Therapeutic Effects of a Low FODMAP Diet on Symptoms, Gut Microbiota, and Anxiety in Patients with Irritable Bowel Syndrome

of these studies were performed in Western countries; therefore, as the generalizability of these results may be limited, studies investigating the effectiveness of the low FODMAP diet in non-Western populations are required.

Covering the Cover

World Gastroenterology Organisation Global Guidelines: Diet and the Gut.

Irritable bowel syndrome (IBS) and chronic idiopathic constipation ((CIC) also referred to as functional constipation) are two of the most common functional gastrointestinal disorders worldwide. IBS is a global problem, with anywhere from 5 to 15% of the general population experiencing symptoms that would satisfy a definition of IBS (1,2). In a systematic review on the global prevalence of IBS, Lovell and Ford (1) documented a pooled prevalence of 11% with all regions of the world suffering from this disorder at similar rates. Given its prevalence, the frequency of symptoms, and their associated debility for many patients and the fact that IBS typically occurs in younger adulthood, an important period for furthering education, embarking on careers, and/or raising families, the socioeconomic impact of IBS is considerable. These indirect medical costs are frequently compounded by the direct medical costs related to additional medical tests and the use of various medical and nonmedical remedies that may have limited impact. CIC is equally common; in another systematic review, Suares and Ford (3) reported a pooled prevalence of 14%, and also noted that constipation was more common in females, in older subjects, and those of lower socioeconomic status (3). Chronic constipation has also been linked to impaired quality of life (4), most notably among the elderly (5). Neither IBS nor CIC are associated with abnormal radiologic or endoscopic abnormalities, nor are they associated with a reliable biomarker; diagnosis currently rests entirely, therefore, on clinical grounds. Although a number of clinical definitions of both IBS and CIC have been proposed, the criteria developed through the Rome process, currently in its third iteration, have been those most widely employed in clinical trials and, therefore, most relevant to any review of the literature on the management of these disorders. According to Rome III, IBS is defined on the basis of the presence of: Recurrent abdominal pain or discomfort at least 3 days/month in the past 3 months associated with two or more of the following: Improvement with defecation Onset associated with a change in frequency of stool Onset associated with a change in form (appearance) of stool These criteria should be fulfilled for the past 3 months with symptom onset at least 6 months before diagnosis (6). Rome III defines functional constipation as: the presence of two or more of the following: Straining during at least 25% of defecations Lumpy or hard stools in at least 25% of defecations Sensation of incomplete evacuation for at least 25% of defecations Sensation of anorectal obstruction/blockage for at least 25% of defecations Manual maneuvers to facilitate at least 25% of defecations (e.g., digital evacuation, support of the pelvic floor) Fewer than three defecations per week Furthermore, loose stools are rarely present without the use of laxatives and there are insufficient criteria for IBS. Again, these criteria should be fulfilled for the past 3 months with symptom onset at least 6 months before diagnosis (6). In Rome III, IBS is subtyped according to predominant bowel habit as IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed type (IBS-M), and unclassified (IBS-U). The definition of bowel habit type is, in turn, based on the patient's description of stool form by referring to the Bristol Stool Scale (7). The recognition that IBS sufferers segregate into subtypes according to predominant bowel habit, together with research findings suggesting that IBS-C and IBS-D may be pathophysiologically distinct entities (8,9,10), led to the development of therapies specifically directed at each of these subtypes. Nonetheless, it is worth noting that symptoms may not be stable over a lifetime and individuals may exhibit one IBS subtype during a period, and then a different IBS subtype during another period in their lives. However, although there is general awareness of the Rome criteria, they are infrequently employed in the assessment of IBS and CIC in clinical practice (11). To provide more "clinician friendly" definitions, as well as to permit inclusion of studies that predated the Rome process, American College of Gastroenterology Task Forces suggested the following definitions in prior systematic reviews: IBS is defined by: abdominal discomfort associated with altered bowel habits (12). Constipation is defined as: a symptom-based disorder defined as unsatisfactory defecation and is characterized by infrequent stools, difficult stool passage, or both. Difficult stool passage includes straining, a sense of difficulty passing stool, incomplete evacuation, hard/lumpy stools, prolonged time to stool, or need for manual maneuvers to pass stool. CIC is defined as the presence of these symptoms for at least 3 months (13). It is important to note that the Rome III criteria state that individuals with chronic constipation do not fulfill criteria for IBS, with pain or discomfort being a major determinant in the latter. In practice, a clear separation between CIC and IBS with constipation may be challenging and studies have shown, not only considerable overlap between these entities (14,15,16), but also a significant tendency for patients to migrate between these diagnoses over time (15). It is appropriate therefore that in this update of prior American College of Gastroenterology monographs on IBS and CIC, these entities be addressed in the same exercise (12,13,17). The goal of this exercise, therefore, was to update the most recent systematic reviews commissioned by the American College of Gastroenterology on IBS from 2009 (17) and CIC from 2005 (13). METHODS We have conducted a series of systematic reviews on the efficacy of therapy in IBS and CIC. There have been several systematic reviews of therapy for IBS and CIC published in the past 5 years (18,19,20,21,22). There have been considerable data published in the intervening time, and hence we have, therefore, updated all these systematic reviews of IBS and CIC and synthesized the data, including the information from new trials, where appropriate. The primary objective of this exercise was to assess the efficacy of available therapies in treating IBS and CIC compared with placebo or no treatment. The secondary objectives included assessing the efficacy of available therapies in treating IBS according to predominant stool pattern reported (IBS with constipation, IBS with diarrhea, and mixed IBS), as well as assessing adverse events with therapies for both IBS and CIC. Systematic review methodology We evaluated manuscripts that studied adults (aged >16 years) using any definition of IBS or CIC. For IBS, this included a clinician-defined diagnosis, the Manning criteria (23), the Kruis score (24), or Rome I (25), II (26), or III (6) criteria. For CIC, this included symptoms diagnosed by any of the Rome criteria (6,25,26), as well as a clinician-defined diagnosis. We included only parallel-group randomized controlled trials (RCTs) comparing active intervention with either placebo or no therapy. Crossover trials were eligible for inclusion, provided extractable data were provided at the end of the first treatment period, before crossover. For IBS, the following treatments were considered: Diet and dietary manipulation Fiber Interventions that modify the microbiota: probiotics, prebiotics, antibiotics Antispasmodics Peppermint oil Loperamide Antidepressants Psychological therapies, including hypnotherapy Serotonergic agents Prosecretory agents Polyethylene glycol For CIC, the following were considered: Fiber Osmotic and stimulant laxatives 5-HT4 agonists Prosecretory agents Biofeedback Bile acid transporter inhibitors Probiotics Subjects needed to be followed up for at least 1 week. To be eligible, trials needed to include one or more of the following outcome measures: Global assessment of improvement in IBS or CIC symptoms Improvement in abdominal pain for IBS Global IBS symptom or abdominal pain scores for IBS Mean number of stools per week during therapy for CIC Search strategy for identification of studies MEDLINE (1946 to October 2013), EMBASE and EMBASE Classic (1947 to October 2013), and the Cochrane central register of controlled trials were searched. Studies on IBS were identified with the terms irritable bowel syndrome and functional diseases, colon (both as medical subject headings (MeSH) and free text terms), and IBS, spastic colon, irritable colon, and functional adj5 bowel (as free text terms). For RCTs of dietary manipulation, these were combined using the set operator AND with studies identified with the terms: diet, fat-restricted, diet, protein-restricted, diet, carbohydrate-restricted, diet, gluten-free, diet, macrobiotic, diet, vegetarian, diet, Mediterranean, diet fads, gluten, fructose, lactose intolerance, or lactose (both as MeSH and free text terms), or the following free text terms: FODMAP$, glutens, food adj5 intolerance, food allergy, or food hypersensitivity. For RCTs of fiber, antispasmodics, and peppermint oil, these were combined using the set operator AND with studies identified with the terms: dietary fiber, cereals, psyllium, methylcellulose, sterculia, karaya gum, parasympatholytics, hyoscyamine, scopolamine, trimebutine, muscarinic antagonists, or butylscopolammonium bromide (both as MeSH and free text terms), or the following free text terms: bulking agent, psyllium fiber, fiber, husk, bran, ispaghula, wheat bran, calcium polycarbophil, spasmolytics, spasmolytic agents, antispasmodics, mebeverine, alverine, pinaverium bromide, otilonium bromide, cimetropium bromide, hyoscine butyl bromide, butylscopolamine, peppermint oil, or colpermin. For RCTs of probiotics, these were combined using the set operator AND with studies identified with the terms: Saccharomyces, Lactobacillus, Bifidobacterium, Escherichia coli, or probiotics (both as MeSH and free text terms). For RCTs of prebiotics and synbiotics, these were combined using the set operator AND with studies identified with the term: prebiotic (both MeSH and free text terms) or synbiotic (both MeSH and free text terms). For RCTs of antibiotics, these were combined using the set operator AND with studies identified with the terms: anti-bacterial agents, penicillins, cephalosporins, rifamycins, quinolones, nitroimidazoles, tetracycline, doxycycline, amoxicillin, ciprofloxacin, metronidazole, or tinidazole (both as MeSH and free text terms), or the following free text terms: antibiotic or rifamixin. For RCTs of loperamide, these were combined using the set operator AND with studies identified with the terms: loperamide or antidiarrheals (both as MeSH and free text terms), or the following free text terms: imodium or lopex. For RCTs of antidepressants and psychological therapies, including hypnotherapy, these were combined using the set operator AND with studies identified with the terms: psychotropic drugs, antidepressive agents, antidepressive agents (tricyclic), desipramine, imipramine, trimipramine, doxepin, dothiepin, nortriptyline, amitriptyline, selective serotonin reuptake inhibitors, paroxetine, sertraline, fluoxetine, citalopram, venlafaxine, cognitive therapy, psychotherapy, behavior therapy, relaxation techniques, or hypnosis (both as MeSH and free text terms), or the following free text terms: behavioral therapy, relaxation therapy, or hypnotherapy. For RCTs of serotonergic agents, these were combined using the set operator AND with studies identified with the terms: serotonin antagonists, serotonin agonists, cisapride, receptors (serotonin, 5-HT3), or receptors (serotonin, 5-HT4) (both as MeSH and free text terms), or the following free text terms: 5-HT3, 5-HT4, alosetron, cilansetron, ramosetron, prucalopride, mosapride, or renzapride. For RCTs of pro-secretory agents, these were combined using the set operator AND with studies identified with the following free text terms: linaclotide or lubiprostone. For RCTs of polyethylene glycol (PEG), these were combined using the set operator AND with studies identified with the term polyethylene glycol (both as a MeSH and free text term). Studies on CIC were identified with the terms constipation or gastrointestinal transit (both as MeSH and free text terms), or functional constipation, idiopathic constipation, chronic constipation, or slow transit (as free text terms). For the search involving biofeedback, the free text terms dyssynergia, pelvic floor dysfunction, anismus, and outlet obstruction were also added. For RCTs of fiber, these were combined using the set operator AND with studies identified with the terms: dietary fiber, cellulose, plant extracts, psyllium, cereals, plantago, or methylcellulose (both as MeSH and free text terms), or the following free text terms: fiber, soluble fiber, insoluble fiber, bran, ispaghula, metamucil, fybogel, or ispaghula. For RCTs of osmotic and stimulant laxatives, these were combined using the set operator AND with studies identified with the terms: laxatives, cathartics, anthraquinones, phenolphthaleins, indoles, phenols, lactulose, polyethylene glycol, senna plant, senna extract, bisacodyl, phosphates, dioctyl sulfosuccinic acid, magnesium, magnesium hydroxide, sorbitol, poloxamer (both as MeSH and free text terms), or the following free text terms: sodium picosulphate, docusate, milk of magnesia, danthron, senna, and poloxalkol. For RCTs of 5-HT4 agonists, these were combined using the set operator AND with studies identified with the terms: serotonin agonists, receptors, or serotonin, 5-HT4 (both as MeSH and free text terms), or the following free text terms: prucalopride, velusetrag, or naronapride. For RCTs of pro-secretory agents, these were combined using the set operator AND with studies identified with the following free text terms: lubiprostone or linaclotide. For RCTs of biofeedback, these were combined using the set operator AND with studies identified with the MESH terms biofeedback and psychology and the following free text terms: biofeedback or neuromuscular training. For RCTs of bile acid transporter inhibitors, these were combined using the set operator AND with studies identified with the following free text terms: bile acid transporter, elobixibat, or A3309. For RCTs of probiotics, these were combined using the set operator AND with studies identified with the terms: Saccharomyces, Lactobacillus, Bifidobacterium, E. coli, or probiotics (both as MeSH and free text terms). For RCTs of prebiotics and synbiotics, these were combined using the set operator AND with studies identified with the term: prebiotic (both MESH and free text terms) or synbiotic (both MESH and free text terms). The search was limited to humans. No restrictions were applied with regard to language of publication. A recursive search of the bibliography of relevant articles was also conducted. DDW (Digestive Diseases Week) and UEGW (United European Gastroenterology Week) abstract books were hand searched between 2000 and 2013. Authors of trial reports that did not give enough detail for adequate data extraction were contacted and asked to contribute full data sets. Experts in the field were contacted for leads on unpublished studies. Trials were assessed for risk of bias according to the methods described in the Cochrane handbook [27] using the following characteristics: method used to generate the randomization schedule, method used to conceal treatment allocation, implementation of masking, completeness of follow-up, and conduct of an intention-to-treat analysis. Eligibility, quality, and outcome data were extracted by the lead reviewer (Alexander Ford) and by a masked second reviewer (Paul Moayyedi) on to specially developed forms. Any discrepancy was resolved by discussion between the two reviewers in order to reach a consensus. Data were extracted as intention-to-treat analyses, where all dropouts were assumed to be treatment failures, wherever trial reporting allowed this. Data synthesis For IBS, whenever possible, any improvement of global IBS symptoms as a binary outcome was taken as the primary outcome measure. If this was not available, improvement in abdominal pain was used. For CIC, any improvement of global CIC symptoms as a binary outcome was taken as the primary outcome measure. The impact of interventions was expressed as a relative risk (RR) of IBS or CIC symptoms not improving, together with 95% confidence intervals (CIs). If there were sufficient data, RRs were combined using the DerSimonian and Laird random effects model (28) to give a more conservative estimate of the efficacy of individual IBS therapies. For continuous data, such as global IBS symptom scores or individual IBS symptom scores, a standardized mean difference, with 95% CIs, was calculated. It should be noted that some treatments may be beneficial in IBS or CIC because of the effects on outcomes other than global symptoms or abdominal pain, but this was not evaluated and was outside of the scope of this review. Tests of heterogeneity were reported (29). When the test of heterogeneity was significant (P<0.10 and/or I2>25%), the reasons for this were explored by evaluating differences in study population, study design, or study end points in subgroup analyses. Publication bias or other causes of small study effects were evaluated using tests for funnel plot asymmetry (30), where sufficient studies were identified (31). The number needed to treat (NNT), which is the number of patients who would need to receive active therapy, over and above the control therapy, for one to experience an improvement in symptoms, and the number needed to harm (NNH), which is the number of patients who would need to receive active therapy, over and above the control therapy, for one to experience an adverse event were calculated as the inverse of the risk difference from the meta-analysis and checked using the formula: NNT = 100 / RRR × BR, where BR is baseline risk and RRR is relative risk reduction. Methodology for assessing levels of evidence and grading recommendations We used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system for grading the quality of evidence and strength of recommendation for each medical intervention (32). The system has been widely used in evidence-based guidelines and is endorsed by all major gastrointestinal societies (http://www.gradeworkinggroup.org). The quality of the evidence is based on the study design, as well as the extent of risk of bias, inconsistency, indirectness, imprecision, and publication bias that exists for the evidence supporting the intervention (33). Quality of evidence is described as high to very low, depending on the extent to which further evidence would change the estimate of treatment effect (Box 1). The grading scheme also classifies recommendations as strong or weak, according to the quality of the evidence, applicability to all patient groups, balance of benefits and risks, patient preferences, and cost. With this graded recommendation, the clinician receives guidance about whether or not recommendations should be applied to most patients, and whether or not recommendations are likely to change in the future after production of new evidence. "Strong" recommendations represent a "recommendation that can apply to most patients in most circumstances and further evidence is unlikely to change our confidence in the estimate of treatment effect." The summary of the evidence for IBS is presented in Table 1, the reasons for the decision on the quality of that evidence in Table 2, and the reasons for the strength of recommendation in Table 3. Similarly, the summary of the evidence for CIC is presented in Table 4, the reasons for the decision on quality of the evidence in Table 5, and the reasons for the strength of recommendation in Table 6.Box 1.: Interpretation of the grading of the quality of evidenceTable 1: Summary of results of monograph on interventions for IBSTable 2: Reasons for quality of evidence of assessment for IBS data according to GRADE criteriaTable 2: Continued.Table 3: Reasons for strength of recommendation for IBS therapies according to GRADE criteriaTable 4: Summary of results of monograph on interventions for CICTable 5: Reasons for quality of evidence of assessment of data on CIC according to GRADE criteriaTable 6: Reasons for strength of recommendation for treatments of CIC according to GRADE criteriaRESULTS Irritable bowel syndrome 1. Diet and dietary manipulation in IBS (a) Role of diet in IBS: Although food intake is one of the most common precipitants of symptoms in IBS (34), responses to food and with of the diet have not typically in the of a on their IBS sufferers have their to this or guidance from dietary IBS patients that they have an to although food are in IBS although the prevalence of food in societies is between 1 and in of gastrointestinal patients that that their symptoms food or food IBS symptoms to represent food intolerance, although only of patients can the food in a on their with and a of objective evidence to a studies have that a of IBS patients dietary to an extent that may their Role of dietary manipulation in may symptoms in individual IBS Quality of very We identified RCTs that evaluated dietary intervention in IBS to data of relevant symptom data and an intervention week three RCTs involving patients The first of these addressed the impact of in IBS. In a patients with IBS were randomized to either on a diet or to receive of on of an In the reported that their symptoms were not controlled as compared with in the placebo symptom scores for abdominal pain, with stool and were in those who a The second of these studies the of food or as not by but by In a parallel-group IBS patients were randomized to either an diet based on the presence of to various or a were followed for and symptoms assessed using a global impact score and the IBS with in the diet in the diet intervention noted a significant improvement in The reported in those with high to their The third study the of and IBS patients were randomized to a diet or their diet for those randomized to the diet, reported adequate control of their symptoms compared with of the diet Stool did not between stool frequency was in the diet A significant of this study was the of the dietary the of dietary in the of symptoms, or in the of IBS, is being To two and have been addressed in clinical trials, although it is that other (e.g., of and with the may also be relevant to the effects of food or food the that any of the of an diet or of a food in IBS the data provide limited guidance on the of diet in the management of IBS. and but their in the management of IBS need to be Fiber in IBS Fiber symptom in IBS. Quality of but not bran, symptom in IBS. Quality of intake of dietary is frequently to bowel for IBS, for However, insoluble frequently and abdominal In our prior systematic review we identified two additional studies for a of RCTs involving but trials did not IBS by subtype and only two to IBS-C In the study to patients, of were IBS-C and were were randomized to one of three of the soluble psyllium, of the insoluble bran, or of a placebo for the first a of patients psyllium, but not bran, reported adequate symptom for at least compared with placebo psyllium 95% was more than placebo during the third of treatment only 3 months of symptom in the psyllium was by points compared with points in the placebo and points in the No differences were with to quality of was most common in the most because of in IBS. Data on adverse events were only provided by trials These trials evaluated patients, but as of adverse events were small in 5 of the trials, of data was not A of of patients reported adverse events compared with of in the placebo Although its use in the management of IBS is time the status of fiber, in in IBS, is from may symptoms and provide soluble and psyllium, in provide in IBS. These effects to benefits in terms of of 3. Interventions that modify the microbiota: probiotics, prebiotics, and antibiotics The that the be relevant to IBS first from the that a although of individuals who an of on to IBS IBS Although has been linked to and and in the have been described in IBS, the of the to or other symptoms in IBS, is although both small and and in the have also been linked to IBS the of to IBS and findings in to the in patient probiotics, and have been used for on an basis by IBS they have only been to in clinical The of studies in IBS challenging as studies have employed different and in various patient and in Although the suggested that more than of all IBS sufferers studies have, in to such a high prevalence of in IBS These results may to to the test that may provide an of the this provided a for assessing antibiotics in IBS. a has efficacy in clinical trials in and although significant were over placebo in global IBS symptoms as well as in it is important to note that tests for were not in these trials, the of of in IBS (a) and in IBS: There is insufficient evidence to prebiotics or in IBS. Quality of very Probiotics in as a probiotics global symptoms, and in IBS.

BackgroundThe long-term management of irritable bowel syndrome (IBS) poses many challenges. In short-term studies, eHealth interventions have been demonstrated to be safe and practical for at-home monitoring of the effects of probiotic treatments and a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). IBS has been linked to alterations in the microbiota.ObjectiveThe aim of this study was to determine whether a web-based low-FODMAP diet (LFD) intervention and probiotic treatment were equally good at reducing IBS symptoms, and whether the response to treatments could be explained by patients’ microbiota.MethodsAdult IBS patients were enrolled in an open-label, randomized crossover trial (for nonresponders) with 1 year of follow-up using the web application IBS Constant Care (IBS CC). Patients were recruited from the outpatient clinic at the Department of Gastroenterology, North Zealand University Hospital, Denmark. Patients received either VSL#3 for 4 weeks (2 × 450 billion colony-forming units per day) or were placed on an LFD for 4 weeks. Patients responding to the LFD were reintroduced to foods high in FODMAPs, and probiotic responders received treatments whenever they experienced a flare-up of symptoms. Treatment response and symptom flare-ups were defined as a reduction or increase, respectively, of at least 50 points on the IBS Severity Scoring System (IBS-SSS). Web-based ward rounds were performed daily by the study investigator. Fecal microbiota were analyzed by shotgun metagenomic sequencing (at least 10 million 2 × 100 bp paired-end sequencing reads per sample).ResultsA total of 34 IBS patients without comorbidities and 6 healthy controls were enrolled in the study. Taken from participating subjects, 180 fecal samples were analyzed for their microbiota composition. Out of 21 IBS patients, 12 (57%) responded to the LFD and 8 (38%) completed the reintroduction of FODMAPs. Out of 21 patients, 13 (62%) responded to their first treatment of VSL#3 and 7 (33%) responded to multiple VSL#3 treatments. A median of 3 (IQR 2.25-3.75) probiotic treatments were needed for sustained symptom control. LFD responders were reintroduced to a median of 14.50 (IQR 7.25-21.75) high-FODMAP items. No significant difference in the median reduction of IBS-SSS for LFD versus probiotic responders was observed, where for LFD it was –126.50 (IQR –196.75 to –76.75) and for VSL#3 it was –130.00 (IQR –211.00 to –70.50; P>.99). Responses to either of the two treatments were not able to be predicted using patients’ microbiota.ConclusionsThe web-based LFD intervention and probiotic treatment were equally efficacious in managing IBS symptoms. The response to treatments could not be explained by the composition of the microbiota. The IBS CC web application was shown to be practical, safe, and useful for clinical decision making in the long-term management of IBS. Although this study was underpowered, findings from this study warrant further research in a larger sample of patients with IBS to confirm these long-term outcomes.Trial RegistrationClinicalTrials.gov NCT03586622; https://clinicaltrials.gov/ct2/show/NCT03586622

Immune Activation in Patients With Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) stands as a prevalent functional gastrointestinal condition known for causing persistent abdominal pain, changes in bowel patterns, and diminished quality of life. The low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet has emerged as a potential approach to managing IBS through dietary adjustments. To explore how the low FODMAP diet affects symptom relief, nutritional well-being, and overall quality of life in IBS patients when compared to those adhering to a standard diet. A retrospective cohort study was conducted, including patients with IBS categorized into a regular diet group and a low FODMAP diet group. Dietary intake, daily nutrient intake, IBS symptom severity, adverse events, and quality of life were assessed. The low FODMAP diet group demonstrated significantly lower intake of fermentable carbohydrates, including total dietary fiber, fructose, lactose, sorbitol, and total carbohydrates, compared to the regular diet group. Additionally, the low FODMAP diet group exhibited favourable nutritional profiles, reflecting higher intake and utilization of essential nutrients such as vitamin C, iron, calcium, vitamin D, and omega-3 fatty acids. Moreover, significant improvements in symptom severity, adverse event profiles, and quality-of-life scores were observed in the low FODMAP diet group compared to the regular diet group. The Low-FODMAP Diet significantly alters nutrient intake in IBS patients, which may contribute to the observed symptom relief.

A low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet is frequently applied to patients with irritable bowel syndrome (IBS) as a treatment to reduce functional gastrointestinal symptoms, with evidence of its efficacy mounting worldwide.1, 2 The success of the dietary therapy is now frequently applied to patients with inflammatory bowel disease (IBD) and co-existing functional symptoms. Evidence for application of a low FODMAP diet in the IBD population is limited to a retrospective study of patients with quiescent IBD and IBS-like symptoms, in which more than 50% of patients had a reduction of symptoms.3 While beneficial for symptom reduction, there is evidence suggesting that a low FODMAP diet also has negative effects on microbiota. This was first suggested in a trial where a dietitian-taught low FODMAP diet reduced relative abundance of fecal Bifidobacteria spp. in IBS subjects compared with parallel cohort of IBS subjects on their habitual diet.4 A more closely controlled trial that compared fecal bacteria of IBS and healthy subjects after being provided two diets that varied only in FODMAP content showed that a low FODMAP diet was associated with reduction of total fecal bacterial load and specific reduction of the highly butyrate-producing Clostridium cluster XIVa and Akkermansia muciniphila, a likely favorable bacteria that promotes short-chain fatty acid production and an increase in the mucus-degrading Ruminococcus torques.5 The application of a low FODMAP diet may raise concerns in the IBS population if applied long term; however, risk to an IBD population may be more significant. Literature suggests that the changes in fecal bacterial seen from a reduced FODMAP intake seem to mimic those seen in patients with Crohn's disease. Patients with Crohn's disease are more likely to have reduced butyrate-producing bacteria, Bifidobacteria spp. and A. muciniphila and increase R. torques and Ruminococcus gnavus.6-8 One bacterium of specific interest in a Crohn's Disease population is the butyrate-producing Faecalibacterium prausnitzii, as mucosal F. prausnitzii has predicted onset of active disease.9 Similarly, in vitro and animal models suggest that A. muciniphila may also predict Crohn's disease activity.8, 10 A low FODMAP diet may further impact negatively on microbiota of patients with Crohn's disease, a population already at risk of dysbiosis. With data indicating that caution should be taken in applying a low FODMAP diet, two different approaches may be used in applying an FODMAP restriction for treatment of functional gut symptoms; the 'top-down' or the 'bottom-up' approach. The more traditional top-down approach involves the patient restricting all or most foods considered to contain FODMAPs for a four-week to eight-week period. Then, if symptom benefit is seen, dietary liberalization is guided through using set food and dose challenges or general recommendations describing FODMAP dosing across restricted foods. This top-down approach is best suited to patients where the success of a low FODMAP diet or the type or amount of FODMAP tolerance is uncertain; in patients who do not normally eat a lot of FODMAPs or who are very symptomatic; or in patients who would prefer this approach. Conversely, the bottom-up approach involves reducing specific FODMAPs or a few foods that are very high in FODMAPs for a time period then further restriction of foods if necessary. Arguably, this bottom-up approach should be applied in all patients who are at risk of dysbiosis, including patients with IBD. Other indications for this more gentle restriction include patients at risk of nutritional inadequacy or who have other dietary restrictions, which may again encompass the IBD population. Because of the complex and individual nature of an FODMAP restriction, implementation should be done in guidance with a dietitian well versed in IBD, IBS, and dietary FODMAPs. In addition to appropriate FODMAP manipulation, a dietitian will assess and closely monitor nutritional adequacy with dietary restriction and manage as appropriate, including patients in whom nutrient absorption is impaired or dietary intake is altered.

The low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet is an effective dietitian-led treatment for irritable bowel syndrome (IBS). An increasing demand of IBS patient referrals has warranted group FODMAP education led by specialist dietitians. Psychological co-morbidities are common in IBS, although how the low FODMAP diet influences psychological outcomes is not understood. The present study aimed to evaluate symptom related outcomes of the diet following group education and assess its effect on psychological profiles. An observational, prospective study was conducted in 55 IBS patients who attended FODMAP Restriction and FODMAP Reintroduction group sessions. Data were collected at baseline and follow-up after FODMAP Restriction and analysed using descriptive and McNemar's tests. Primary outcome was evaluated by IBS Symptom Severity Score (IBS-SSS). Secondary psychological outcomes included anxiety and depression using the Hospital Anxiety and Depression Scale (HADS) and risk of eating disorder questionnaire (SCOFF). After FODMAP Restriction, 27 of 55 (54%) patients reported clinically relevant symptom improvement, as defined by a reduction in the IBS-SSS ≥50points, whereas no differences were recorded in the proportion of patients identified with clinical anxiety (p = 1.000) or clinical depression (p = 0.375). Positively, no increased risk of an eating disorder was observed. The present study provides data supporting the efficacy of the low FODMAP diet in IBS patients who attended dietitian led group education settings in tertiary care. Clinically significant improvements in gastrointestinal symptoms were observed, although with no impact on clinical levels of anxiety, depression or the risk of an eating disorder.

Background:Aloe barbadensis Mill. (Aloe) extract was found to be well-tolerated, safe and showed beneficial effects in subsets of irritable bowel syndrome (IBS) patients in two randomized, double-blind, controlled studies. However, the individual studies were underpowered to perform subgroup analyses. We therefore determined the effect of Aloe extract in IBS subgroups in a post hoc analysis combining the results from the two studies.Methods:Data from the two controlled studies comparing Aloe and control treatment taken orally for 4 weeks, were pooled. Both studies included IBS patients fulfilling the ROME III criteria and IBS Symptom Severity Score (IBS-SSS) was assessed. We analysed the effect of Aloe extract on IBS symptom severity and the proportion of responders (IBS-SSS reduction ⩾ 50) in IBS subgroups.Results:In total, 213 IBS patients were included in the post hoc subgroup analyses. A reduction in overall symptom severity, primarily driven by effect on pain severity and frequency, comparing baseline versus end of treatment, was recorded in IBS patients with diarrhoea (IBS-D) receiving Aloe (n = 38, p < 0.001) but not control treatment (n = 33, p = 0.33), with difference between the treatment groups (p = 0.01). Moreover, the frequency of responders was higher in IBS-D patients receiving Aloe (n = 22, 58%) compared to control treatment (n = 10, 30%) (p = 0.02). The effect of Aloe extract treatment on IBS symptom severity was not superior to control treatment in the other IBS subtypes.Conclusion:Aloe extract improves symptom severity in IBS-D patients and can be regarded as a safe and effective treatment option for this patient group.

A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome

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Objective To improve the ability of early recognition of psychological disorders in irritable bowel syndrome (IBS) patients by analyzing somatic and digestive tract symptoms of IBS patients complicated with depression. Methods From May to October 2014, 102 out-patients with IBS were enrolled who completed the questionnaire and were followed-up. Another 102 gender and age matched individual who received check-up were set as healthy controls. The detailed clinical data of all IBS patients were collected. The scores of Hamilton depression scale (HAMD), digestive symptom questionnaire, somatic symptom questionnaire and irritable bowel syndrome symptom severity score (IBS-SSS) were evaluated in the IBS patients, and HAMD was evaluated in healthy controls. The t test or chi-square test was performed for statistical analysis. Results HAMD score of the IBS group was 19.1±17.0, which was higher than that of control group (3.2±2.9; t=8.966, P<0.05). Among the 102 IBS patients, 58 were complicated with depression (56.9%) and 44 (43.1%) without depression. Among the IBS patients complicated with depression, 75.9% (44/58) were overlapped with gastrointestinal symptoms, which was higher than that of patients without depression (34.1%, 15/44), and the difference was statistically significant (χ2=17.902, P<0.01). The typical somatic symptoms of IBS patients complicated with depression were headaches, dizziness, insomnia, palpitations, chest pain, and chest tightness.The results of IBS-SSS indicated that scores of duration of abdominal pain, bloating degree and the impacts on quality of life in IBS patients complicated with depression were 78.1±28.7, 53.7±17.9 and 69.4±19.7, which were significantly higher than those of IBS patients without depression (34.7±16.6, 37.7±12.5 and 32.4±12.7). The score of defecation satisfaction of IBS patients complicated with depression was 43.7±16.4, which was lower than that of patients without depression (55.0±20.3), and all the differences were statistically significant (t=-8.930, -2.326, -8.913 and -2.344, all P<0.05). Conclusions The somatic and overlapped digestive symptoms of IBS patients complicated with depression are obvious and complicated. For IBS patients with obvious extra symptoms, mental disorders should be taken into consideration. On the basis of the treatment of IBS symptoms, the treatment of psychological disorders are also needed. Key words: Irritable bowel syndrome; Depression; Somatic syndrome

Dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) is effective in the management of functional gastrointestinal symptoms that occur in irritable bowel syndrome (IBS). Numerous reviews have been published regarding the evidence for their restriction in the low FODMAP diet; however, few reviews discuss the implementation of the low FODMAP diet in practice. The aim of this review is to provide practical guidance on patient assessment and the implementation and monitoring of the low FODMAP diet. Broadly speaking, the low FODMAP diet consists of three stages: FODMAP restriction; FODMAP reintroduction; and FODMAP personalisation. These stages can be covered in at least two dietetic appointments. The first appointment focuses on confirmation of diagnosis, comprehensive symptom and dietary assessment, detailed description of FODMAPs and their association with symptom induction, followed by counselling regarding FODMAP restriction. Dietary counselling should be tailored to individual needs and appropriate resources provided. At the second appointment, symptoms and diet are re-assessed and, if restriction has successfully reduced IBS symptoms, education is provided on FODMAP reintroduction to identify foods triggering symptoms. Following this, the patient can follow FODMAP personalisation for which a less restrictive diet is consumed that excludes their personal FODMAP triggers and enables a more diverse dietary intake. This review provides evidence and practice guidance to assist in delivering high-quality clinical service in relation to the low FODMAP diet.

Effectiveness Of Probiotics In Irritable Bowel Syndrome: A Systematic Review With Meta-Analysis.