The low FODMAP diet improves gastrointestinal symptoms in patients with irritable bowel syndrome: a prospective study

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.

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols: role in irritable bowel syndrome

Irritable bowel syndrome (IBS) was previously left poorly treated despite its high prevalence and cost. Over the past decade, significant research has been conducted providing new dietary strategies for IBS management. The 'low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet' has shown symptom improvement in 68-76% of patients. Randomized, controlled trials have now proven its efficacy. The diet, low in poorly absorbed and fermentable carbohydrates, uses dietary restriction and re-challenge to determine individual tolerance to various short-chain carbohydrates. However there may be potential detrimental effects of the diet in the long term, due to potential changes to the gastrointestinal microbiota. Appropriate dietary education and management of the diet is imperative. Future research should focus on the relevance of changes to the microbiota and ways to liberalize the dietary restrictions.

Fructose malabsorption is not uncommon among patients with irritable bowel syndrome in India: a case-control study

BACKGROUND

Fructose malabsorption (FM) is reported in 38 % to 75 % patients with irritable bowel syndrome (IBS). Most of these studies, however, had limitations due to use of variable dose of fructose, small sample size, and lack of control population. Moreover, there is no study on this issue from India. Hence, in this prospective study, we evaluated the frequency of FM on an adequately powered sample of patients with IBS and healthy controls (HC) from India.

METHODS

Ninety-seven patients with IBS (diagnosed using Rome III criteria) and 41 healthy controls were evaluated for FM by fructose hydrogen breath test (FHBT) using 25 g fructose. Persistent rise (at least two readings) in breath hydrogen 20 parts per million (PPM) above basal was considered diagnostic of FM.

RESULTS

Patients and controls were comparable in age (37 years [21-66] vs. 33 years [15-56]; p = 0.1) and gender (76/97 [78.4 %] vs. 29/41 [70.7 %] male; p = 0.3). Of 70 patients reporting data on Bristol's stool forms, 10 (14 %), 43 (61 %), and 17 (25 %) had constipation, diarrhea predominant and unclassified IBS (Asian classification), respectively. Patients with IBS more often had FM than controls on FHBT (14/97 [14.4 %] vs. 1/41 [2.4 %]; p = 0.04). Patients with FM more often had diarrhea-predominant IBS than those without FM (10/11 [91 %] vs. 33/59 [56 %]; p = 0.02).

CONCLUSION

Though FM was not very common among Indian patients with IBS, it was higher among them than controls. Patients with FM more often had diarrhea-predominant IBS.

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.

Breath tests and irritable bowel syndrome

Breath tests are non-invasive tests and can detect H₂ and CH₄ gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H₂ breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients.

Ehealth monitoring in irritable bowel syndrome patients treated with low fermentable oligo-, di-, mono-saccharides and polyols diet

In the present study we report on changes in irritable bowel syndrome-severity scoring system (IBS-SSS) and irritable bowel syndrome-quality of life (IBS-QoL) in 19 IBS patients, aged 18 to 74 years (F/M: 14/5), during 12 wk registering their symptoms on the web-application (www.ibs.constant-care.dk). During a control period of the first 6-wk patients were asked to register their IBS-SSS and IBS-QoL on the web-application weekly without receiving any intervention. Thereafter, low fermentable oligo-, di-, mono-saccharides and polyols (FODMAP) diet (LFD) was introduced for the next 6 wk while continuing the registration. Though a small sample size a significant improvement in disease activity (IBS-SSS) was observed during both the control period, median: 278 (range: 122-377), P = 0.02, and subsequently during the LFD period, median: 151 (range: 29-334), P < 0.01. The IBS-QoL solely changed significantly during the LFD period, median: 67 (37-120), P < 0.01. The significant reduction in disease activity during the control period shows a positive effect of the web-application on IBS symptoms when presented as a “traffic light”. However adding the diet reduced IBS-SSS to < 150, inactive to mild symptoms. In the future results from larger scale trials are awaited.

Functional bowel symptoms and diet

It is well recognised that ingestion of food is a trigger for functional bowel symptoms, particularly those associated with irritable bowel syndrome (IBS). Patients often use manipulation of diet as a means of controlling symptoms. Despite description of multiple dietary methods, few have scientific backing or quality evidence of efficacy. One approach is to define how specific food components influence the pathophysiology of IBS and then rationally design dietary approaches. For example, short-chain poorly absorbed carbohydrates (fermentable oligo-, di- and mono-saccharides and polyols (FODMAP)) cause luminal distension, which is a major stimulus for the development of symptoms in patients with visceral hypersensitivity. By determining food content of FODMAP, a diet in which foods low in FODMAP are favoured over those high in FODMAP can be designed. Observational, comparative and randomised controlled treatment and rechallenge studies have shown that such an approach is efficacious in the majority of patients with IBS. The low FODMAP diet is now the primary dietary therapy for such patients. Similar approaches can be applied to other food components, including proteins (such as gluten), fats and natural bioactive food chemicals. Such approaches have suggestions of efficacy, but the evidence base remains underdeveloped. An additional and important consideration for any dietary therapy is its nutritional adequacy and potential adverse health effects. Dietary manipulation is now a key management strategy in patients with functional bowel symptoms. Future well-designed interventional studies will lead to refinement of dietary approaches taken and to a better understanding of their long-term safety.

Irritable bowel syndrome in children: pathogenesis, diagnosis and evidence-based treatment

Irritable bowel syndrome (IBS) is the commonest cause of recurrent abdominal pain (RAP) in children in both more developed and developing parts of the world. It is defined by the Rome III criteria for functional gastrointestinal disorders. It is characterized by abdominal pain that is improved by defecation and whose onset is associated with a change in stool form and or frequency and is not explained by structural or biochemical abnormalities. It is estimated that 10%-15% of older children and adolescents suffer from IBS. IBS can be considered to be a brain-gut disorder possibly due to complex interaction between environmental and hereditary factors. The diagnosis of IBS is made based on the Rome III criteria together with ruling out organic causes of RAP in children such as inflammatory bowel disease and celiac disease. Once the diagnosis of IBS is made, it is important to explain to the parents (and children) that there is no serious underlying disease. This reassurance may be effective treatment in a large number of cases. Lifestyle modifications, stress management, dietary interventions and probiotics may be beneficial in some cases. Although there is limited evidence for efficacy of pharmacological therapies such as antispasmodics and antidiarrheals; these have a role in severe cases. Biopsychosocial therapies have shown encouraging results in initial trials but are beset by limited availability. Further research is necessary to understand the pathophysiology and provide specific focused therapies.

Mechanisms and efficacy of dietary FODMAP restriction in IBS

IBS is a debilitating condition that markedly affects quality of life. The chronic nature, high prevalence and associated comorbidities contribute to the considerable economic burden of IBS. The pathophysiology of IBS is not completely understood and evidence to guide management is variable. Interest in dietary intervention continues to grow rapidly. Ileostomy and MRI studies have demonstrated that some fermentable carbohydrates increase ileal luminal water content and breath hydrogen testing studies have demonstrated that some carbohydrates also increase colonic hydrogen production. The effects of fermentable carbohydrates on gastrointestinal symptoms have also been well described in blinded, controlled trials. Dietary restriction of fermentable carbohydrates (popularly termed the 'low FODMAP diet') has received considerable attention. An emerging body of research now demonstrates the efficacy of fermentable carbohydrate restriction in IBS; however, limitations still exist with this approach owing to a limited number of randomized trials, in part due to the fundamental difficulty of placebo control in dietary trials. Evidence also indicates that the diet can influence the gut microbiota and nutrient intake. Fermentable carbohydrate restriction in people with IBS is promising, but the effects on gastrointestinal health require further investigation.

Pediatric IBS: an overview on pathophysiology, diagnosis and treatment

Irritable bowel syndrome (IBS) is a common disorder in children and adults. The pathogenesis and pathophysiology of IBS remains incompletely understood. The biopsychosocial model, which conceptualizes chronic pain as a dysregulation of the gut-brain-homeostasis with peripheral and central factors mutually influencing each other, is the most accepted framework to explain IBS. Twin and family aggregation studies suggest a genetic component that does not exclusively explain the higher prevalence of IBS in certain families. Social learning (environmental factors) and maladaptive coping predispose children to develop IBS with greater disability and more frequent medical consultations. Early-life events constitute an additional risk factor for the development of IBS and other functional gastrointestinal disorders (FGIDs). Children with a history of cow's milk protein hypersensitivity or abdominal surgeries have a higher prevalence of IBS and other FGIDs years later. IBS frequently follows an episode of acute gastrointestinal inflammation (infectious or non-infectious). This article discusses the importance, known pathophysiological mechanisms, clinical approach, and evidence-based therapeutic options for the management of IBS in children and adolescents.

Popular exclusionary diets for inflammatory bowel disease: the search for a dietary culprit

The evolving understanding of the role of the microbiome and environmental factors in the pathogenesis of inflammatory bowel disease makes diet an interesting and potentially powerful tool in the treatment of disease. However, at this time, evidence is limited but anecdotal reports of success abound. There is a bewildering array of new diets being tried by patients in an attempt to control diseases. This review attempts to summarize the most common diets for the treating physician.

Irritable bowel syndrome: Emerging paradigm in pathophysiology

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, characterized by abdominal pain, bloating, and changes in bowel habits. These symptoms cannot be explained by structural abnormalities and there is no specific laboratory test or biomarker for IBS. Therefore, IBS is classified as a functional disorder with diagnosis dependent on the history taking about manifested symptoms and careful physical examination. Although a great deal of research has been carried out in this area, the pathophysiology of IBS is complex and not completely understood. Multiple factors are thought to contribute to the symptoms in IBS patients; altered gastrointestinal motility, visceral hypersensitivity, and the brain-gut interaction are important classical concepts in IBS pathophysiology. New areas of research in this arena include inflammation, postinfectious low-grade inflammation, genetic and immunologic factors, an altered microbiota, dietary factors, and enteroendocrine cells. These emerging studies have not shown consistent results, provoking controversy in the IBS field. However, certain lines of evidence suggest that these mechanisms are important at least a subset of IBS patients, confirming that IBS symptoms cannot be explained by a single etiological mechanism. Therefore, it is important to keep in mind that IBS requires a more holistic approach to determining effective treatment and understanding the underlying mechanisms.

[Importance of diet in irritable bowel syndrome]

About two-thirds of irritable bowel syndrome (IBS) patients associate their symptoms with certain foods. We reviewed food-related factors putatively associated with manifestations of IBS. Soluble fiber may improve constipation but frequently increases bloating and abdominal pain. Carbohydrate malabsorption seems to be more frequent in IBS. A low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet significantly reduces IBS symptoms and has been suggested as a therapeutic option. Serological screening for celiac disease should be done in patients without constipation. Moreover, non-celiac disease gluten sensitivity, defined as gluten intolerance once celiac disease and wheat allergy have been ruled out, should be considered in these patients. There is no specific diet for IBS patients but small and frequent meals, avoiding greasy foods, dairy products, many carbohydrates, caffeine and alcohol, is recommended.

Effect of gluten free diet on immune response to gliadin in patients with non-celiac gluten sensitivity

BACKGROUND

Non-celiac gluten sensitivity is a syndrome characterized by gastrointestinal and extra-intestinal symptoms occurring in a few hours/days after gluten and/or other wheat protein ingestion and rapidly improving after exclusion of potential dietary triggers. There are no established laboratory markers for non-celiac gluten sensitivity, although a high prevalence of first generation anti-gliadin antibodies of IgG class has been reported in this condition. This study was designed to characterize the effect of the gluten-free diet on anti-gliadin antibodies of IgG class in patients with non-celiac gluten sensitivity.

METHODS

Anti-gliadin antibodies of both IgG and IgA classes were assayed by ELISA in 44 non-celiac gluten sensitivity and 40 celiac disease patients after 6 months of gluten-free diet.

RESULTS

The majority of non-celiac gluten sensitivity patients (93.2%) showed the disappearance of anti-gliadin antibodies of IgG class after 6 months of gluten-free diet; in contrast, 16/40 (40%) of celiac patients displayed the persistence of these antibodies after gluten withdrawal. In non-celiac gluten sensitivity patients anti-gliadin antibodies IgG persistence after gluten withdrawal was significantly correlated with the low compliance to gluten-free diet and a mild clinical response.

CONCLUSIONS

Anti-gliadin antibodies of the IgG class disappear in patients with non-celiac gluten sensitivity reflecting a strict compliance to the gluten-free diet and a good clinical response to gluten withdrawal.

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.

Dietary fructose intolerance, fructan intolerance and FODMAPs

Dietary intolerances to fructose, fructans and FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are common, yet poorly recognized and managed. Over the last decade, they have come to the forefront because of new knowledge on the mechanisms and treatment of these conditions. Patients with these problems often present with unexplained bloating, belching, distension, gas, abdominal pain, or diarrhea. Here, we have examined the most up-to-date research on these food-related intolerances, discussed controversies, and have provided some guidelines for the dietary management of these conditions. Breath testing for carbohydrate intolerance appears to be standardized and essential for the diagnosis and management of these conditions, especially in the Western population. While current research shows that the FODMAP diet may be effective in treating some patients with irritable bowel syndrome, additional research is needed to identify more foods items that are high in FODMAPs, and to assess the long-term efficacy and safety of dietary interventions.

Factors associated with physical and cognitive fatigue in patients with Crohn's disease: a cross-sectional and longitudinal study

BACKGROUND

Fatigue commonly impairs quality of life in patients with Crohn's disease (CD). This study aimed to evaluate the prevalence and severity of fatigue in CD (compared with ulcerative colitis [UC] and healthy controls) and to identify potentially modifiable factors associated with global, physical, and cognitive dimensions of fatigue.

METHODS

Clinic attendees with confirmed CD or UC and healthy volunteers were surveyed on fatigue (Fatigue Impact Scale, FIS), psychological comorbidity, sleep quality, medication, and other clinical information. A CD subgroup also completed a similar follow-up survey.

RESULTS

In 379 responders (181 CD, 113 UC, and 85 controls), global, physical, and cognitive FIS scores were highest in CD followed by UC and controls (P < 0.01), with a prevalence of global fatigue (total FIS ≥ 40) in 57% of CD patients. On multivariate analysis, concurrently active disease, poor sleep quality, and mental illness were significantly associated with all the 3 fatigue dimensions: regular vitamin B group supplementation was inversely associated with physical fatigue in the CD cohort and those of older age or with previous resection(s) (P = 0.05) were independently associated with cognitive fatigue only. Longitudinally in CD, fatigue scores remained constant between original and follow-up surveys (mean change in total FIS score +0.9; 95% confidence interval, -4.6 to 6.3). Factors independently associated with improved physical fatigue between surveys included avoidance of corticosteroids and establishment of regular exercise and with improved cognitive fatigue included cessation of immunomodulator therapy.

CONCLUSIONS

Fatigue is highly prevalent and more severe in CD. Anticipated and novel associations with improvement of physical and/or cognitive fatigue were identified, offering clues to potential therapeutic approaches to ameliorating fatigue for clinical evaluation.

Differential effects of FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols) on small and large intestinal contents in healthy subjects shown by MRI

OBJECTIVES

The objective of this study was to investigate whether ingestion of fructose and fructans (such as inulin) can exacerbate irritable bowel syndrome (IBS) symptoms. The aim was to better understand the origin of these symptoms by magnetic resonance imaging (MRI) of the gut.

METHODS

A total of 16 healthy volunteers participated in a four-way, randomized, single-blind, crossover study in which they consumed 500 ml of water containing 40 g of either glucose, fructose, inulin, or a 1:1 mixture of 40 g glucose and 40 g fructose. MRI scans were performed hourly for 5 h, assessing the volume of gastric contents, small bowel water content (SBWC), and colonic gas. Breath hydrogen (H2) was measured and symptoms recorded after each scan.

RESULTS

Data are reported as mean (s.d.) (95% CI) when normally distributed and median (range) when not. Fructose increased area under the curve (AUC) from 0-5 h of SBWC to 71 (23) l/min, significantly greater than for glucose at 36 (11-132) l/min (P<0.001), whereas AUC SBWC after inulin, 33 (17-106) l/min, was no different from that after glucose. Adding glucose to fructose decreased AUC SBWC to 55 (28) l/min (P=0.08) vs. fructose. Inulin substantially increased AUC colonic gas to 33 (20) l/min, significantly greater than glucose and glucose+fructose (both P<0.05). Breath H2 rose more with inulin than with fructose. Glucose when combined with fructose significantly reduced breath H2 by 7,700 (3,121-12,300) p.p.m./min relative to fructose alone (P<0.01, n=13).

CONCLUSIONS

Fructose but not inulin distends the small bowel with water. Adding glucose to fructose reduces the effect of fructose on SBWC and breath hydrogen. Inulin distends the colon with gas more than fructose, but causes few symptoms in healthy volunteers.

Abdominal bloating: pathophysiology and treatment

Abdominal bloating is a very common and troublesome symptom of all ages, but it has not been fully understood to date. Bloating is usually associated with functional gastrointestinal disorders or organic diseases, but it may also appear alone. The pathophysiology of bloating remains ambiguous, although some evidences support the potential mechanisms, including gut hypersensitivity, impaired gas handling, altered gut microbiota, and abnormal abdominal-phrenic reflexes. Owing to the insufficient understanding of these mechanisms, the available therapeutic options are limited. However, medical treatment with some prokinetics, rifaximin, lubiprostone and linaclotide could be considered in the treatment of bloating. In addition, dietary intervention is important in relieving symptom in patients with bloating.