intolerances, dietary allergies, specific food metabolites, and regular diet contents all may act as triggers and aggravate the symptoms of IBS; but when any of these mechanisms can be proven to cause the symptoms, then their elimination results in the resolution of that patient's IBS.

METHODS

Our previous review was updated. In addition, a careful Medline search was made for the years from 1975 to 2004 to evaluate human research reports on diet and probiotics in the IBS. Forty-six manuscripts were reviewed on diet and six were available on probiotic use in IBS. The most common dietary factor evaluated in the literature was bran, and the most common probiotic used was Lactobacillus plantarum.

CONCLUSIONS

Although investigations have shown that bran may be helpful in some patients, a complete review of the literature does not reveal conclusive evidence that diet therapy is effective in IBS. From the limited reports on probiotics, there appears to be a trend to decreasing symptoms. It is clear that much more prospective research is needed to study both dietary factors and probiotics in these areas.

Bulking agents, antispasmodic and antidepressant medication for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common health problem, often presenting in primary care as well as in internal medicine and gastroenterology outpatient clinics. Therapeutic options are dominated by drug therapies but there is uncertainty about their effectiveness.

OBJECTIVES

The primary objective of this review was to evaluate the efficacy of bulking agents, antispasmodic and antidepressant medication for the treatment of IBS.

SEARCH STRATEGY

A computer assisted search of MEDLINE, EMBASE, PsychInfo and the Cochrane Library was performed for the years 1966-2001; local and national databases were searched in 10 European countries.

SELECTION CRITERIA

Randomised trials comparing bulking agents, antispasmodic or antidepressant medications with a placebo, in IBS patients over 12 years of age. Only studies published as a full paper were included. No language criterion was applied.

DATA COLLECTION AND ANALYSIS

The search identified 687 studies, 66 of which fulfilled all eligibility criteria. After removal of cross-over studies that did not report separately on the first phase, data from 40 studies remained for analysis. Relative risk (RR), risk difference (RD) and standardized mean difference (SMD) along with 95% confidence intervals were calculated for all subgroups. The number needed to treat (NNT) was also calculated where appropriate.

MAIN RESULTS

Forty-one study reports from 40 studies, comprising 78 comparisons, were analysed. These included 11 reports on bulking agents, 6 on antidepressants, and 24 on spasmolytics.BULKING AGENTS: Three studies comprising 159 patients reported a dichotomous outcome for relief of abdominal pain. The pooled RR using a random effects model was 1.22 (95% CI 0.86 - 1.73). Three studies comprising 128 patients reported a continuous outcome for relief of abdominal pain. Using the random effects model, the SMD was 0.68 (95% CI -0.86 - 2.33). Nine studies comprising 482 patients reported a dichotomous outcome for global assessment of improvement. The pooled RR was 1.09 (95% CI 0.78 - 1.50). Five studies comprising 253 patients reported a dichotomous outcome for improvement of symptom score. The pooled RR using a random effects model was 0.93 (95% CI 0.56 - 1.54). Two studies comprising 70 patients reported a continuous outcome for improvement of symptom score; the SMD using a fixed effects model was -0.44 (95% CI -1.20 - 0.31). SPASMOLYTIC AGENTS: Eleven studies comprising 1260 patients reported a dichotomous outcome for relief of abdominal pain. The pooled RR using a random effects model was 1.34 (95% CI 1.13 - 1.59; RD=0.17, 95% CI 0.06 -0.28; NNT=6, 95% CI 4 - 15). Seven studies comprising 467 patients reported a continuous outcome for relief of abdominal pain. Using a fixed effects model the pooled SMD was -0.65 (95% CI -0.94 to -0.35). Sixteen studies comprising 1236 patients reported a dichotomous outcome for global assessment of improvement. The pooled RR using a random effects model was 1.42 (95% CI 1.17 - 1.72; RD=0.20, 95% CI 0.09 -0.30; NNT=5, 95% CI 3 - 11). One study comprising 34 patients reported a dichotomous variable for improvement of symptom score. The RR was 1.33 (95% CI 0.96 - 1.85). Three studies reported a continuous outcome for improvement of symptom score; two studies comprising 66 patients could be pooled. Using a fixed effects model, the SMD was -0.37 (95% CI -0.85 - 0.12). ANTIDEPRESSANTS: Two studies comprising 81 patients reported a dichotomous outcome for relief of abdominal pain. Using the random effects model, the pooled RR was 0.83 (95% CI 0.33 - 2.12). Two studies comprising 101 patients reported a continuous outcome for relief of abdominal pain. The SMD using a random effects model was -0.53 (95% CI -2.29 - 1.23). Four studies comprising 241 patients reported a dichotomous variable for global assessment of improvement. The pooled RR was 1.16 (95% CI 0.78 - 1.73).

AUTHORS' CONCLUSIONS

The evidence for efficacy of drug therapies for IBS is weak. Although there is evidence of benefit for antispasmodic drugs for abdominal pain and global assessment of symptoms; it is unclear whether anti-spasmodic subgroups are individually effective. There is no clear evidence of benefit for antidepressants or bulking agents. The physician should be aware that global assessment is a construct containing various dimensions. For each individual, these will have a different weighting and treatment should be aimed at the most debilitating symptom. Stool problems are by definition part of the IBS symptom complex. Bulking agents may improve constipation and can be used empirically, but should be evaluated at an early stage for individual benefit. Future research should pay attention to study methodology and the use of valid outcome measures.

Meta-analysis: The treatment of irritable bowel syndrome

To evaluate therapies available for the treatment of irritable bowel syndrome, and provide consensus recommendations for their use, a total of 51 double-blind clinical trials using bulking agents, prokinetics, antispasmodics, alosetron, tegaserod and antidepressants were selected. The quality of studies was assessed using 5-point scale. Meta-analyses were performed on all studies, and on 'high-quality studies'. The efficacy of fibre in the global irritable bowel syndrome symptoms relief (OR: 1.9; 95% CI:1.5-2.4) was lost after exclusion of low-quality trials (OR: 1.4; 95% CI: 1.0-2.0, P = 0.06). When excluding the low-quality trials, an improvement of global irritable bowel syndrome symptoms with all antispasmodics (OR: 2.1; 95% CI:1.8-2.9) was maintained only for octylonium bromide, but on the basis of only two studies. Antidepressants were effective (OR: 2.6, 95% CI: 1.9-3.5), even after exclusion of low-quality studies (OR: 1.9, 95% CI: 1.3-2.7). Alosetron (OR: 2.2; 95% CI: 1.9-2.6) and tegaserod (OR: 1.4; 95% CI: 1.2-1.5) showed a significant effect in women. We recommend the use of tegaserod for women with irritable bowel syndrome with constipation and alosetron for women with severe irritable bowel syndrome with diarrhoea. Antidepressants can be beneficial for irritable bowel syndrome with diarrhoea patients with severe symptoms. Loperamide can be recommended in painless diarrhoea. Evidence is weak to recommend the use of bulking agents in the treatment of irritable bowel syndrome with constipation.

Dietary Treatment of the Irritable Bowel Syndrome

Most patients with functional gastrointestinal disorders report that food ingestion appears to exacerbate their symptoms and consequently conclude that they have some form of gastrointestinal food allergy or intolerance. Dietary management of functional gastrointestinal conditions is an attractive therapeutic option for the patient and physician alike because it is safe and economical and empowers the patient to help themselves. However, in practice, dietary manipulation frequently yields rather disappointing results. Exclusion diets can be helpful, but are labor intensive and occasionally can be very restrictive. Laboratory testing for immunoglobulin E food antibodies usually is not helpful, except in a small subgroup of patients with diarrhea, predominant irritable bowel syndrome (IBS), and atopy. There is some preliminary evidence to suggest that elimination diets based on immunoglobulin G food antibody testing may possibly have therapeutic potential in IBS, but this requires confirmation.

Diagnosis and therapy of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gut functional diseases, affecting 10-20% of people worldwide. Although most patients do not seek medical help, the disease accounts for huge costs for both patients and health-care systems and worsens significantly patients' quality of life. Diagnosis is based on the identification of symptoms according to Manning, Rome I and Rome II criteria and exclusion of alarm indicators. IBS symptoms overlap with those of coeliac disease, lactose intolerance, food allergies and bile salt malabsorption. The treatment of IBS is centred on an excellent doctor-patient relationship along with drugs targeting the predominant symptom, especially during exacerbations. Current pharmacological remedies are unsatisfactory due to the high number of patients complaining of lack of response and/or symptom recurrence. Although useful in some IBS patients, the validity of psychotherapy deserves further investigation. A wide array of potentially useful drugs are currently under consideration in pre-clinical trials. A better understanding of the pathogenetic mechanisms underlying IBS may help to develop more effective drugs for this disease.

Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome

BACKGROUND

Both high-fibre dietary advice and the prescription of fibre as a bulking agent are very common in primary and secondary care management of irritable bowel syndrome. Irritable bowel syndrome patients with constipation may have delayed intestinal transit. Therefore, fibres that accelerate intestinal transit may be beneficial in these patients. The uncertain benefits reported in several clinical studies, however, have led us to reappraise the value of fibre in irritable bowel syndrome management.

AIM

To quantify the effect of different types of fibre on global and symptom relief from irritable bowel syndrome.

METHODS

Using a structured literature search in MEDLINE (1966-2002), we selected randomized controlled trials involving irritable bowel syndrome patients treated with fibre. Analyses were performed for the total group and for trials using soluble and insoluble fibre separately.

RESULTS

Seventeen studies were included in the analysis. None investigated primary care irritable bowel syndrome patients. Fibre, in general, was effective in the relief of global irritable bowel syndrome symptoms [relative risk, 1.33; 95% confidence interval (CI), 1.19-1.50]. Irritable bowel syndrome patients with constipation may receive benefit from fibre treatment (relative risk, 1.56; 95% CI, 1.21-2.02), but there was no evidence that fibre was effective in the relief of abdominal pain in irritable bowel syndrome. Soluble and insoluble fibre, separately, had different effects on global irritable bowel syndrome symptoms. Soluble fibre (psyllium, ispaghula, calcium polycarbophil) showed significant improvement (relative risk, 1.55; 95% CI, 1.35-1.78), whereas insoluble fibre (corn, wheat bran), in some cases, worsened the clinical outcome, but there was no significant difference compared with placebo (relative risk, 0.89; 95% CI, 0.72-1.11).

CONCLUSIONS

The benefits of fibre in the treatment of irritable bowel syndrome are marginal for global irritable bowel syndrome symptom improvement and irritable bowel syndrome-related constipation. Soluble and insoluble fibres have different effects on global irritable bowel syndrome symptoms. Indeed, in some cases, insoluble fibres may worsen the clinical outcome. Future clinical studies evaluating the effect and tolerability of fibre therapy are needed in primary care.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common 'functional' gastrointestinal disorders accounting for 3% of all primary care consultations, with a strong female predominance. Although most of the literature comes from Western industrialized societies, when it has been looked for, this disorder appears to be equally common in the Third World. It is characterized by chronic abdominal pain or discomfort associated with disordered bowel habit and visceral hypersensitivity. Anxiety and somatization are more common in IBS than in the general population and may encourage consultation; however, they correlate poorly with symptoms. Bacterial gastroenteritis may be followed by the development of IBS in 5-10% of patients, depending on the severity of initial illness and prior anxiety or depression. The Rome criteria allow reliable diagnosis provided that there are no 'alarm' features which mandate further investigation. Microscopic colitis and bile salt malabsorption can easily be mistaken for IBS, as can chronic infestations or infections which should be considered, while recognizing that these are extremely uncommon in westernized societies. Some patients respond to exclusion diets as lactose and wheat intolerance are common. Others with prominent anxiety and/or depression respond to psychotherapy or antidepressants. Diarrhoeal symptoms respond to loperamide and 5HT3 receptor antagonists, while constipation responds to 5HT4 agonists. Antispasmodics may have limited benefit in treating pain. Low-dose tricyclic antidepressants are also helpful in alleviating pain and anxiety, even in those without obvious psychiatric disorders. If diagnostic criteria are met, then once diagnosed, new diagnoses rarely appear.

Food Intolerance: Dietary Treatments in Functional Bowel Disorders

Currently, there is little convincing scientific evidence from well-designed trials to support the role of dietary modification or exclusions in irritable bowel syndrome (IBS). Similarly, there is an absence of conclusive data linking any dietary components directly to the pathogenesis of IBS. The role of diet, as a single modality, is unlikely to play a major role in treating IBS. Dietary modifications should be viewed as a valuable part of a multicomponent management approach in combination with other strategies such as lifestyle, behavioral, and pharmacologic therapy.

Treatment of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is an extremely common cause of consultation, and at present is diagnosed on the basis of symptoms and a few simple exclusion tests. Exclusion diets can be successful, but many patients have already attempted and failed such treatments before consulting. Anxiety and somatization may be an important driver of consultation. Patients' concerns should be understood and addressed. Those with prominent psychiatric disease may benefit from psychotherapy. Hypnotherapy benefits symptoms in those without psychologic disturbance, but its availability is limited. Antidepressants are effective in improving both mood and IBS symptoms globally, and the evidence is particularly good for tricyclic antidepressants. Although antispasmodics are currently the most commonly prescribed drugs, most responses (75%) are due to the placebo effect and not specific to the drug. Bulk laxatives such as ispaghula can increase stool frequency and help pain, but bloating may be aggravated. Loperamide is effective treatment for urgency and loose stools, but less effective for bloating and pain. 5-HT(3) antagonists such as alosetron improve urgency, stool consistency, and pain in diarrhea-predominant-IBS. The 5-HT(4) agonist tegaserod shows modest benefit in constipation-predominant IBS, improving stool frequency, consistency, and bloating as well as global improvement. There are many new drugs, such as cholecystokinin, neurokinin, and corticotropin receptor antagonists, in development.

Abnormalities of GI transit in bloated irritable bowel syndrome: effect of bran on transit and symptoms

OBJECTIVES

Bloating is an important but poorly understood symptom in irritable bowel syndrome (IBS) that is often aggravated by bran. The aim of our study was to determine whether IBS patients with bloating responded to bran differently from healthy controls.

METHODS

A total of 12 patients with IBS (according to Rome I criteria), all with moderate to severe bloating, and 12 healthy controls participated in a two way, double blind, randomized, cross-over trial of bran versus placebo (crushed biscuits) 15 g b.i.d. An average daily pain index and bloating score were derived from daily symptom diaries. On day 14, gastric emptying, small bowel transit, percent remaining in ascending colon, and geometric center of a meal marker at 24 h were calculated from scintigraphic images obtained after ingesting a Tc99m-labeled rice pudding meal with 15 g of either placebo or coarse bran.

RESULTS

Results are given as median (range). Bran significantly increased the pain index and bloating (p < 0.02) in IBS patients but not controls. The most striking finding was that the small bowel transit time of the meal without bran was markedly faster in IBS patients than in controls, being 203 min (range 109-313) versus 367 min (219-543), p < 0.001. Although in controls bran accelerated small bowel transit time to 262 min (180-380), p = 0.03, and significantly reduced % remaining in the ascending colon from 22% (0-46) to 3% (0-25), p = 0.03, this was not seen in the IBS patients. Bran accelerated whole gut transit as assessed by geometric center at 24 h in both IBS patients and controls.

CONCLUSIONS

Bran accelerates small bowel transit and ascending colon clearance without causing symptoms in controls. Small bowel transit is rapid in IBS patients with bloating and, unlike in healthy control subjects, cannot be further accelerated by bran, which nevertheless aggravates symptoms of pain and bloating. We speculate that bran-induced bloating may originate in the colon rather than the small bowel.

Clinical perspectives, mechanisms, diagnosis and management of irritable bowel syndrome

This consensus document reviews the current status of the epidemiology, social impact, patient quality of life, pathophysiology, diagnosis and treatment of irritable bowel syndrome. Current evidence suggests that two major mechanisms may interact in irritable bowel syndrome: altered gastrointestinal motility and increased sensitivity of the intestine. However, other factors, such as psychosocial factors, intake of food and prior infection, may contribute to its development. Management of patients is based on a positive diagnosis of the symptom complex, careful history and physical examination to exclude 'red flags' as risk factors for organic disease, and, if indicated, investigations to exclude other disorders. Therapeutic choices include dietary fibre for constipation, opioid agents for diarrhoea and low-dose antidepressants or infrequent use of antispasmodics for pain, although the evidence basis for efficacy is limited or in some cases absent. Psychotherapy and hypnotherapy are the subject of ongoing study. Treatment should be tailored to patient needs and fears. Novel therapies are emerging, and drugs acting on serotonin receptors have proven efficacy and a scientific rationale and, if approved, should be useful in the overall management of patients with irritable bowel syndrome. Patient and physician education, early identification of psychosocial issues and better therapies are important strategies to reduce the suffering and societal cost of irritable bowel syndrome.

Diet in the irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) often request dietary recommendations. They must eat, and they want to know what to eat. Present national guidelines recommend dietary treatment with fiber for IBS patients with constipation. Diet recommendations are made based on symptoms. There may be different dietary recommendations for constipation, diarrhea, and pain or bloating. This article reviews the relationship of foods to IBS and issues of food intolerances and hypersensitivities, and recommendations for diet therapy. The role of dietary fiber, both soluble and insoluble, is reviewed. Although there are few studies to substantiate exact diets, broad dietary plans are recommended for the different symptoms of IBS. In addition, the recent literature on probiotics and prebiotics pertinent to IBS is reviewed.