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

Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date

This review summarizes the published clinical studies concerning the management of irritable bowel syndrome (IBS) using restriction of Fermentable Oligosaccharide, Disaccharide, Monosaccharide, and Polyols in the diet (low FODMAP diet). In recent years, the data supporting low FODMAP diet for the management of IBS symptoms have emerged, including several randomized controlled trials, case-control studies, and other observational studies. Unlike most dietary manipulations tried in the past to alleviate gastrointestinal symptoms of IBS, all studies on low FODMAP diet have consistently shown symptomatic benefits in the majority of patients with IBS. However, dietary adherence by the patients and clear dietary intervention led by specialized dietitians appear to be vital for the success of the diet. Up to 86% of patients with IBS find improvement in overall gastrointestinal symptoms as well as individual symptoms such as abdominal pain, bloating, constipation, diarrhea, abdominal distention, and flatulence following the diet. FODMAP restriction reduces the osmotic load and gas production in the distal small bowel and the proximal colon, providing symptomatic relief in patients with IBS. Long-term health effects of a low FODMAP diet are not known; however, stringent FODMAP restriction is not recommended owing to risks of inadequate nutrient intake and potential adverse effects from altered gut microbiota. In conclusion, the evidence to date strongly supports the efficacy of a low FODMAP diet in the treatment of IBS. Further studies are required to understand any potential adverse effects of long-term restriction of FODMAPs.

Visceral hypersensitive rats share common dysbiosis features with irritable bowel syndrome patients

AIM

To evaluate gut microbial dysbiosis in two visceral hypersensitive models in comparison with irritable bowel syndrome (IBS) patients and to explore the extent to which these models capture the dysbiosis of IBS patients.

METHODS

Visceral hypersensitivity was developed using the maternal separation (MS) rat model and post-inflammatory rat model. The visceral sensitivity of the model groups and control group was evaluated using the abdominal withdraw reflex score and electromyography in response to graded colorectal distention. The 16S ribosomal RNA gene from fecal samples was pyrosequenced and analyzed. The correlation between dysbiosis in the microbiota and visceral hypersensitivity was calculated. Positive findings were compared to sequencing data from a published human IBS cohort.

RESULTS

Dysbiosis triggered by neonatal maternal separation was lasting but not static. Both MS and post-inflammatory rat fecal microbiota deviated from that of the control rats to an extent that was larger than the co-housing effect. Two short chain fatty acid producing genera, Fusobacterium and Clostridium XI, were shared by the human IBS cohort and by the maternal separation rats and post-inflammatory rats, respectively, to different extents. Fusobacterium was significantly increased in the MS group, and its abundance positively correlated with the degree of visceral hypersensitivity. Porphyromonadaceae was a protective biomarker for both the rat control group and healthy human controls.

CONCLUSION

The dysbiosis MS rat model and the post-inflammatory rat model captured some of the dysbiosis features of IBS patients. Fusobacterium, Clostridium XI and Porphyromonadaceae were identified as targets for future mechanistic research.

Complex Relationships Between Food, Diet, and the Microbiome

Diet is a risk factor in several medically important disease states, including obesity, celiac disease, and functional gastrointestinal disorders. Modification of diet can prevent, treat, or alleviate some of the symptoms associated with these diseases and improve general health. It is important to provide patients with simple dietary recommendations to increase the probability of successful implementation. These recommendations include increasing vegetable, fruit, and fiber intake, consuming lean protein sources to enhance satiety, avoiding or severely limiting highly processed foods, and reducing portion sizes for overweight and obese patients.

Integrative Nutrition for Pediatrics

Food is essential for life. Yet, poor food choices may cause poor health. Dietary manipulation is frequently integrated into the management of common chronic pediatric conditions. Parents seek dietary information to have more control over child's condition and to avoid side effects of medicine. This article reviews selected diets for a few common pediatric disorders including eczema, attention deficit hyperactivity disorder, headache and migraine, non-celiac gluten sensitivity, and irritable bowel syndrome.

Fermentable Carbohydrate Restriction (Low FODMAP Diet) in Clinical Practice Improves Functional Gastrointestinal Symptoms in Patients with Inflammatory Bowel Disease

BACKGROUND

A significant proportion of patients with inflammatory bowel disease (IBD) experience functional-like gastrointestinal symptoms (FGS) even during remission. Research suggests that dietary restriction of fermentable carbohydrates (low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet) can improve FGS, albeit in irritable bowel syndrome. The aim of this study was to investigate the effectiveness of the low FODMAP diet delivered in routine clinical practice in patients with IBD and coexisting FGS.

METHODS

Gastrointestinal symptom scores were compared in consecutive patients with IBD referred for low FODMAP dietary education for symptom management (n = 88). Symptoms were assessed using the Gastrointestinal Symptoms Rating Scale, and stool output was assessed using the Bristol Stool Form Scale at both baseline and follow-up (minimum of 6 weeks).

RESULTS

There was a significant and large increase in the numbers of patients reporting satisfactory relief of symptoms between baseline (14/88, 16%) and low FODMAP diet (69/88, 78%; P < 0.001). Following dietary intervention, there was also a significant decrease in severity for most symptoms and a reduction in composite symptom score (baseline mean: 1.2, SD: 0.5 versus low FODMAP diet mean: 0.7, SD: 0.5; P < 0.001). Improvements in stool consistency and frequency were observed, including an increase in "normal" stool form (P = 0.002) and "normal" stool frequency (P < 0.001).

CONCLUSIONS

The low FODMAP diet delivered in routine clinical practice seems effective in improving satisfaction with, and severity of, FGS in IBD. Randomized controlled trials are warranted to definitively establish effectiveness.

Addressing the Role of Food in Irritable Bowel Syndrome Symptom Management

Patients with irritable bowel syndrome (IBS) have often associated the worsening of symptoms with specific foods. Research is starting to catch up with what patients have reported about food interaction and their symptoms and the role of diet is being increasingly recognized for the management of IBS. Clinical guidance for nurse practitioners can be challenging due to limited data and guideline consensus along with the nuances of symptoms associated with IBS subtypes. This article summarizes some of the key themes and dietary recommendations by various gastrointestinal (GI) organizations, public health agencies, and dietary associations. By addressing the relevance of diet for symptom alleviation, nurse practitioners are able to better support patients and collaborate with dietitians to improve symptom management.

Pathogenic role of the gut microbiota in gastrointestinal diseases

The gastrointestinal (GI) tract is colonized by a dense community of commensal microorganisms referred to as the gut microbiota. The gut microbiota and the host have co-evolved, and they engage in a myriad of immunogenic and metabolic interactions. The gut microbiota contributes to the maintenance of host health. However, when healthy microbial structure is perturbed, a condition termed dysbiosis, the altered gut microbiota can trigger the development of various GI diseases including inflammatory bowel disease, colon cancer, celiac disease, and irritable bowel syndrome. There is a growing body of evidence suggesting that multiple intrinsic and extrinsic factors, such as genetic variations, diet, stress, and medication, can dramatically affect the balance of the gut microbiota. Therefore, these factors regulate the development and progression of GI diseases by inducing dysbiosis. Herein, we will review the recent advances in the field, focusing on the mechanisms through which intrinsic and extrinsic factors induce dysbiosis and the role a dysbiotic microbiota plays in the pathogenesis of GI diseases.

Follow-up of patients with functional bowel symptoms treated with a low FODMAP diet

AIM: To investigate patient-reported outcomes from, and adherence to, a low FODMAP diet among patients suffering from irritable bowel syndrome and inflammatory bowel disease.

METHODS: Consecutive patients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) and co-existing IBS fulfilling the ROME III criteria, who previously attended an outpatient clinic for low FODMAP diet (LFD) dietary management and assessment by a gastroenterologist, were invited to participate in a retrospective questionnaire analysis. The questionnaires were sent and returned by regular mail and gathered information on recall of dietary treatment, efficacy, symptoms, adherence, satisfaction, change in disease course and stool type, and quality of life. Before study enrolment all patients had to sign an informed written consent.

RESULTS: One hundred and eighty patients were included, 131 (73%) IBS and 49 (27%) IBD patients. Median age was 43 years (range: 18-85) and 147 (82%) were females. Median follow-up time was 16 mo (range: 2-80). Eighty-six percent reported either partial (54%) or full (32%) efficacy with greatest improvement of bloating (82%) and abdominal pain (71%). The proportion of patients with full efficacy tended to be greater in the IBD group than in the IBS group (42% vs 29%, P = 0.08). There was a significant reduction in patients with a chronic continuous disease course in both the IBS group (25%, P < 0.001) and IBD group (23%, P = 0.002) along with a significant increase in patients with a mild indolent disease course of 37% (P < 0.001) and 23% (P = 0.002), respectively. The proportion of patients having normal stools increased with 41% in the IBS group (P < 0.001) and 66% in the IBD group (P < 0.001). One-third of patients adhered to the diet and high adherence was associated with longer duration of dietary course (P < 0.001). Satisfaction with dietary management was seen in 83 (70%) IBS patients and 24 (55%) IBD patients. Eighty-four percent of patients lived on a modified LFD, where some foods rich in FODMAPs were reintroduced, and 16% followed the LFD by the book without deviations. Wheat, dairy products, and onions were the foods most often not reintroduced by patients.

CONCLUSION: These data suggest that a diet low in FODMAPs is an efficacious treatment solution in the management of functional bowel symptoms for IBS and IBD patients.

Consistent Prebiotic Effect on Gut Microbiota With Altered FODMAP Intake in Patients with Crohn's Disease: A Randomised, Controlled Cross-Over Trial of Well-Defined Diets

Objectives:

Altering FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) intake has substantial effects on gut microbiota. This study aimed to investigate effects of altering FODMAP intake on markers of colonic health in patients with Crohn's disease.

Methods:

After evaluation of their habitual diet, 9 patients with clinically quiescent Crohn's disease were randomised to 21 days of provided low or typical (“Australian”) FODMAP diets with ≥21-day washout in between. Five-day fecal samples were collected at the end of each diet and analyzed for calprotectin, pH, short-chain fatty acids (SCFA) and bacterial abundance. Gastrointestinal symptoms were recorded daily.

Results:

Eight participants collected feces and were adherent to the diets. FODMAP intake differed across the three dietary periods with low<habitual<Australian diet. SCFA, pH and total bacterial abundance remained unaltered, but relative abundance was higher for butyrate-producing Clostridium cluster XIVa (P=0.008) and mucus-associated Akkermansia muciniphila (P=0.016), and lower for Ruminococcus torques (P=0.034) during the Australian compared with low FODMAP diet. Results during habitual diet were similar to the low FODMAP intervention, but significantly different to the Australian diet. The diets had no effects on calprotectin, but symptoms doubled in severity with the Australian diet (n=9; P<0.001).

Conclusions:

In clinically quiescent Crohn's disease, altering dietary FODMAP intake is associated with marked changes in fecal microbiota, most consistent with a prebiotic effect of increasing FODMAPs as shown in an irritable bowel/healthy cohort. This strategy might be favorable for gut health in Crohn's disease, but at the cost of inducing symptoms.

Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis

BACKGROUND

Functional gastrointestinal symptoms such as abdominal pain, bloating, distension, constipation, diarrhea and flatulence have been noted in patients with irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). The diversity of symptoms has meant that finding an effective treatment has been challenging with most treatments alleviating only the primary symptom. A novel treatment option for IBS and IBD currently generating much excitement is the low fermentable, oligo-, di-, mono-saccharides and polyol (FODMAP) diet. The aim of this meta-analysis was to determine the evidence of the efficacy of such a diet in the treatment of functional gastrointestinal symptoms.

METHODS

Electronic databases were searched through to March 2015 to identify relevant studies. Pooled odds ratios (ORs) and 95 % confidence intervals were calculated for the effect of a low FODMAP diet on the reduction in IBS [Symptoms Severity Score (SSS)] score and increase in IBS quality of life (QOL) score for both randomized clinical trials (RCTs) and non-randomized interventions using a random-effects model.

RESULTS

Six RCTs and 16 non-randomized interventions were included in the analysis. There was a significant decrease in IBS SSS scores for those individuals on a low FODMAP diet in both the RCTs (OR 0.44, 95 % CI 0.25-0.76; I (2) = 35.52, p = 0.00) and non-randomized interventions (OR 0.03, 95 % CI 0.01-0.2; I (2) = 69.1, p = 0.02). In addition, there was a significant improvement in the IBS-QOL score for RCTs (OR 1.84, 95 % CI 1.12-3.03; I (2) = 0.00, p = 0.39) and for non-randomized interventions (OR 3.18, 95 % CI 1.60-6.31; I (2) = 0.00, p = 0.89). Further, following a low FODMAP diet was found to significantly reduce symptom severity for abdominal pain (OR 1.81, 95 % CI 1.13-2.88; I (2) = 0.00, p = 0.56), bloating (OR 1.75, 95 % CI 1.07-2.87; I (2) = 0.00, p = 0.45) and overall symptoms (OR 1.81, 95 % CI 1.11-2.95; I (2) = 0.00, p = 0.4) in the RCTs. In the non-randomized interventions similar findings were observed.

CONCLUSION

The present meta-analysis supports the efficacy of a low FODMAP diet in the treatment of functional gastrointestinal symptoms. Further research should ensure studies include dietary adherence, and more studies looking at greater number of patients and long-term adherence to a low FODMAP diet need to be conducted.

Macronutrient intakes in obese subjects with or without small intestinal bacterial overgrowth: an alimentary survey

OBJECTIVE

Obesity is a multifactorial disorder with a possible microbiota derangement in its pathogenesis. Moreover, in obese patients the likelihood of small intestinal bacterial overgrowth (SIBO) is greater than in controls, although few studies are currently available. This study investigates the prevalence of SIBO and the possible role of dietary macronutrients in obesity.

MATERIALS AND METHODS

Sixty obese patients and normal lean controls were enrolled for SIBO detection. Diagnosis of SIBO was performed by a glucose breath test. A 24-hour recall questionnaire was administered to investigate macronutrient daily intake between the two obese patient subgroups (with/without SIBO).

RESULTS

The presence of SIBO in obese and controls was respectively 23.3% and 6.6% (p = 0.02, OR = 4.26, 95% Confidence interval = 1.31-13.84). Obese patients with SIBO ingested more carbohydrates (252.75 ± 30.53 vs 201 ± 70.76 g/day, p = 0.01), more refined sugars (104.15 ± 28.69 vs 73.32 ± 44.93 g/day, p = 0.02) and less total and insoluble fibers (9.6 ± 1.97 vs 14.65 ± 8.80 g/day, p = 0.04 and 4.7 ± 1.11 vs 8.82 ± 5.80 g/day, p = 0.01, respectively). There were no significant differences in lipid and protein intake between the two groups.

CONCLUSIONS

SIBO is widespread in obese subjects. Carbohydrates might promote the development of SIBO in obesity and fibers provide a protective function. Our results suggest a close relationship between diet and SIBO in obesity, thus supporting a possible role for intestinal microbiota.

Fructose malabsorption

Incomplete intestinal absorption of fructose might lead to abdominal complaints such as pain, flatulence and diarrhoea. Whether defect fructose transporters such as GLUT5 or GLUT2 are involved in the pathogenesis of fructose malabsorption is a matter of debate. The hydrogen production by colonic bacteria is used for diagnosis with the hydrogen breath test. However, the appropriate fructose test dose for correct diagnosis is unclear. Subjects with fructose malabsorption show increased breath hydrogen levels and abdominal symptoms after fructose administration but do not report any symptoms when fructose is given together with glucose. This beneficial effect of glucose, however, cannot be explained yet but might be used for clinical care of these subjects.

Diagnosis and treatment of diarrhea-predominant irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders worldwide. The economic impact of IBS on the health care system is substantial, as is the personal impact on patients. Patients with diarrhea-predominant IBS (IBS-D) comprise a substantial proportion of the overall IBS population. Primary care providers are often the first point of contact for patients with IBS-D and can accurately diagnose IBS after a careful history and examination without extensive diagnostic tests. Several pharmacologic treatments (eg, loperamide, alosetron, and antidepressants) and non-pharmacologic treatments (eg, dietary modification and probiotics) are available for IBS-D, but restrictions on use (eg, alosetron) or the lack of controlled trial data showing reductions in both global and individual IBS-D symptoms (eg, bloating, pain and stool frequency) emphasize the need for alternative treatment options. Two newer medications (eluxadoline and rifaximin) were approved in May 2015 for the treatment of IBS-D, and represent new treatment options for this common gastrointestinal condition.

Diagnosis and treatment of diarrhea-predominant irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders worldwide. The economic impact of IBS on the health care system is substantial, as is the personal impact on patients. Patients with diarrhea-predominant IBS (IBS-D) comprise a substantial proportion of the overall IBS population. Primary care providers are often the first point of contact for patients with IBS-D and can accurately diagnose IBS after a careful history and examination without extensive diagnostic tests. Several pharmacologic treatments (eg, loperamide, alosetron, and antidepressants) and non-pharmacologic treatments (eg, dietary modification and probiotics) are available for IBS-D, but restrictions on use (eg, alosetron) or the lack of controlled trial data showing reductions in both global and individual IBS-D symptoms (eg, bloating, pain and stool frequency) emphasize the need for alternative treatment options. Two newer medications (eluxadoline and rifaximin) were approved in May 2015 for the treatment of IBS-D, and represent new treatment options for this common gastrointestinal condition.

Bifidobacterium and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder usually originated from gut dysfunction, and the mechanisms underlying IBS are not clear. IBS can seriously disrupt patient's normal routine, even though it is not life-threatening. With the development of high-throughput sequencing technology, a large number of studies have showed that intestinal flora imbalance does play an important role in the pathogenesis of IBS, especially Bifidobacterium. Bifidobacterium can resist the colonization and invasion of intestinal pathogenic bacteria, and enhance the intestinal epithelial barrier function. Besides, its metabolites also can improve the defense function of the intestinal tract. In the gut of patients with IBS, the number of Bifidobacteria is usually significantly reduced, suggesting that increasing the number of intestinal Bifidobacteria may play a positive role in the treatment of IBS. This paper summarizes the relationship between Bifidobacterium and IBS, and discusses the effect of Bifidobacterium in the adjuvant treatment of IBS.

Sensitivity to wheat, gluten and FODMAPs in IBS: facts or fiction?

IBS is one of the most common types of functional bowel disorder. Increasing attention has been paid to the causative role of food in IBS. Food ingestion precipitates or exacerbates symptoms, such as abdominal pain and bloating in patients with IBS through different hypothesised mechanisms including immune and mast cell activation, mechanoreceptor stimulation and chemosensory activation. Wheat is regarded as one of the most relevant IBS triggers, although which component(s) of this cereal is/are involved remain(s) unknown. Gluten, other wheat proteins, for example, amylase-trypsin inhibitors, and fructans (the latter belonging to fermentable oligo-di-mono-saccharides and polyols (FODMAPs)), have been identified as possible factors for symptom generation/exacerbation. This uncertainty on the true culprit(s) opened a scenario of semantic definitions favoured by the discordant results of double-blind placebo-controlled trials, which have generated various terms ranging from non-coeliac gluten sensitivity to the broader one of non-coeliac wheat or wheat protein sensitivity or, even, FODMAP sensitivity. The role of FODMAPs in eliciting the clinical picture of IBS goes further since these short-chain carbohydrates are found in many other dietary components, including vegetables and fruits. In this review, we assessed current literature in order to unravel whether gluten/wheat/FODMAP sensitivity represent 'facts' and not 'fiction' in IBS symptoms. This knowledge is expected to promote standardisation in dietary strategies (gluten/wheat-free and low FODMAP) as effective measures for the management of IBS symptoms.

Perceived food intolerance and irritable bowel syndrome in a population 3 years after a giardiasis-outbreak: a historical cohort study

Background

Studies have shown an increased prevalence of irritable bowel syndrome (IBS) after acute gastroenteritis. Food as a precipitating and perpetuating factor in IBS has gained recent interest, but food intolerance following gastroenteritis is less investigated. The aims of this study were firstly, to compare perceived food intolerance in a group previously exposed to Giardia lamblia with a control group; secondly, to explore the relation with IBS status; and thirdly, to investigate associations with content of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) in foods reported.

Methods

This is a historical cohort study with mailed questionnaire to 1252 Giardia exposed and a control cohort matched by gender and age. Differences between groups were investigated using bivariate and multivariate analyses.

Results

The questionnaire response rate in the exposed group was 65.3 % (817/1252) and in the control group 31.4 % (1128/3598). The adjusted odds ratio (OR) for perceived food intolerance for the exposed group was 2.00 with 95 % confidence interval (CI): 1.65 to 2.42, as compared with the control group. Perceived intolerance for dairy products was the most frequently reported intolerance, with an adjusted OR for the exposed of 1.95 (95 % CI: 1.51 to 2.51). Perceived intolerance for fatty foods, vegetables, fruit, cereals and alcohol was also significantly higher in the exposed group. The groups did not differ in perceived intolerance to spicy foods, coffee or soda. The association between exposure to Giardia infection and perceived food intolerance differed between the IBS group and the no-IBS group, but IBS was not a significant effect modifier for the association. Perceived intolerance for high FODMAP foods (adjusted OR 1.91) and low FODMAP foods (adjusted OR 1.55) was significantly associated with exposure status.

Conclusion

Exposure to Giardia infection was associated with perceived food intolerance 3 years after giardiasis. IBS status did not alter the association between exposure status and perceived food intolerance. Perceived intolerance to high FODMAP foods and low FODMAP foods were both statistically significantly associated with exposure to Giardia infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-015-0393-0) contains supplementary material, which is available to authorized users.

Low-FODMAP formula improves diarrhea and nutritional status in hospitalized patients receiving enteral nutrition: a randomized, multicenter, double-blind clinical trial

Background

Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) are poorly absorbed, short-chain carbohydrates that play an important role in inducing functional gut symptoms. A low-FODMAP diet improves abdominal symptoms in patients with inflammatory bowel disease and irritable bowel syndrome. However, there were no study for the effect of FODMAP content on gastrointestinal intolerance and nutritional status in patients receiving enteral nutrition (EN).

Methods

In this randomized, multicenter, double-blind, 14-day clinical trial, eligible hospitalized patients receiving EN (n = 100) were randomly assigned to three groups; 84 patients completed the trial (low-FODMAP EN, n = 30; moderate-FODMAP EN, n = 28; high-FODMAP EN, n = 26). Anthropometric and biochemical parameters were measured; stool assessment was performed using the King’s Stool Chart and clinical definition.

Results

Baseline values were not significantly different among the three groups. After the 14-day intervention, diarrhea significantly improved in the low-FODMAP group than in the moderate- and high-FODMAP groups (P < 0.05). King’s Stool scores in diarrhea subjects were significantly and steadily reduced in the low-FODMAP group compared with the other two groups (P for time and EN type interaction <0.05). BMI increased significantly in the low- and high-FODMAP groups during the intervention (P < 0.05 for both), and showed a trend toward increasing in the moderate-FODMAP group (P < 0.10). Serum prealbumin increased significantly in all groups by 14-day; by 3-day, it had increased to the levels at 14-day in the low-FODMAP group. At 14-day, serum transferrin had increased significantly in the moderate-FODMAP group. In addition, subjects were classified by final condition (unimproved, normal maintenance, diarrhea only improved, constipation only improved, and recurrent diarrhea/constipation improved). Seventy-five percent of the diarrhea improved group consumed the low-FODMAP EN formula. 38.5 and 46.2 % of recurrent diarrhea/constipation improved group consumed the low- and moderate-FODMAP EN respectively. BMI significantly increased in all groups except the unimproved. Prealbumin levels significantly increased in the diarrhea-improved and recurrent diarrhea/constipation groups at 3-day and continued by 14-day, and in the constipation-improved group at 14-day. Transferrin levels significantly increased in the diarrhea-improved and recurrent diarrhea/constipation groups at 14-day.

Conclusion

Low-FODMAP EN may improve diarrhea, leading to improved nutritional status and facilitating prompt recovery from illness.

Electronic supplementary material

The online version of this article (doi:10.1186/s12937-015-0106-0) contains supplementary material, which is available to authorized users.

The Science, Evidence, and Practice of Dietary Interventions in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a highly prevalent disorder that is characterized by symptoms of abdominal pain, bloating, constipation, and/or diarrhea. The diagnosis can be made using Rome III criteria or published guidelines after taking a thoughtful history, excluding warning signs, and performing a careful physical examination. Limited testing (ie, complete blood count and C-reactive protein level) may be useful in appropriate patients. A number of pharmacologic options are available, although many patients fail to respond to pharmacologic therapy. Although several IBS diets frequently are recommended, data supporting their use are limited. This article provides a rationale as to why specific diets might improve IBS symptoms and evaluates published trials.

The Low FODMAP Diet and Its Application in East and Southeast Asia

There is growing interest in using food choice/dietary change to influence clinical outcomes in patients with irritable bowel syndrome (IBS). The low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet is an evidence-based approach that is gaining popularity in many Western countries. The low FODMAP diet is based on restricting dietary intake of short chain carbohydrates that are slowly absorbed or indigestible and not absorbed during passage through the small intestine. These are collectively described as "FODMAPs" and comprise oligosaccharides (mostly fructans, galacto-oligosaccharides), sugar polyols, fructose in excess of glucose, and lactose in lactose malabsorbers. The general strategy of the diet is to avoid foods high in FODMAPs and replace them with foods low in FODMAPs, with long-term restriction limited to what is required to control symptoms. The likely mechanism of action is minimisation of the stimulation of mechanoreceptors exerted by distension of the intestinal lumen with water from osmotic effects and gases from bacterial fermentation in those with visceral hypersensitivity. The success of this dietary approach greatly depends on detailed knowledge about the FODMAP composition of food com - monly consumed in that country. While the content of foods associated with East and Southeast Asian cuisines has not been fully explored, major high FODMAP sources are frequently used and include onion, garlic, shallots, legumes/pulses, and wheat-based products. Thus, this dietary approach holds great promise in treating IBS patients in East and Southeast Asia. The aim of this review is to highlight how the diet is implemented, its efficacy, and troublesome ingredients frequently used in Asian dishes.

Role of FODMAPs in Patients With Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a condition characterized by abdominal pain, bloating, flatus, and altered bowel habits. The role of dietary components in inducing IBS symptoms is difficult to explore. To date, foods are not considered a cause but rather symptom-triggering factors. Particular interest has been given to the so-called FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols). We aimed to summarize the evidence from the most common approaches to manage suspected food intolerance in IBS, with a particular interest in the role of FODMAPs and the effects of a low FODMAP diet. We reviewed literature, consulting PubMed and Medline by using the search terms FODMAP(s), fructose, lactose, fructans, galactans, polyols (sorbitol, mannitol, maltitol, xylitol, erythritol, polydextrose, and isomalt), irritable bowel syndrome, and functional gastrointestinal symptoms. FODMAP-restricted diets have been used for a long time to manage patients with IBS. The innovation in the so-called FODMAP concept is that a global restriction should have a more consistent effect than a limited one in preventing abdominal distension. Even though all the potential low FODMAP diets provide good relief of symptoms in many patients, there is just a little relief in others. Several studies highlight the role of low FODMAP diets to improve symptoms in patients with IBS. The evidence on this dietary approach supports the hypothesis that a low FODMAP diet should be the first dietary approach. However, many points remain to be clarified, including the evaluation of possibly significant nutrition concerns.

Fructose Malabsorption in Systemic Sclerosis

The deleterious effect of fructose, which is increasingly incorporated in many beverages, dairy products, and processed foods, has been described; fructose malabsorption has thus been reported in up to 2.4% of healthy subjects, leading to digestive clinical symptoms (eg, pain, distension, diarrhea). Because digestive involvement is frequent in patients with systemic sclerosis (SSc), we hypothesized that fructose malabsorption could be responsible for intestinal manifestations in these patients. The aims of this prospective study were to: determine the prevalence of fructose malabsorption, in SSc; predict which SSc patients are at risk of developing fructose malabsorption; and assess the outcome of digestive symptoms in SSc patients after initiation of standardized low-fructose diet. Eighty consecutive patients with SSc underwent fructose breath test. All SSc patients also completed a questionnaire on digestive symptoms, and a global symptom score (GSS) was calculated. The prevalence of fructose malabsorption was as high as 40% in SSc patients. We also observed a marked correlation between the presence of fructose malabsorption and: higher values of GSS score of digestive symptoms (P = 0.000004); and absence of delayed gastric emptying (P = 0.007). Furthermore, in SSc patients with fructose malabsorption, the median value of GSS score of digestive symptoms was lower after initiation of standardized low-fructose diet (4 before vs. 1 after; P = 0.0009). Our study underscores that fructose malabsorption often occurs in SSc patients. Our findings are thus relevant for clinical practice, highlighting that fructose breath test is a helpful, noninvasive method by: demonstrating fructose intolerance in patients with SSc; and identifying the group of SSc patients with fructose intolerance who may benefit from low-fructose diet. Interestingly, because the present series also shows that low-fructose diet resulted in a marked decrease of gastrointestinal clinical manifestations in SSc patients with fructose malabsorption, our findings underscore that fructose malabsorption may play a significant role in the onset of gastrointestinal symptoms in these patients. Finally, we suggest that fructose malabsorption may be due to reduced fructose absorption by enterocytes, impaired enteric microbiome, and decreased intestinal permeability.

Clinical response in Mexican patients with irritable bowel syndrome treated with a low diet low in fermentable carbohydrates (FODMAP)

BACKGROUND

The low FODMAP diet eliminates carbohydrates and fermentable alcohols because they are not absorbed by the intestine, but are fermented by the microbiota, causing bloating and flatulence.

AIMS

To evaluate the clinical response to the low FODMAP diet in patients with the different clinical subtypes of irritable bowel syndrome (IBS).

MATERIALS AND METHODS

Patients attended to at the Gastroenterology Department in 2014 that were diagnosed with IBS based on the Rome III criteria were included in the study. They were managed with a low FODMAP diet for 21 days and their response to the symptoms of abdominal pain, bloating, flatulence, and stool form pre and post-diet were evaluated through the visual analogue scale, Bristol scale, and patient overall satisfaction. The results were analyzed by means, 95% CI, and the Student's t test.

RESULTS

Of the 31 patients included in the study, 87% were women and the mean age was 46.48 years. Distribution was: IBS-C 64.5%, IBS-D 22.6%, and IBS-M 12.9%. The score for pain was 6.0 (95% CI 5.04-6.96) and the post-diet score was 2.77 (95% CI 1.60-3.95) (P<.001). The score for bloating was 7.10 (95% CI 6.13-8.06) and the post-diet score was 4.19 (95% CI 2.95-5.44) (P<.001). The score for flatulence was 5.94 (95% CI 4.79-7.08) and the post-diet score was 3.06 (IC95% 1.99-4.14) (P<.001). The pre-diet Bristol Scale result was 3.68 (95% CI 3.14-4.22) and the post-diet result was 4.10 (95% CI 3.66-4.54) (P=.1). The satisfaction percentage was 70.9%.

CONCLUSIONS

In this first study on a Mexican population with IBS, there was significant improvement of the main symptoms, including pain, bloating, and flatulence after treatment with a low FODMAP diet.

Randomised clinical trial: gut microbiome biomarkers are associated with clinical response to a low FODMAP diet in children with the irritable bowel syndrome

BACKGROUND

A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet can ameliorate symptoms in adult irritable bowel syndrome (IBS) within 48 h.

AIM

To determine the efficacy of a low FODMAP diet in childhood IBS and whether gut microbial composition and/or metabolic capacity are associated with its efficacy.

METHODS

In a double-blind, crossover trial, children with Rome III IBS completed a 1-week baseline period. They then were randomised to a low FODMAP diet or typical American childhood diet (TACD), followed by a 5-day washout period before crossing over to the other diet. GI symptoms were assessed with abdominal pain frequency being the primary outcome. Baseline gut microbial composition (16S rRNA sequencing) and metabolic capacity (PICRUSt) were determined. Metagenomic biomarker discovery (LEfSe) compared Responders (≥50% decrease in abdominal pain frequency on low FODMAP diet only) vs. Nonresponders (no improvement during either intervention).

RESULTS

Thirty-three children completed the study. Less abdominal pain occurred during the low FODMAP diet vs. TACD [1.1 ± 0.2 (SEM) episodes/day vs. 1.7 ± 0.4, P < 0.05]. Compared to baseline (1.4 ± 0.2), children had fewer daily abdominal pain episodes during the low FODMAP diet (P < 0.01) but more episodes during the TACD (P < 0.01). Responders were enriched at baseline in taxa with known greater saccharolytic metabolic capacity (e.g. Bacteroides, Ruminococcaceae, Faecalibacterium prausnitzii) and three Kyoto Encyclopedia of Genes and Genomes orthologues, of which two relate to carbohydrate metabolism.

CONCLUSIONS

In childhood IBS, a low FODMAP diet decreases abdominal pain frequency. Gut microbiome biomarkers may be associated with low FODMAP diet efficacy. ClinicalTrials.gov identifier: NCT01339117.

Systematic review: dietary fibre and FODMAP-restricted diet in the management of constipation and irritable bowel syndrome

BACKGROUND

Dietary fibre supplements have been advocated for the management of chronic constipation (CC) and irritable bowel syndrome (IBS). Recently, a fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) restricted diet has been recommended for IBS.

AIM

To systematically examine recent evidence for dietary interventions with fibre in CC and IBS and FODMAP-restricted diet in IBS, and provide recommendations.

METHODS

We searched PUBMED, MEDLINE, OVID and COCHRANE databases from 2004 to 2014. Published studies in adults with CC and IBS and constipation-predominant IBS (IBS-C) that compared fibre with placebo/alternative and FODMAP-restricted diet with alternative were included.

RESULTS

Of 550 potentially eligible clinical trials on fibre, 11 studies were found and of 23 potentially eligible studies on FODMAPs, six were found. A meta-analysis was not performed due to heterogeneity and methodological quality. Fibre was beneficial in 5/7 studies in CC and 3/3 studies in IBS-C. FODMAP-restricted diet improved overall IBS symptoms in 4/4 and IBS-C symptoms in 1/3 studies and three studies did not meet inclusion criteria. There were significant disparities in subject selection, interventions and outcome assessments in both fibre and FODMAPs studies.

CONCLUSIONS

Fibre supplementation is beneficial in mild to moderate CC and IBS-C, although larger, more rigorous and long-term RCTs are needed (Fair evidence-Level II, Grade B). Although the FODMAP-restricted diet may be effective in short-term management of selected patients with IBS (Fair evidence-Level II, Grade C) and IBS-C (Poor evidence-Level III, Grade C), more rigorous trials are needed to establish long-term efficacy and safety, particularly on colonic health and microbiome.

A systematic review of adherence to restricted diets in people with functional bowel disorders

Functional bowel disorders such as irritable bowel syndrome are commonly experienced within the population, and have an adverse impact on emotions, physical well-being, social activity, and occupational output. Adherence to a restricted diet can reduce symptoms, which in turn leads to increased quality of life and well-being. The aim of this review was to assess the extent to which predictors of dietary adherence have been considered in studies relating to functional bowel disorders and following a restricted diet. This was done firstly by examining such studies which contained a measure or indicator of adherence, and then by examining predictors of adherence within and between studies. A search of PsycINFO, Medline, CINAHL, Web of Science, and Cochrane databases was performed during July 2014, with the search criteria including relevant terms such as gastrointestinal disorder, irritable bowel syndrome, diet, and adherence. Of an initial 7927 papers, 39 were suitable for inclusion. Fourteen of the 39 studies included had a structured measure or indicator of dietary adherence, and the remaining 25 mentioned adherence without any structured levels of adherence. There was little investigation into the predictors of adherence, with symptom relief or induction being the primary goal of most of the studies. This review indicates that predictors of dietary adherence are rarely considered in research regarding functional bowel disorders. Further investigation is needed into the variables which contribute to rates of adherence to restricted diets, and more rigorous research is needed to characterise those individuals most likely to be non-adherent. Such research is necessary to ensure that people with these conditions can be provided with appropriate support and interventions.

Low-FODMAP Diet for Irritable Bowel Syndrome: Is It Ready for Prime Time?

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disease, which adversely affects the quality of life. Its prevalence has been reported to be around 10-15 % in North America and constitutes the most common cause for gastroenterology referral. Unfortunately, the pathophysiology of IBS is not completely understood. Not surprisingly, the management strategies can leave the patients with inadequate symptom control, making IBS a debilitating gastrointestinal syndrome. Dietary interventions as a treatment strategy for IBS have been recently evaluated. One such intervention includes dietary restriction of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs). FODMAPs define a group of short-chain carbohydrates that are incompletely absorbed in small intestine and later fermented in the colon. Evidence in the form of randomized controlled trials and observational studies have evaluated the mechanism of action and efficacy of low-FODMAP diet. This dietary intervention has showed promising results in symptom reduction in IBS patients. However, latest trials have also shown that the low-FODMAP diet is associated with marked changes in gut microbiota specifically reduction in microbiota with prebiotic properties. Implications of such changes on gastrointestinal health need to be further evaluated in future trials.

Systematic review: noncoeliac gluten sensitivity

BACKGROUND

Noncoeliac gluten sensitivity (NCGS) is a controversial emerging disorder. Despite reported symptoms related to the ingestion of gluten, NCGS remains a diagnosis based on the exclusion of coeliac disease, given the absence of reliable biomarkers.

AIM

To evaluate the prevalence, diagnostic exclusion of coeliac disease and the efficacy of a gluten-free diet (GFD) for NCGS patients.

METHODS

A PubMed search was performed up to December 2014. According to consensus diagnostic criteria, NCGS was defined as self-reported gluten intolerance, negative coeliac serology and absence of villous atrophy. Studies evaluating the impact of a GFD on patients with irritable bowel syndrome (IBS) were also included.

RESULTS

Prevalence rates of NCGS (0.5-13%) differed widely. Seventeen studies, including 1561 patients (26 children), met the inclusion criteria for NCGS. HLA haplotypes could not be linked to histology [normal or lymphocytic enteritis (LE)] in 1123 NCGS patients. HLADQ2/DQ8 haplotypes were present in 44% of NCGS patients. After advanced diagnostic techniques in 189 NCGS patients combining LE and HLADQ2/DQ8 haplotypes, 39 (20%) were reclassified as coeliac disease. There was a higher than expected family history of coeliac disease and autoimmune disorders in NCGS patients. A GFD resulted in variable results for variable, but significantly improved stool frequency in HLADQ2 positive diarrhoea-predominant IBS patients.

CONCLUSIONS

Prevalence rates for NCGS are extremely variable. A subset of NCGS patients might belong in the so-called 'coeliac-lite' disease. The benefit of a GFD for NCGS patients is currently controversial. HLADQ2 positive diarrhoea-type IBS patients might gain symptom improvement from a GFD.

Food components and irritable bowel syndrome

Ingestion of food has long been linked with gut symptoms, and there is increasing interest in using diet in the management of patients with irritable bowel syndrome (IBS). The West has developed an intense interest in specialized, restrictive diets, such as those that target multiple food groups, avoid gluten, or reduce fermentable oligo-, di-, and mono-saccharides and polyols. However, most gastroenterologists are not well educated about diets or their effects on the gut. It is important to understand the various dietary approaches, their putative mechanisms, the evidence that supports their use, and the benefits or harm they might produce. The concepts behind, and delivery of, specialized diets differ from those of pharmacologic agents. High-quality research is needed to determine the efficacy of different dietary approaches and the place of specific strategies.

Coeliac disease and noncoeliac gluten sensitivity

The spectrum of gluten-related disorders was restricted to coeliac disease and wheat allergy, but the new contemporary entity referred to as noncoeliac gluten sensitivity has gained recognition mainly in adults but also in children. Noncoeliac gluten sensitivity is defined as the presence of a variety of symptoms related to gluten ingestion in patients in whom coeliac disease and wheat allergy have been excluded. The pathophysiology and biomarkers of coeliac disease and wheat allergy are well known, but this is not the case for noncoeliac gluten sensitivity. It is also not clear whether noncoeliac gluten sensitivity is caused by consumption of gluten or by consumption of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Randomized trials on noncoeliac gluten sensitivity in children are lacking and are hardly needed to evaluate its role in paediatric patients with gastroenterology to avoid the use of unnecessary restrictive diets in children and interference with proper diagnosis of coeliac disease.

Dietary management of IBD--insights and advice

The current general interest in the use of food choice or diet in maintaining good health and in preventing and treating disease also applies to patients with IBD, who often follow poor or nutritionally challenging dietary plans. Unfortunately, dietary advice plays only a minor part in published guidelines for management of IBD, which sends a message that diet is not of great importance. However, a considerable evidence base supports a focused and serious attention to nutrition and diet in patients with IBD. In this Review, a step-wise approach in the evaluation and management of these patients is proposed. First, dietary intake and eating habits as well as current nutritional state should be documented, and corrective measures instituted. Secondly, dietary strategies as primary or adjunctive therapy for the reduction of inflammation and/or prevention of relapse of IBD should be seriously contemplated. Thirdly, use of diet to improve symptoms or lessen the effects of complications should be considered. Finally, dietary advice regarding disease prevention should be discussed when relevant. An increasing need exists for applying improved methodologies into establishing the value of current and new ways of using food choice as a therapeutic and preventive tool in IBD.

A Grounded Guide to Gluten: How Modern Genotypes and Processing Impact Wheat Sensitivity

The role of wheat, and particularly of gluten protein, in our diet has recently been scrutinized. This article provides a summary of the main pathologies related to wheat in the human body, including celiac disease, wheat allergy, nonceliac wheat sensitivity, fructose malabsorption, and irritable bowel syndrome. Differences in reactivity are discussed for ancient, heritage, and modern wheats. Due to large variability among species and genotypes, it might be feasible to select wheat varieties with lower amounts and fewer types of reactive prolamins and fructans. Einkorn is promising for producing fewer immunotoxic effects in a number of celiac research studies. Additionally, the impact of wheat processing methods on wheat sensitivity is reviewed. Research indicates that germination and fermentation technologies can effectively alter certain immunoreactive components. For individuals with wheat sensitivity, less-reactive wheat products can slow down disease development and improve quality of life. While research has not proven causation in the increase in wheat sensitivity over the last decades, modern wheat processing may have increased exposure to immunoreactive compounds. More research is necessary to understand the influence of modern wheat cultivars on epidemiological change.

Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance

BACKGROUND

Food intolerance is non-immunological and is often associated with gastrointestinal symptoms.

AIM

To focus on food intolerance associated with gastrointestinal symptoms and critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence.

METHODS

A search using the terms and variants of food intolerance, lactose, FODMAP, gluten, food chemicals within Pubmed, Embase and Scopus was carried out and restricted to human studies published in English. Additionally, references from relevant papers were hand searched for other appropriate studies.

RESULTS

Food intolerance affects 15-20% of the population and may be due to pharmacological effects of food components, noncoeliac gluten sensitivity or enzyme and transport defects. There have been significant advances in understanding the scientific basis of gastrointestinal food intolerance due to short-chain fermentable carbohydrates (FODMAPs). The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction. A low FODMAP diet is effective, however, it affects the gastrointestinal microbiota and FODMAP reintroduction to tolerance is part of the management strategy.

CONCLUSIONS

There is increasing evidence for using a low FODMAP diet in the management of functional gastrointestinal symptoms where food intolerance is suspected. Exclusion diets should be used for as short a time as possible to induce symptom improvement, and should be followed by gradual food reintroduction to establish individual tolerance. This will increase dietary variety, ensure nutritional adequacy and minimise impact on the gastrointestinal microbiota.

Intestinal microbiota and diet in IBS: causes, consequences, or epiphenomena?

Irritable bowel syndrome (IBS) is a heterogeneous functional disorder with a multifactorial etiology that involves the interplay of both host and environmental factors. Among environmental factors relevant for IBS etiology, the diet stands out given that the majority of IBS patients report their symptoms to be triggered by meals or specific foods. The diet provides substrates for microbial fermentation, and, as the composition of the intestinal microbiota is disturbed in IBS patients, the link between diet, microbiota composition, and microbial fermentation products might have an essential role in IBS etiology. In this review, we summarize current evidence regarding the impact of diet and the intestinal microbiota on IBS symptoms, as well as the reported interactions between diet and the microbiota composition. On the basis of the existing data, we suggest pathways (mechanisms) by which diet components, via the microbial fermentation, could trigger IBS symptoms. Finally, this review provides recommendations for future studies that would enable elucidation of the role of diet and microbiota and how these factors may be (inter)related in the pathophysiology of IBS.

Ehealth: Low FODMAP diet vs Lactobacillus rhamnosus GG in irritable bowel syndrome

AIM: To investigate the effects of a low fermentable, oligosaccharides, disaccharides, monosaccharides and polyols diet (LFD) and the probiotic Lactobacillus rhamnosus GG (LGG) in irritable bowel syndrome (IBS).

METHODS: Randomised, unblinded controlled trial on the effect of 6-wk treatment with LFD, LGG or a normal Danish/Western diet (ND) in patients with IBS fulfilling Rome III diagnostic criteria, recruited between November 2009 and April 2013. Patients were required to complete on a weekly basis the IBS severity score system (IBS-SSS) and IBS quality of life (IBS-QOL) questionnaires in a specially developed IBS web self-monitoring application. We investigated whether LFD or LGG could reduce IBS-SSS and improve QOL in IBS patients.

RESULTS: One hundred twenty-three patients (median age 37 years, range: 18-74 years), 90 (73%) females were randomised: 42 to LFD, 41 to LGG and 40 to ND. A significant reduction in mean ± SD of IBS-SSS from baseline to week 6 between LFD vs LGG vs ND was revealed: 133 ± 122 vs 68 ± 107, 133 ± 122 vs 34 ± 95, P < 0.01. Adjusted changes of IBS-SSS for baseline covariates showed statistically significant reduction of IBS-SSS in LFD group compared to ND (IBS-SSS score 75; 95%CI: 24-126, P < 0.01), but not in LGG compared to ND (IBS-SSS score 32; 95%CI: 18-80, P = 0.20). IBS-QOL was not altered significantly in any of the three groups: mean ± SD in LFD 8 ± 18 vs LGG 7 ± 17, LFD 8 ± 18 vs ND 0.1 ± 15, P = 0.13.

CONCLUSION: Both LFD and LGG are efficatious in patients with IBS.

[The diet low in fermentable carbohydrates short chain and polyols improves symptoms in patients with functional gastrointestinal disorders in Spain]

BACKGROUND AND AIMS

Successful treatment of patients with irritable bowel syndrome (IBS) often remains elusive. Recent studies in Australia, the United Kingdom and New Zealand have suggested the efficacy of a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) in the management of these patients. The aims of this study were to determine whether a diet low in FODMAPs improves symptoms in patients with functional gastrointestinal disorders (FGID) in Spain and to analyze the predictors of a good response.

PATIENTS AND METHODS

A prospective study was carried out in consecutive patients with FGID type IBS and functioanl abdominal bloating. At inclusion all patients underwent an assessment through a baseline demographic questionnaire of symptoms of anxiety and depression and quality of life. A hydrogen breath test with lactose and fructose was performed and a low FODMAPs diet was indicated for 2 months by expert dietitians. These tests were taken as a reference. A positive response was defined as an improvement of at least 5 points out of a possible 10 in the symptom questionnaire.

RESULTS

We included 30 patients (24 women, 39 [12] years). The response to the low FODMAPs diet was positive in controlling overall symptoms and specific symptoms such as functioanl abdominal bloating, abdominal pain, diarrhea, flatulence, nausea and fatigue in more than 70% of patients (P<.05). By contrast, constipation was controlled in only 48% of patients (P>.05). Adherence to the diet was good in 87% of patients and was a predictor of positive response in the univariate analysis.

CONCLUSIONS

A diet low in FODMAPs is associated with symptom improvement in patients with IBS and functioanl abdominal bloating. Adherence to the diet was a determining factor.

Confocal endomicroscopy shows food-associated changes in the intestinal mucosa of patients with irritable bowel syndrome

BACKGROUND & AIMS

We investigated suspected food intolerances in patients with irritable bowel syndrome (IBS) using confocal laser endomicroscopy (CLE) for real-time visualization of structural/functional changes in the intestinal mucosa after food challenge. Patients with functional changes after food challenge (CLE+) were placed on personalized exclusion diets and followed up for long-term symptom relief.

METHODS

Thirty-six IBS patients with suspected food intolerance and 10 patients with Barrett's esophagus (controls) without IBS symptoms were examined by CLE at University Hospital Schleswig-Holstein (Kiel, Germany). Diluted food antigens were administered directly to the duodenal mucosa through the working channel of the endoscope. Epithelial breaks, intervillous spaces, and the number of intraepithelial lymphocytes (IEL) were measured before and after the food challenge. CLE+ patients were placed on exclusion diets, given symptom score questionnaires, and followed up for 1 year; controls resumed their previous diet.

RESULTS

CLE showed a real-time response to food antigens in 22 of 36 patients; no responses were observed in 14 of 36 patients (CLE-) or any of the controls. Baseline IELs were significantly higher in CLE+ than CLE- subjects (P = .004); numbers increased significantly after food challenge (P = .0008). Within 5 minutes of exposure of CLE+ patients to food antigens, IELs increased, epithelial leaks/gaps formed, and intervillous spaces widened. Epithelial leaks and intervillous spaces also increased significantly in CLE+ vs baseline (both P < .001). The concordance of IELs measured by CLE and conventional histology was 70.6%; they did not correlate (P = .89; r(2) = 0.027). Symptom scores improved more than 50% in CLE+ patients after a 4-week exclusion diet and increased to 74% at 12 months; symptoms continued in CLE- patients.

CONCLUSIONS

Based on CLE analysis of IBS patients with a suspected food intolerance, exposure to candidate food antigens caused immediate breaks, increased intervillous spaces, and increased IELs in the intestinal mucosa. These changes are associated with patient responses to exclusion diets. Registered at clinicaltrials.gov (registration number: NCT01692613).

The role of FODMAPs in irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a condition affecting approximately 10-15% of Western populations. The Rome III criteria are applied to many studies to validate the diagnosis of IBS. The low fermentable oligo, di, monosaccharides and polyol (FODMAP) diet has been the subject of many robust clinical trials and is now used as the primary dietary therapy internationally. This review examines the current evidence for the role of the low FODMAP diet in IBS.

RECENT FINDINGS

Detailed commentary on original research involving FODMAPs and IBS symptoms from 2013 to 2014 is provided.

SUMMARY

The low FODMAP diet has been shown to be an efficacious therapy for reduction of functional gastrointestinal symptoms seen in IBS. Recent publications provide randomized controlled trial and prospective observational evidence in support of the diet for symptom management. The low FODMAP diet appears to be superior to a gluten-free diet in people with self-reported nonceliac gluten sensitivity. Although the low FODMAP diet has not been shown to reduce the prebiotic effect in the colon, total colonic bacterial load was reduced. Further research investigating the potential health implications of both this and the nutritional adequacy of the liberalized low FODMAP diet is required.