The low FODMAP diet in clinical practice: where are we and what are the long-term considerations?

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) improves functional bowel symptoms and is a second-line dietary management strategy for the treatment of irritable bowel syndrome (IBS). The diet is complex and involves three stages: restriction, reintroduction and personalisation and clinical effectiveness is achieved with dietitian-led education; however, this is not always available. The aim of this review is to provide an update on the evidence for using the low FODMAP diet, with a focus on the impact of FODMAP restriction and reintroduction considering long-term management of IBS in a clinical setting. Randomised controlled trials have assessed symptom response, quality of life, dietary intake and changes to the gut microbiota during FODMAP restriction. Systematic reviews and meta-analyses consistently report that FODMAP restriction has a better symptom response compared with control diets and a network analysis reports the low FODMAP diet is superior to other dietary treatments for IBS. Research focused on FODMAP reintroduction and personalisation is limited and of lower quality, however common dietary triggers include wheat, onion, garlic, pulses and milk. Dietitian-led delivery of the low FODMAP diet is not always available and alternative education delivery methods, e.g. webinars, apps and leaflets, are available but remove the personalised approach and may be less acceptable to patients and may introduce safety concerns in terms of nutritional adequacy. Predicting response to the low FODMAP diet using symptom severity or a biomarker is of great interest. More evidence on less restrictive approaches and non-dietitian-led education delivery methods are needed.

Optimizing educational methods for the low FODMAP diet in disorders of gut-brain interaction: A feasibility randomized controlled trial.

BACKGROUND: A diet low in fermentable oligo-saccharides, di-saccharides, mono-saccharides and polyols (low FODMAP diet) is complex and clinical effectiveness is achieved with dietitian-led education, although dietitian availability in clinical practice varies. This study aimed to assess the feasibility of undertaking a trial to investigate the clinical and cost-effectiveness of different education delivery methods of the low FODMAP diet in patients with disorders of gut-brain interaction (DGBI). METHODS: In this feasibility randomized controlled trial, patients with DGBI requiring the low FODMAP diet were randomized to receive one of the following education delivery methods: booklet, app, or dietitian. Recruitment and retention rates, acceptability, symptoms, stool output, quality of life, and dietary intake were assessed. KEY RESULTS: Fifty-one patients were randomized with a recruitment rate of 2.4 patients/month and retention of 48 of 51 (94%). Nobody in the booklet group strongly agreed that this education delivery method enabled them to self-manage symptoms without further support, compared to 7 of 14 (50%) in the dietitian group (p = 0.013). More patients reported adequate relief of symptoms in the dietitian group (12, 80%) compared with the booklet group (7, 39%; p = 0.026), but not when compared to the app group (10, 63%, p > 0.05). There was a greater decrease in the IBS-SSS score in the dietitian group (mean -153, SD 90) compared with the booklet group (mean -90, SD 56; p = 0.043), but not when compared with the app group (mean -120, SD 62; p = 0.595). CONCLUSIONS & INFERENCES: Booklets were the least acceptable education delivery methods. Dietitian-led consultations led to high levels of clinical effectiveness, followed by the app, while the dietitian was superior to booklets alone. However, an adequately powered clinical trial is needed to confirm clinical effectiveness of these education delivery methods.

Development and validation of a knowledge, attitudes and practices questionnaire in the dietary management of irritable bowel syndrome.

OBJECTIVE: To develop and validate a questionnaire assessing knowledge, attitudes and practices in the dietary management of IBS. SUBJECTS/METHODS: An initial pool of 151 questions was generated addressing three domains (knowledge, attitudes, practices). Academic/senior clinical dietitians (n = 5) provided written feedback and a focus group (n = 4 gastroenterology dietitians) was undertaken to evaluate content and face validity of the question-items. Items considered irrelevant were removed and the refined questionnaire was administered to dietitians with different levels of IBS experience (n = 154) for further psychometric testing. Item reduction analysis was assessed by item difficulty index, discrimination index and point-biserial correlation. Construct validity was assessed via principal component analysis (PCA) and the 'known-groups' method. Internal reliability was assessed by Kuder-Richarson Formula 20 and Cronbach's alpha coefficient and external reliability by interclass correlation coefficient among participants who completed the instrument at baseline and two weeks later (n = 28). RESULTS: Face and content validity resulted in the removal of 61 items from the initial 151 items. Psychometric testing was applied to the refined 90-item questionnaire administered to participating dietitians, resulting in the final 46-item questionnaire. Six factors were extracted by PCA with varimax rotation explaining 59.2% of the total variance. Partial confirmatory factor analysis showed an acceptable model fit (χ2/df = 2.11, CFI = 0.97, TLI = 0.96, RMSEA = 0.08, SRMR = 0.05). Significant differences were found in sum scores among dietitians with different levels of IBS experience. Internal reliability was >0.7 for each factor. External reliability was >0.6 for each factor and >0.7 for overall items of each domain. CONCLUSION: A validated questionnaire to use in practice and research to assess knowledge, attitudes and practices in the dietary management of IBS has been developed.

Faecal and urine metabolites, but not gut microbiota, may predict response to low FODMAP diet in irritable bowel syndrome.

BACKGROUND: The low FODMAP diet (LFD) leads to clinical response in 50%-80% of patients with irritable bowel syndrome (IBS). It is unclear why only some patients respond. AIMS: To determine if differences in baseline faecal microbiota or faecal and urine metabolite profiles may separate clinical responders to the diet from non-responders allowing predictive algorithms to be proposed. METHODS: We recruited adults fulfilling Rome III criteria for IBS to a blinded randomised controlled trial. Patients were randomised to sham diet with a placebo supplement (control) or LFD supplemented with either placebo (LFD) or 1.8 g/d B-galactooligosaccharide (LFD/B-GOS), for 4 weeks. Clinical response was defined as adequate symptom relief at 4 weeks after the intervention (global symptom question). Differences between responders and non-responders in faecal microbiota (FISH, 16S rRNA sequencing) and faecal (gas-liquid chromatography, gas-chromatography mass-spectrometry) and urine (1 H NMR) metabolites were analysed. RESULTS: At 4 weeks, clinical response differed across the 3groups with adequate symptom relief of 30% (7/23) in controls, 50% (11/22) in the LFD group and 67% (16/24) in the LFD/B-GOS group (p = 0.048). In the control and the LFD/B-GOS groups, microbiota and metabolites did not separate responders from non-responders. In the LFD group, higher baseline faecal propionate (sensitivity 91%, specificity 89%) and cyclohexanecarboxylic acid esters (sensitivity 80%, specificity 78%), and urine metabolite profile (Q2 0.296 vs. randomised -0.175) predicted clinical response. CONCLUSIONS: Baseline faecal and urine metabolites may predict response to the LFD.

Gut Symptoms during FODMAP Restriction and Symptom Response to Food Challenges during FODMAP Reintroduction: A Real-World Evaluation in 21,462 Participants Using a Mobile Application.

BACKGROUND: There is limited evidence regarding the use of low FODMAP diet apps. This study aimed to evaluate the effectiveness of an app intended to reduce symptoms in FODMAP restriction and symptoms and tolerance of high FODMAP food challenges during FODMAP reintroduction and personalisation. METHODS: Data were collected from 21,462 users of a low FODMAP diet app. Self-reported gut symptoms during FODMAP restriction, reintroduction, and personalisation and dietary triggers were identified from symptom response data for FODMAP food challenges. RESULTS: Compared with baseline, at the end of FODMAP restriction, participants (n = 20,553) reported significantly less overall symptoms (11,689 (57%) versus 9105 (44%)), abdominal pain (8196 (40%) versus 6822 (33%)), bloating (11,265 (55%) versus 9146 (44%)), flatulence (10,318 (50%) 8272 (40%)), and diarrhoea (6284 (31%) versus 4961 (24%)) and significantly more constipation (5448 (27%) versus 5923 (29%)) (p < 0.001 for all). During FODMAP reintroduction, participants (n = 2053) completed 8760 food challenges; the five most frequent challenges and n/N (%) of dietary triggers identified were wheat bread 474/1146 (41%), onion 359/918 (39%), garlic 245/699 (35%), milk 274/687 (40%), and wheat pasta 222/548 (41%). The most frequently reported symptoms during food challenges were overall symptoms, abdominal pain, bloating, and flatulence. CONCLUSIONS: In a real-world setting, a low FODMAP diet app can help users improve gut symptoms and detect dietary triggers for long-term self-management.

Development and validation of an inflammatory bowel disease nutrition self-screening tool (IBD-NST) for digital use.

Background and aim: The identification of, and timely intervention for, patients with impaired nutritional status may reduce inflammatory bowel disease (IBD) complications. This study aimed to develop and validate an IBD-specific nutrition self-screening tool (IBD-NST) that identifies patients at nutrition risk. Methods: An expert IBD panel was consulted to support development of an IBD-NST. The tool was assessed in different cohorts of patients attending IBD outpatient clinics for face, content and convergent validity and repeat reliability. The tool was compared with (i) the malnutrition universal screening tool to assess face validity and (ii) subjective global assessment (SGA), hand-grip strength (HGS) and mid-arm muscle circumference to assess convergent validity. Tool content was informed by agreement between assessment tools, sensitivity analysis and chi-squared tests. The IBD-NST was completed electronically twice, 1 week apart to assess repeat reliability using observed agreement and kappa statistic. Statistical significance assumed at p < 0.05. Results: In total, 282 IBD patients (175 with Crohn's disease) were recruited to validate the IBD-NST. The final validated IBD-NST includes body mass index (BMI), weight loss and IBD-specific nutrition-focussed questions which were acceptable to patients. It identified patients at risk of malnutrition, moderately or severely malnourished patients and patients at nutritional risk. The IBD-NST identified 54/179 (30%) patients at moderate or high nutrition risk and had excellent repeat reliability in 85 patients [r = 0.77 (95% CI 0.669 to 0.746)]. Conclusion: The IBD-NST is a self-screening tool, validated for use as either a paper or e-health version, that identifies patients at nutrition risk who are likely to benefit from dietetic assessment and intervention. Furthermore, patients with IBD symptoms who are concerned about their dietary intake can potentially access dietetic care more easily therefore encouraging greater self-management of IBD-related symptoms. The routine use of the IBD-NST as a self-screening tool would enable patient-led care in the outpatient setting and may facilitate timely access to dietetic care.

British Dietetic Association consensus guidelines on the nutritional assessment and dietary management of patients with inflammatory bowel disease.

BACKGROUND: Despite increased awareness of diet and nutrition being integral to the management of patients with inflammatory bowel disease (IBD), there are gaps in the knowledge of IBD healthcare providers regarding nutrition. Furthermore, high quality evidence on nutritional assessment and dietary management of IBD is limited. A Delphi consensus from a panel of experts allows for best-practice guidelines to be developed, especially where high quality evidence is limited. The aim was to develop guidelines for the nutritional assessment and dietary management of IBD using an eDelphi online consensus agreement platform. METHODS: Seventeen research topics related to IBD and nutrition were systematically reviewed. Searches in Cochrane, Embase®, Medline® and Scopus® electronic databases were performed. GRADE was used to develop recommendations. Experts from the IBD community (healthcare professionals and patients with IBD) were invited to vote anonymously on the recommendations in a custom-built online platform. Three rounds of voting were carried out with updated iterations of the recommendations and evaluative text based on feedback from the previous round. RESULTS: From 23,824 non-duplicated papers, 167 were critically appraised. Fifty-five participants completed three rounds of voting and 14 GRADE statements and 42 practice statements achieved 80% consensus. Comprehensive guidance related to nutrition assessment, nutrition screening and dietary management is provided. CONCLUSIONS: Guidelines on the nutritional assessment and dietary management of IBD have been developed using evidence-based consensus to improve equality of care. The statements and practice statements developed demonstrate the level of agreement and the quality and strength of the guidelines.

Improving Food-Related Quality of Life in Inflammatory Bowel Disease through a Novel Web Resource: A Feasibility Randomised Controlled Trial.

Food-related quality of life (FR-QoL) is impaired in inflammatory bowel disease (IBD) and education and support on food-related issues in IBD is needed. This feasibility trial aimed to investigate the effectiveness and acceptability of a web resource in enhancing FR-QoL in newly diagnosed IBD. Patients diagnosed with Crohn's disease or ulcerative colitis in the preceding 12 months, with an impaired FR-QoL, were recruited and randomised to either receive access to the web resource (covering IBD-specific diet concerns) or no access (control group) for 12 weeks, while receiving usual clinical care. FR-QoL, health-related quality of life, psychological outcomes, and clinical disease activity were assessed. Web resource usage was assessed, and patients' experiences of the web resource were investigated in semi-structured interviews. Of 81 patients screened, 50 participants were randomised, 30 to the web resource and 20 to control. FR-QoL increased more in the web resource (+11.7 SD 18.2) than control group (+1.4 SD 20.4) (p = 0.067), while IBD distress reduced in the web resource (-6.8 SD 26.6) and increased in the control group (+8.3 SD 25.5) (p = 0.052), albeit not statistically significantly. End of trial Crohn's disease clinical activity (PRO-2) was significantly lower in the web resource than control group (p = 0.046). Participants most frequently accessed web resource content discussing dietary management of gut symptoms and in semi-structured interviews, reported the website to contain relevant information. This feasibility study demonstrates potential effectiveness of the web resource on improving FR-QoL and psychological outcomes in IBD. An adequately powered effectiveness RCT is feasible to conduct and is now warranted. NCT03884686.

A retrospective cohort study: pre-operative oral enteral nutritional optimisation for Crohn's disease in a UK tertiary IBD centre.

BACKGROUND: Low-quality evidence suggests that pre-operative exclusive enteral nutrition (E/EN) can improve postoperative outcomes in patients with Crohn's disease (CD). It is not standard practice in most centres. AIMS: To test the hypothesis that pre-operative EN in patients undergoing ileal/ileocolonic surgery for CD is associated with improved postoperative outcome. METHODS: We performed a single centre retrospective observational study comparing surgical outcomes in patients receiving pre-operative EN (≥600 kcal/day for ≥2 weeks) with those who received no nutritional optimisation. Consecutive adult patients undergoing ileal/ileocolonic resection from 2008 to 2020 were included. The primary outcome was postoperative complications <30 days. Secondary outcomes included EN tolerance, specific surgical complications, unplanned stoma formation, length of stay, length of bowel resected, readmission and biochemical/anthropometric changes. RESULTS: 300 surgeries were included comprising 96 without nutritional optimisation and 204 optimised cases: oral EN n = 173, additional PN n = 31 (4 of whom had received nasogastric/nasojejunal EN). 142/204 (69.6%) tolerated EN. 125/204 (61.3%) initiated EN in clinic. Patients in the optimised cohort were younger at operation and diagnosis, with an increased frequency of penetrating disease and exposure to antibiotics or biologics, and were more likely to undergo laparoscopic surgery. The optimised cohort had favourable outcomes on multivariate analysis: all complications [OR 0.29; 0.15-0.57, p < 0.001], surgical complications [OR 0.41; 95% CI 0.20-0.87, p = 0.02], non-surgical complications [OR 0.24 95% CI 0.11-0.52, p < 0.001], infective complications [OR 0.32; 95% CI 0.16-0.66, p = 0.001]. CONCLUSIONS: Oral EN was reasonably well tolerated and associated with a reduction in 30-day postoperative complications. Randomised controlled trials are required to confirm these findings.

Long-term personalized low FODMAP diet improves symptoms and maintains luminal Bifidobacteria abundance in irritable bowel syndrome.

BACKGROUND: Short-term trials demonstrate the low FODMAP diet improves symptoms of irritable bowel syndrome (IBS) but impacts nutrient intake and the gastrointestinal microbiota. The aim of this study was to investigate clinical symptoms, nutrient intake, and microbiota of patients with IBS 12 months after starting a low FODMAP diet. METHODS: Participants enrolled in a previous short-term clinical trial and who had been through structured FODMAP restriction, reintroduction, and personalization were invited to participate in a follow-up study at one time point at 12 months. Gastrointestinal symptoms, stool output, dietary intake, and quality of life were recorded. Stool samples were collected and analyzed for microbiota (qPCR) and short-chain fatty acids (SCFA). Data were compared with baseline (prior to any intervention in the original clinical trial) using non-parametric statistics. KEY RESULTS: Eighteen participants were included in the study. Adequate relief of symptoms occurred in 5/18 (28%) at baseline and increased to 12/18 (67%) following long-term personalized low FODMAP diet (p = 0.039). There was a reduction in IBS-SSS total score between baseline (median 227, IQR 99) and long term (154, 89; p < 0.001). Bifidobacteria abundance was not different between baseline (median 9.29 log10 rRNA genes/g, IQR 1.45) and long term (9.20 log10 rRNA genes/g, 1.41; p = 0.766, q = 0.906); however, there were lower concentrations of total SCFA, acetate, propionate, and butyrate. CONCLUSIONS: In this long-term analysis, two thirds of patients reported adequate relief of symptoms after 12 months of personalized low FODMAP diet that did not result in differences from baseline in Bifidobacteria. FODMAP reintroduction and personalization may normalize some of the effects of short-term FODMAP restriction.

Perceived acceptability of partial enteral nutrition (PEN) using oral nutritional supplement drinks in adolescent and adult Crohn's disease outpatients: A feasibility study.

BACKGROUND AND AIMS: Studies, mainly in Japanese cohorts, have shown that partial enteral nutrition (PEN) including oral nutritional supplement (ONS) drinks can prolong disease remission and increase drug effectiveness in Crohn's disease (CD). Acceptability is a key feasibility parameter to determine whether PEN is a viable treatment option in UK CD patients. We report the results of a single centre cross-sectional feasibility study carried out to investigate perceived acceptability of PEN using ONS drinks and whether ONS preference varies with sex, nutritional status or phenylthiocarbamide (PTC) sensitivity. METHODS: Patients with a confirmed CD diagnosis were recruited using convenience sampling from an adult and adolescent gastroenterology outpatient clinic over 3 years. Blind taste testing of 5 polymeric ONS drinks were conducted using a validated 9-point hedonic rating scale followed by completion of an acceptability questionnaire based on the preferred ONS drink. A subset of patients took home the preferred ONS drink for a 7-day ONS study. RESULTS: 105 CD patients (55 males), aged 34.9 (±15.4) years were recruited and 28 patients completed the 7-day ONS study. Overall impression scores did not significantly vary with nutritional status, sex, BMI, handgrip strength (HGS), mid-upper arm circumference (MUAC) or PTC sensitivity. Ensure plus milkshake™ rated highest for overall impression (6.5, p=<0.0001) and all other organoleptic properties (p < 0.0001). The main perceived benefits of using ONS drinks as PEN related to assurance of nutrient intake (89%), convenience (86%), and improvement of gut symptoms (85%). The main perceived barriers related to reduction in pleasure from eating and drinking (56%), struggling with drink storage (54%) having less energy and feeling more tired than if eating 3 solid meals daily (52%). 65% of patients would consider using ONS drinks as PEN as a maintenance treatment option. 81% of patients felt confident-very confident about consuming ONS drinks daily as PEN for three months but this dropped to 64% and 37% at 6 and 12 months, respectively. There was a significant drop in perceived ease of use of ONS drinks as PEN after the 7-day ONS study (P = 0.01). CONCLUSION: Use of ONS drinks as PEN have high perceived benefits and appear to be a feasible option for short-term use of 3-6 months in CD patients. However, confidence in long-term use of ONS drinks as PEN is low mainly due to the perceived social impact. Future studies should assess longer trial periods and volume of ONS drinks to increase the validity of these findings.

Prebiotic Galactooligosaccharide Supplementation in Adults with Ulcerative Colitis: Exploring the Impact on Peripheral Blood Gene Expression, Gut Microbiota, and Clinical Symptoms.

Prebiotics may promote immune homeostasis and reduce sub-clinical inflammation in humans. This study investigated the effect of prebiotic galactooligosaccharide (GOS) supplementation in colonic inflammation. Seventeen patients with active ulcerative colitis (UC) consumed 2.8 g/d GOS for 6 weeks. At baseline and 6 weeks, gene expression (microarray), fecal calprotectin (ELISA), microbiota (16S rRNA), short-chain fatty acids (SCFAs; gas-liquid chromatography), and clinical outcomes (simple clinical colitis activity index (SCCAI), gastrointestinal symptom rating scale (GSRS), and Bristol stool form scale (BSFS)) were measured. Following prebiotics, clinical scores (SCCAI), fecal calprotectin, SCFAs, and pH were unchanged. Five genes were upregulated and two downregulated. Normal stool proportion (BSFS) increased (49% vs. 70%, p = 0.024), and the incidence (46% vs. 23%, p = 0.016) and severity (0.7 vs. 0.5, p = 0.048) of loose stool (GSRS), along with urgency (SCCAI) scores (1.0 vs. 0.5, p = 0.011), were reduced. In patients with a baseline SCCAI ≤2, prebiotics increased the relative abundance of Bifidobacterium from 1.65% (1.97) to 3.99% (5.37) (p = 0.046) and Christensenellaceae from 0.13% (0.33) to 0.31% (0.76) (p = 0.043). Prebiotics did not lower clinical scores or inflammation but normalized stools. Bifidobacterium and Christensenellaceae proportions only increased in patients with less active diseases, indicating that the prebiotic effect may depend on disease activity. A controlled study is required to validate these observations.

Food-related quality of life is impaired in inflammatory bowel disease and associated with reduced intake of key nutrients.

BACKGROUND: Inflammatory bowel disease (IBD) may impact the extent to which food, eating, and drinking bring satisfaction and enjoyment to peoples' lives, and this may impact dietary intake. The prevalence of an impaired food-related quality of life (FR-QoL), its associated factors, and its impact on diet have not been explored. OBJECTIVES: To measure the prevalence and nature of the burden of impaired FR-QoL in people with IBD, the factors associated with these, and their associations with nutrient intake. METHODS: We recruited 1576 outpatients with IBD (≥16 years old) in person from 7 IBD centers across the United Kingdom. Patients completed validated questionnaires to measure their FR-QoL, quality of life (QoL), distress, fatigue, anxiety, and depression. Dietary intake was recorded using the European Prospective Investigation into Cancer FFQ. A health professional recorded disease activity, Montreal classification, blood results, BMI, and malnutrition risk. FR-QoL was regressed onto explanatory variables using univariable and multivariable analyses. RESULTS: Data from 1221 patients were available (77.4% response; Crohn's disease, 65%; ulcerative colitis, 35%). The FR-QoL mean (± SD) score was 80.8 ± 26.9, with wide ranges (minimum, 29; maximum, 145). Following multivariable regression, the strongest associations with FR-QoL were the number of recent disease flares (5 flares ß = -12.7; P < 0.001), the IBD-specific QoL (ß = 0.33; P < 0.001), and IBD-related distress (ß = -0.26; P < 0.001). Patients with poorer FR-QoL had lower intakes of fiber (nonstarch polysaccharide; Q1 to Q5 difference = 2.1 g/d; 95% CI: 0.4-3.8; P = 0.048), calcium (192.6 mg/d; 95% CI: 112.5-272.6; P < 0.001), phosphorus (167 mg/d; 95% CI: 58-276; P = 0.041), and magnesium (34.4 mg/d; 95% CI: 9.3-59.4; P = 0.041). CONCLUSIONS: Impaired FR-QoL is prevalent in IBD and is associated with recurrent disease flares, a reduced IBD-specific QoL, and greater IBD-related distress. A poorer FR-QoL was associated with lower intakes of key nutrients of importance to IBD, including those relating to gut health and bone mineralization.

Gut microbiota associations with diet in irritable bowel syndrome and the effect of low FODMAP diet and probiotics.

BACKGROUND AND AIMS: Diet is both a modulator of the gastrointestinal microbiota and an important therapy in irritable bowel syndrome (IBS). We aimed to comprehensively (i) identify diet-microbiota associations in adults with IBS consuming habitual diet; (ii) assess the impact of two nutritional interventions on the microbiota; and (iii) determine whether baseline microbiota can predict clinical response to diet or probiotic intervention. METHODS: Data were analyzed from 95 individuals with IBS participating in a previously published 4-week 2x2 factorial design randomized controlled trial investigating the impact of the low FODMAP diet (LFD) and co-administration of a probiotic. Diet was assessed at four hierarchical levels and partial 16S rRNA gene sequencing was used to profile the microbiota. RESULTS: There were numerous diet-microbiota associations especially at the nutrient level, including a negative association between protein and Bifidobacterium abundance (rs = -0.358, p < 0.001). After correction for multiple testing, the significance for this association (q = 0.237) and all others was lost. Low FODMAP diet led to changes in abundance of major saccharolytic genera compared with sham diet, including higher Bacteroides (LFD 34.1% (15.7%) vs sham 23.3% (15.2%), q = 0.01) and lower Bifidobacterium (0.9% (1.0%) vs 2.1%, (2.5%) q = 0.029). Compared with placebo, probiotic supplementation led to higher Lactobacillus (probiotic 0.08% (0.1%) vs placebo 0.03% (0.2%), q < 0.001), and Streptococcus abundance (2.0% (2.2%) vs 0.6% (1.2%), q = 0.001). The probiotic treatment buffered the impact of the low FODMAP diet on Bifidobacterium. Baseline microbiota did not predict clinical response to either intervention. CONCLUSIONS: Although diet modifies the gut microbiota, bivariate correlation analysis may only provide a limited explanation of the complex diet interactions with individual gut bacteria in IBS. Some diet interventions modify the microbiota in IBS. TRIAL REGISTRY: ISRCTN (http://www.isrctn.com) Registered under ISRCTN registry identifier no.ISRCTN02275221.

Processing Apples to Puree or Juice Speeds Gastric Emptying and Reduces Postprandial Intestinal Volumes and Satiety in Healthy Adults.

BACKGROUND: Whole apples produce greater satiety than processed apples, but the underlying mechanisms remain unclear. OBJECTIVE: Our aim was to assess the intragastric processing of apple preparations and the associated small and large bowel contents using MRI. METHODS: An open label, 3-way crossover, randomized, controlled trial. Eighteen healthy adults (mean ± SD age, 25 ± 4 y; BMI, 22.7 ± 3.5 kg/m2) underwent serial MRI scans on 3 occasions separated by 7 d, after consumption of isocaloric (178 kcal) portions of either whole apples, apple puree, or apple juice. Gastric emptying, small bowel water content (SBWC; primary endpoint), were measured at baseline and at 45 min intervals (0-270 min) postmeal ingestion. Fullness and satiety were also assessed at each time point. Treatment effects between groups were analyzed using ANOVA. RESULTS: Gastric emptying half-time (GE t50) was greater (P < 0.0001) after participants consumed whole apple (mean ± SEM), 65 (3.3) min compared with when they consumed apple puree (41 [2.8] min) or apple juice (38 [2.9] min), times that did not differ. Postprandial area under the curve (AUC) (135-270 min) SBWC was also greater for whole apples than puree (P = 0.025) and juice (P = 0.0004) but juice and puree did not differ. AUC for fullness and satiety (0-270 min) postingestion was also greater (P = 0.002 and 0.004, respectively) for whole apple compared with juice but juice and puree did not differ. CONCLUSIONS: Gastric emptying is slower after whole apple consumption causing a greater sensation of fullness and satiety than puree or juice in healthy adults. Whole apples increased small bowel and colonic contents during the later phase of the study which may be relevant for subsequent food consumption.This study was registered at clinicaltrials.gov as NCT03714464.

ß-Galactooligosaccharide in Conjunction With Low FODMAP Diet Improves Irritable Bowel Syndrome Symptoms but Reduces Fecal Bifidobacteria.

INTRODUCTION: The low FODMAP diet (LFD) reduces symptoms and bifidobacteria in irritable bowel syndrome (IBS). ß-galactooligosaccharides (B-GOS) may reduce the symptoms and increase bifidobacteria in IBS. We investigated whether B-GOS supplementation alongside the LFD improves IBS symptoms while preventing the decline in bifidobacteria. METHODS: We performed a randomized, placebo-controlled, 3-arm trial of 69 Rome III adult patients with IBS from secondary care in the United Kingdom. Patients were randomized to a sham diet with placebo supplement (control) or LFD supplemented with either placebo (LFD) or 1.4 g/d B-GOS (LFD/B-GOS) for 4 weeks. Gastrointestinal symptoms, fecal microbiota (fluorescent in situ hybridization and 16S rRNA sequencing), fecal short-chain fatty acids (gas-liquid chromatography) and pH (probe), and urine metabolites (H NMR) were analyzed. RESULTS: At 4 weeks, adequate symptom relief was higher in the LFD/B-GOS group (16/24, 67%) than in the control group (7/23, 30%) (odds ratio 4.6, 95% confidence interval: 1.3-15.6; P = 0.015); Bifidobacterium concentrations (log10 cells/g dry weight) were not different between LFD and LFD/B-GOS but were lower in the LFD/B-GOS (9.49 [0.73]) than in the control (9.77 [0.41], P = 0.018). A proportion of Actinobacteria was lower in LFD (1.9%, P = 0.003) and LFD/B-GOS (1.8%, P < 0.001) groups than in the control group (4.2%). Fecal butyrate was lower in the LFD (387.3, P = 0.028) and LFD/B-GOS (346.0, P = 0.007) groups than in the control group (609.2). DISCUSSION: The LFD combined with B-GOS prebiotic produced a greater symptom response than the sham diet plus placebo, but addition of 1.4 g/d B-GOS did not prevent the reduction of bifidobacteria. The LFD reduces fecal Actinobacteria and butyrate thus strict long-term use should not be advised.

Perioperative Dietary Therapy in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: The incidence of inflammatory bowel disease [IBD] is rising worldwide and no cure is available. Many patients require surgery and they often present with nutritional deficiencies. Although randomised controlled trials of dietary therapy are lacking, expert IBD centres have long-established interdisciplinary care, including tailored nutritional therapy, to optimise clinical outcomes and resource utilisation. This topical review aims to share expertise and offers current practice recommendations to optimise outcomes of IBD patients who undergo surgery. METHODS: A consensus expert panel consisting of dietitians, surgeons, and gastroenterologists, convened by the European Crohn's and Colitis Organisation, performed a systematic literature review. Nutritional evaluation and dietary needs, perioperative optimis ation, surgical complications, long-term needs, and special situations were critically appraised. Statements were developed using a Delphi methodology incorporating three successive rounds. Current practice positions were set when ≥80% of participants agreed on a recommendation. RESULTS: A total of 26 current practice positions were formulated which address the needs of IBD patients perioperatively and in the long term following surgery. Routine screening, perioperative optimisation by oral, enteral, or parenteral nutrition, dietary fibre, and supplements were reviewed. IBD-specific situations, including management of patients with a restorative proctocolectomy, an ostomy, strictures, or short-bowel syndrome, were addressed. CONCLUSIONS: Perioperative dietary therapy improves the outcomes of IBD patients who undergo a surgical procedure. This topical review shares interdisciplinary expertise and provides guidance to optimise the outcomes of patients with Crohn's disease and ulcerative colitis. taking advantage of contemporary nutrition science.

Effects of Low FODMAP Diet on Symptoms, Fecal Microbiome, and Markers of Inflammation in Patients With Quiescent Inflammatory Bowel Disease in a Randomized Trial.

BACKGROUND & AIMS: There is limited evidence that a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) reduces gut symptoms in quiescent inflammatory bowel disease (IBD). We performed a randomized, controlled trial to investigate the effects of a low FODMAP diet on persistent gut symptoms, the intestinal microbiome, and circulating markers of inflammation in patients with quiescent IBD. METHODS: We performed a single-blind trial of 52 patients with quiescent Crohn's disease or ulcerative colitis and persistent gut symptoms at 2 large gastroenterology clinics in the United Kingdom. Patients were randomly assigned to groups that followed a diet low in FODMAPs (n = 27) or a control diet (n = 25), with dietary advice, for 4 weeks. Gut symptoms and health-related quality of life were measured using validated questionnaires. Stool and blood samples were collected at baseline and end of trial. We assessed fecal microbiome composition and function using shotgun metagenomic sequencing and phenotypes of T cells in blood using flow cytometry. RESULTS: A higher proportion of patients reported adequate relief of gut symptoms following the low FODMAP diet (14/27, 52%) than the control diet (4/25, 16%, P=.007). Patients had a greater reduction in irritable bowel syndrome severity scores following the low FODMAP diet (mean reduction of 67; standard error, 78) than the control diet (mean reduction of 34; standard error, 50), although this difference was not statistically significant (P = .075). Following the low FODMAP diet, patients had higher health-related quality of life scores (81.9 ± 1.2) than patients on the control diet (78.3 ± 1.2, P = .042). A targeted analysis revealed that in stool samples collected at the end of the study period, patients on the low FODMAP diet had significantly lower abundance of Bifidobacterium adolescentis, Bifidobacterium longum, and Faecalibacterium prausnitzii than patients on control diet. However, microbiome diversity and markers of inflammation did not differ significantly between groups. CONCLUSIONS: In a trial of the low FODMAP diet vs a control diet in patients with quiescent IBD, we found no significant difference after 4 weeks in change in irritable bowel syndrome severity scores, but significant improvements in specific symptom scores and numbers reporting adequate symptom relief. The low FODMAP diet reduced fecal abundance of microbes believed to regulate the immune response, compared with the control diet, but had no significant effect on markers of inflammation. We conclude that a 4-week diet low in FODMAPs is safe and effective for managing persistent gut symptoms in patients with quiescent IBD. www.isrctn.com no.: ISRCTN17061468.

Nutrient Intake, Diet Quality, and Diet Diversity in Irritable Bowel Syndrome and the Impact of the Low FODMAP Diet.

BACKGROUND: Individuals with irritable bowel syndrome (IBS) may modify their diet, which may pose nutritional risk. Further, some dietary approaches, such as a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), are restrictive and may contribute to nutritional inadequacy. OBJECTIVE: Our aim was to evaluate habitual nutrient intake, diet quality, and diversity in IBS and the effect of a 4-week low FODMAP diet on these parameters compared with controls. DESIGN: Data from two randomized controlled trials were included for this secondary analysis. Participants were randomized to low FODMAP diet (n=63) or control diet (sham diet n=48, habitual diet n=19). PARTICIPANTS/SETTING: Participants included 130 individuals with IBS referred to a tertiary center in London, UK between January 2010 to June 2011 and January 2013 to November 2014. INTERVENTION: Participants in one trial were randomized to receive either low FODMAP dietary counseling or sham control dietary counseling. In the other, they were randomized to receive low FODMAP dietary counseling or to continue habitual diet. All advice was provided by a specialist dietitian. MAIN OUTCOME MEASURES: Habitual (usual) dietary intake at baseline (n=130) and after a 4-week intervention period was measured using 7-day food records. STATISTICAL ANALYSES PERFORMED: Analysis of covariance and χ2 tests evaluated differences across groups at 4 weeks. RESULTS: When examining habitual intake of individuals with IBS, fiber intake was low, with only 6 (5%) achieving the target (30 g/day). In those receiving low FODMAP advice, there was no difference in intake of most nutrients compared with controls. However, there was lower intake of starch (109 g/day) vs habitual control diet (128 g/day; P=0.030), and higher intake of vitamin B-12 (6.1 µg/day) vs habitual (3.9 µg/day) and sham control diets (4.7 µg/day; P<0.01). Overall scores for diet quality were lower after low FODMAP advice vs habitual control diet (P<0.01). CONCLUSION: This study demonstrates many individuals with IBS fail to meet dietary reference values for multiple nutrients. A 4-week low FODMAP diet, when delivered by a specialist dietitian, does not impact on intake of most nutrients or diet diversity but decreases diet quality compared with control diets.

Nutrition Assessment in Crohn's Disease using Anthropometric, Biochemical, and Dietary Indexes: A Narrative Review.

Malnutrition is common in patients with Crohn's disease and negatively influences immunity and quality of life. The optimal tools for nutrition assessment in patients with Crohn's disease are not clearly defined and lead to variations in practice. With this review, we aimed to appraise the existing evidence for nutrition assessment of patients with Crohn's disease compared with healthy controls and provide a comprehensive guide with relevant measures applicable to clinical practice. A literature search using Medline, Embase, and Scopus from inception to October 1, 2018, was conducted. Forty-one articles that assessed body composition, muscle strength, micronutrient status and/or dietary intake in adults with Crohn's disease compared with an age- and sex-matched healthy individuals were included. There were heterogeneous findings on nutritional status in patients with Crohn's disease compared with healthy controls. Only one article reported a clinically significant difference for body mass index; however, significant deficits in fat mass, fat-free mass, and muscle strength were observed in patients with Crohn's disease compared with healthy controls, with more pronounced differences with increasing disease activity and length of diagnosis. Most research reported significantly lower serum micronutrients in patients with Crohn's disease compared with healthy controls. Half of studies measuring micronutrient intake reported lower intakes in patients with Crohn's disease compared with healthy controls. Fruit and vegetable intake was also lower in patients with Crohn's disease. Difficulties characterizing the type and prevalence of malnutrition exist due to the heterogeneous nature of Crohn's disease and warrants continued investigation. As a result of this review, we advocate that a nutrition assessment should include more parameters than weight and body mass index.