Evolution, adaptation, and new applications of the FODMAP diet.

The FODMAP diet has been a treatment of irritable bowel syndrome (IBS) for many years. Rigorous scientific evaluation and clinical application of the FODMAP diet have generated deep understanding regarding clinical efficacy, mechanisms of action, and potential adverse effects of this dietary approach. In turn, this knowledge has allowed fine-tuning of the diet to optimize treatment benefits and minimize risks, in the form of the traditional three-phase diet; the FODMAP-gentle approach, which is a less restrictive iteration; and a proposed FODMAP-modified, Mediterranean-style diet which endeavours to optimise both gastrointestinal symptoms and other health parameters. Furthermore, recognition that IBS-like symptoms feature in other conditions has seen the FODMAP diet tested in non-IBS populations, including in older adults with diarrhea and women with endometriosis. These areas represent new frontiers for the FODMAP diet and a space to watch as future research evaluates the validity of these novel clinical applications.

Role of diet in prevention versus treatment of Crohn's disease and ulcerative colitis.

Diet is a modifiable risk factor for disease course and data over the past decade have emerged to indicate its role in Crohn's disease (CD) and ulcerative colitis (UC). However, literature is riddled with misinterpretation of data, often leading to unexpected or conflicting results. The key understanding is that causative factors in disease development do not always proceed to an opportunity to change disease course, once established. Here, we discuss the data on dietary influences in three distinct disease states for CD and UC-predisease, active disease and quiescent disease. We appraise the literature for how our dietary recommendations should be shaped to prevent disease development and if or how that differs for CD and UC induction therapy and maintenance therapy. In UC, principles of healthy eating are likely to play a role in all states of disease. Conversely, data linking dietary factors to CD prevention and treatment are paradoxical with the highest quality evidence for CD treatment being exclusive enteral nutrition, a lactose, gluten and fibre-free diet comprising solely of ultraprocessed food-all dietary factors that are not associated or inversely associated with CD prevention. High-quality evidence from dietary trials is much awaited to expand our understanding and ultimately lead our dietary recommendations for targeted patient populations.

Characterisation of biomarkers of intestinal barrier function in response to a high fat/high carbohydrate meal and corticotropin releasing hormone.

BACKGROUND: Variation of circulating concentrations of putative biomarkers of intestinal barrier function over the day and after acute physiological interventions are poorly documented on humans. This study aimed to examine the stability and pharmacokinetics of changes in plasma concentrations of intestinal Fatty-acid -binding -protein (IFABP), Lipopolysaccharide-binging-protein (LBP), soluble CD14, and Syndecan-1 after acute stress and high fat-high-carbohydrate meal. METHODS: In a single-blinded, cross-over, randomised study, healthy volunteers received on separate days corticotropin-releasing hormone (CRH, 100 µg) or normal saline (as placebo) intravenously in random order, then a HFHC meal. Participants were allowed low caloric food. Markers of intestinal barrier function were measured at set timed intervals from 30 minutes before to 24 hours after interventions. RESULTS: 10 participants (50% female) completed all three arms of the study. IFABP decreased by median 3.6 (IQR 1.4-10)% from -30 minutes to zero time (p = 0.001) and further reduced by 25 (20-52)% at 24 hours (p = 0.01) on the low caloric diet, but did not change in response to the meal. Syndecan-1, LBP and sCD14 were stable over a 24-hour period and not affected acutely by food intake. LBP levels 2 hours after CRH reduced by 0.61 (-0.95 to 0.05) µg/ml compared with 0.16 (-0.3 to 0.5) µg/ml post placebo injection (p = 0.05), but other markers did not change. CONCLUSION: Concentrations of IFABP, but not other markers, are unstable over 24 hours and should be measured fasting. A HFHC meal does not change intestinal permeability. Transient reduction of LPB after CRH confirms acute barrier dysfunction during stress.

Review article: Current status and future directions of ingestible electronic devices in gastroenterology.

BACKGROUND: Advances in microelectronics have greatly expanded the capabilities and clinical potential of ingestible electronic devices. AIM: To provide an overview of the structure and potential impact of ingestible devices in development that are relevant to the gastrointestinal tract. METHODS: We performed a detailed literature search to inform this narrative review. RESULTS: Technical success of ingestible electronic devices relies on the ability to miniaturise the microelectronic circuits, sensors and components for interventional functions while being sufficiently powered to fulfil the intended function. These devices offer the advantages of being convenient and minimally invasive, with real-time assessment often possible and with minimal interference to normal physiology. Safety has not been a limitation, but defining and controlling device location in the gastrointestinal tract remains challenging. The success of capsule endoscopy has buoyed enthusiasm for the concepts, but few ingestible devices have reached clinical practice to date, partly due to the novelty of the information they provide and also due to the challenges of adding this novel technology to established clinical paradigms. Nonetheless, with ongoing technological advancement and as understanding of their potential impact emerges, acceptance of such technology will grow. These devices have the capacity to provide unique insight into gastrointestinal physiology and pathophysiology. Interventional functions, such as sampling of tissue or luminal contents and delivery of therapies, may further enhance their ability to sharpen gastroenterological diagnoses, monitoring and treatment. CONCLUSIONS: The development of miniaturised ingestible microelectronic-based devices offers exciting prospects for enhancing gastroenterological research and the delivery of personalised, point-of-care medicine.

IBD barriers across the continents: a continent-specific analysis - Australasia.

Australasia, encompassing Australia, New Zealand, and Papua New Guinea, has some of the highest prevalence's of inflammatory bowel disease (IBD) in the world. The way IBD medicine is practiced varies between and within these countries. There are numerous shared issues of IBD care between Australia and New Zealand, whereas Papua New Guinea has its' own unique set of circumstances. This review looks to explore some of the barriers to IBD care across the continent from the perspective of local IBD healthcare professionals. Barriers to IBD care that are explored include access to IBD multidisciplinary teams, provision of nutritional-based therapies, the prevalence and engagement of IBD-associated mental health disorders, access to medicine, access to endoscopy, rural barriers to care, Indigenous IBD care and paediatric issues. We look to highlight areas where improvements to IBD care across Australasia could be made as well as address research needs.

Review article: Mechanisms underlying the effectiveness of exclusive enteral nutrition in Crohn's disease.

BACKGROUND: Exclusive enteral nutrition (EEN) induces remission and mucosal healing in patients with Crohn's disease, but the mechanism of action remains unknown. AIM: To outline current understanding of the mechanisms of action of EEN. METHODS: From a comprehensive literature search, published data were critically examined in a narrative review. RESULTS: Multiple potential mechanisms of action have been identified. EEN optimises nutritional status. Differences in gut microbiota in terms of overall diversity and taxonomic community structure are observed between responders and non-responders to EEN. Therapy with EEN alters microbial metabolites (including faecal short-chain fatty acids, amino acids, branched-chain amino acids and sulphide) and faecal pH. Epithelial effects and restoration of barrier function, as well as changes in mucosal cytokine profiles and T-cell subsets are observed in responders to EEN. The impact of inclusion or exclusion of specific dietary components may be of importance, but putative detrimental components are found in many formulas. A major challenge in interpreting these findings is that they often contradict or change in opposite directions to what is considered 'beneficial'. It is difficult to differentiate between the observations following EEN being driven by EEN per se and those associated with resolving inflammation. CONCLUSIONS: The mechanisms of action of EEN are likely to involve a complex interplay between host mucosal immune response and luminal environment, but the identity of key factors remains poorly understood. A better definition of pathogenic factors may aid in developing more targeted dietary treatment and provide insights into the pathogenesis of Crohn's disease.

Smartphone app-delivered gut-directed hypnotherapy improves symptoms of self-reported irritable bowel syndrome: A retrospective evaluation.

BACKGROUND: Gut-directed hypnotherapy (GDH) has high rates of durable efficacy for treating irritable bowel syndrome (IBS) but its widespread use is limited due to high costs and poor access. A smartphone app delivering GDH was developed to fill gaps in accessibility but has not been assessed in IBS patients. The current retrospective evaluation aims to assess the efficacy of app-delivered GDH in managing IBS symptoms and to investigate associating factors that predict response. METHODS: Irritable bowel syndrome patients who downloaded the app between June 2019 and April 2020 were retrospectively evaluated. The first seven sessions were free. Daily GDH, psycho-education, and breathing exercises were included. Overall and individual gastrointestinal symptoms were assessed at baseline and completion using a 100-mm visual analogue scale. Clinical data were extracted. KEY RESULTS: 2843 patients with self-reported IBS commenced the free sessions, 1428 (50%) purchased the app and 253 (9%) completed all 42 sessions. Outcome data were available for 190 users who completed all 42 sessions. 64% of patients who completed the GDH and provided outcome data responded (defined as >30% reduction in abdominal pain). Abdominal pain reduced from 60mm (50-73mm) at baseline to 26mm (13-50mm) on study completion (p<0.001 Wilcoxon). Similar results were seen for overall and individual symptoms. On multivariable analysis, symptom response was positively associated with being ≥ 40 years (estimated OR 0.398, p=0.025) and negatively associated with trying probiotics (0.323, p=0.042). CONCLUSIONS & INFERENCES: Adherence to app-delivered gut-directed hypnotherapy was low but users who completed the program saw notable improvements in their IBS symptoms. Patients ≥40 years, with symptoms for ≥5 years, may respond better. A controlled trial comparing face-to-face to app-delivered GDH is indicated.

Lessons from an audit of exclusive enteral nutrition in adult inpatients and outpatients with active Crohn's disease: a single-centre experience.

Objective: To evaluate clinical outcomes, patterns of use, tolerance and nutritional outcomes of exclusive enteral nutrition (EEN) in adults with Crohn's disease and to compare initiation in the inpatient compared with ambulatory care setting. Design/method: Adults with Crohn's disease who received EEN at a single centre over 2.5 years were identified and outcomes assessed via examination of patient records. Results: EEN was initiated in 60 patients (23 as an outpatient) who had objective evidence of active disease. Of 49 in whom the goal was induction of remission, 28 completed EEN and 24 achieved clinical remission/response. Twenty-one withdrew prematurely, due to intolerance in 15 and disease factors in 6. Of 11 with a planned intervention, 6 fulfilled the goal of downstaging disease while two were intolerant. Completion of the prescribed therapy was associated with self-reported adherence to EEN and with improvements in disease activity scores and biochemical markers. Malnutrition halved (40% to 20%) and intentional weight loss (median 5.1 kg) was achieved in six obese patients. The major reason for intolerance was the inability to accept total avoidance of non-formula food. There were no differences in any outcomes according to the location of initiation of therapy. Conclusion: Positive outcomes occur in 70% of adult patients with Crohn's disease tolerating EEN and 81% in those who are able to completely adhere to EEN, without compromise of nutritional status. Similar success occurs when initiated as an inpatient or outpatient. Failure to tolerate EEN is the major hurdle to its use.

Application of The FODMAP Diet in a Paediatric Setting.

In adults, dietary management, particularly with the FODMAP diet, is a key evidence-based part of multimodal therapy for patients with disorders of the gut-brain interaction, particularly irritable bowel syndrome. This review aims to describe the evidence for the use of this diet and how to deliver it in paediatric practice. A literature review covering studies on the FODMAP diet in adult and paediatric settings was conducted. While the evidence for the efficacy and safety of a FODMAP diet delivered in three phases, restriction, rechallenge and personalisation, is considerable, there is a lack of good-quality clinical trials exploring the efficacy of the diet in children and adolescents. Likewise, there are limited data on safety concerns associated with a restrictive diet in paediatrics, including impacts on nutrition and growth, disordered eating behaviours, psychosocial and family issues and families and the gut microbiome. The evidence suggests that the implementation of a dietary program is enhanced by a skilled dietitian when navigating a young person (and family) through healthy eating strategies and/or FODMAP restrictions to ameliorate their symptoms. Since the FODMAP diet is being prescribed globally to children, a practical guide for clinicians used to optimise efficacy and safety is provided, including the less restrictive 'FODMAP-gentle' diet.

How to Implement the 3-Phase FODMAP Diet Into Gastroenterological Practice.

Background/Aims: The 3-phase fermentable oligo-, di-, mono-saccharides, and polyols (FODMAP) diet has shown a high level of efficacy in irritable bowel syndrome, largely based on dietitian delivered education. However, access to dietitians can be limited, and challenges exist when applying the diet to a wide range of cultures, such as limited FODMAP analysis of local foods. This review aims to discuss ways to optimally use the FODMAP diet in practice in a wide range of cultures, directed at gastroenterologists from a dietitian's perspective. Methods: Recent literature was analysed via search databases including Medline, CINAHL, PubMed and Scopus. Results: The dietetic process involves detailed assessment and follow-up through the 3 stages of the FODMAP diet (restriction, re-introduction, and long-term maintenance). Emerging evidence suggests the diet can be delivered by other health professionals such as the gastroenterologist or nurse, but training on how to do so successfully would be needed. Self-guided approaches through use of technology or specialised food delivery services may be an alternative when dietitians are not available, but efficacy data is limited. Regardless of delivery mode, nutritional and psychological risks of the diet must be mitigated. Additionally, culturally appropriate education must be provided, with accommodations necessary when the FODMAP content of local foods are unknown. Conclusion: While the diet has shown improved irritable bowel syndrome outcomes across studies, it is important to acknowledge the essential role of dietitians in implementing, tailoring, and managing the diet to achieve the best outcome for each individual.

Dietary management of adults with IBD - the emerging role of dietary therapy.

Historically, dietitians played a minor part in the management of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Patients were commonly referred for consequences of uncontrolled disease, such as malnutrition and bowel obstruction risk. Today, dietitians are fundamental members of the multidisciplinary IBD team, from educating on the role of diet at diagnosis and throughout the lifespan of a patient with IBD to guiding primary induction therapy. This aspect is reflected in published guidelines for IBD management, which previously placed diet as only a minor factor, but now have diet-specific publications. This Review describes a four-step approach in a dietitian's assessment and management of diet in patients with IBD: (1) identifying and correcting nutritional gaps and dietary imbalances; (2) considering diet to treat active disease with the use of exclusive enteral nutrition (EEN) or emerging diets that could replace EEN; (3) using therapeutic diets to control existing complications of IBD, such as reduced fibre to prevent bowel obstruction in stricturing disease or a fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet to manage co-existing functional gut symptoms; and (4) considering the role of diet in preventing IBD development in high-risk populations.

Diet as a therapeutic tool in chronic gastrointestinal disorders: Lessons from the FODMAP journey.

BACKGROUND AND AIM: Diet is a powerful tool in the management of gastrointestinal disorders, but developing diet therapies is fraught with challenge. This review discusses key lessons from the FODMAP diet journey. METHODS: Published literature and clinical experience were reviewed. RESULTS: Key to designing a varied, nutritionally adequate low-FODMAP diet was our accurate and comprehensive database of FODMAP composition, made universally accessible via our user-friendly, digital application. Our discovery that FODMAPs coexist with gluten in cereal products and subsequent gluten/fructan challenge studies in nonceliac gluten-sensitive populations highlighted issues of collinearity in the nutrient composition of food and confirmation bias in the interpretation of dietary studies. Despite numerous challenges in designing, funding, and executing dietary randomized controlled trials, efficacy of the low-FODMAP diet has been repeatedly demonstrated, and confirmed by real-world experience, giving this therapy credibility in the eyes of clinicians and researchers. Furthermore, real-world application of this diet saw the evolution of a safe and effective three-phased approach. Specialist dietitians must deliver this diet to optimize outcomes as they can target and tailor the therapy and to mitigate the key risks of compromising nutritional adequacy and precipitating disordered eating behaviors, skills outside the gastroenterologist's standard tool kit. While concurrent probiotics are ineffective, specific fiber supplements may improve short-term and long-term outcomes. CONCLUSIONS: The FODMAP diet is highly effective, but optimal outcomes are contingent on the involvement of a gastroenterological dietitian who can assess, educate, and monitor patients and manage risks associated with implementation of this restrictive diet.