Review of exclusive enteral therapy in adult Crohn's disease

The Impact of Dietary Interventions on the Microbiota in Inflammatory Bowel Disease: A Systematic Review

BACKGROUND AND AIMS

Diet plays an integral role in the modulation of the intestinal environment, with the potential to be modified for management of individuals with inflammatory bowel disease [IBD]. It has been hypothesised that poor 'Western-style' dietary patterns select for a microbiota that drives IBD inflammation and, that through dietary intervention, a healthy microbiota may be restored. This study aimed to systematically review the literature and assess current available evidence regarding the influence of diet on the intestinal microbiota composition in IBD patients, and how this may affect disease activity.

METHODS

MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library were searched from January 2013 to June 2023, to identify studies investigating diet and microbiota in IBD.

RESULTS

Thirteen primary studies met the inclusion criteria and were selected for narrative synthesis. Reported associations between diet and microbiota in IBD were conflicting due to the considerable degree of heterogeneity between studies. Nine intervention studies trialled specific diets and did not demonstrate significant shifts in the diversity and abundance of intestinal microbial communities or improvement in disease outcomes. The remaining four cross-sectional studies did not find a specific microbial signature associated with habitual dietary patterns in IBD patients.

CONCLUSIONS

Diet modulates the gut microbiota, and this may have implications for IBD; however, the body of evidence does not currently support clear dietary patterns or food constituents that are associated with a specific microbiota profile or disease marker in IBD patients. Further research is required with a focus on robust and consistent methodology to achieve improved identification of associations.

Use of oral diet and nutrition support in management of stricturing and fistulizing Crohn's disease

Crohn's disease (CD), a form of inflammatory bowel disease, involves chronic inflammation within the gastrointestinal tract. Intestinal strictures and fistulas are common complications of CD with varying severity in their presentations. Modifications in oral diet or use of exclusive enteral nutrition (EEN) are common approaches to manage both stricturing and fistulizing disease, although supporting research evidence is generally limited. In the preoperative period, there is strong evidence that EEN can reduce surgical complications. Parenteral nutrition (PN) is often utilized in the management of enterocutaneous fistulas, given that oral diet and EEN may potentially increase output in proximal fistulas. This narrative review highlights the current practices and evidence for the roles of oral diet, EEN, and PN in treatment and management of stricturing and fistulizing CD.

"Out of the box" new therapeutic strategies for Crohn´s disease: moving beyond biologics

New treatment options beyond immunosuppression have emerged in recent years for patients with Crohn´s disease (CD), a chronic systemic condition affecting primarily the gut with great impact in the quality of life. The cause of CD is largely unknown, and a curative treatment is not yet available. In addition, despite the growing therapeutic armamentarium in recent years almost half of the patients don´t achieve a sustained response over time. Thus, new therapeutic strategies are urgently needed. In this review, we discuss the current state of promising new "out of the box" possibilities to control chronic inflammation beyond current pharmacological treatments, including: exclusive enteral nutrition, specific diets, cell therapies using T regs, hyperbaric oxygen, fecal microbiota transplantation, phage therapy, helminths, cannabis and vagal nerve stimulation. The exploration of original and novel therapeutic modalities is key to address their potential as main or complementary treatments in selected CD populations in order to increase efficacy, minimize side effects and improve quality of life of patients.

Plant-based Diets for Inflammatory Bowel Disease: What Is the Evidence?

BACKGROUND

Inflammatory bowel disease is a chronic incurable condition that carries a high morbidity burden for patients. Plant-based diets have emerged as a potentially safe and effective treatment strategy for this condition. However, no attempt has been made to summarize the literature in this field. In this review, we aim to define variants of plant-based diets that have been studied, evaluate their findings, and identify knowledge gaps that warrant further investigation.

METHODS

A literature search was conducted on MEDLINE and Embase.

RESULTS

Twenty-three studies with 2304 participants were included in this review. Eleven studies (48%) were case reports and 8 (35%) were single-arm trials. Semivegetarian diets were the most commonly studied plant-based diet (n = 14, 61%). Most studies reported that plant-based diets were safe and effective in managing inflammatory bowel disease. However, significant limitations restrict the quality and interpretability of these findings, including a paucity of controlled data, small sample sizes, and inconsistent reporting of dietary adherence.

CONCLUSIONS

Although initial findings appear promising, it remains unclear whether plant-based diets are an effective adjunct or sole therapy for managing inflammatory bowel disease. Future investigators should aim to conduct methodologically rigorous interventional trials with appropriate control data and consistent and meaningful outcome reporting.

Crohn's Disease Exclusion Diet for the Treatment of Crohn's Disease: Real-World Experience from a Tertiary Center

The Crohn's Disease (CD) exclusion diet (CDED) has been shown to induce remission in pediatric and adult patients with CD. In this retrospective cohort study, we describe our real-world experience with the CDED at the inflammatory bowel disease (IBD) unit of the Tel Aviv Medical Center between 2018-2021. CD patients with multiple clinical presentations and disease phenotypes who initiated the diet were included. Indications for treatment, medical and nutritional data were collected from dietician clinic visits and medical records. Clinical and biomarker responses were determined. The CDED was recommended to 220 CD patients. Seventy-two patients were included in the analysis for a clinically active disease (n = 48) or for remission maintenance (n = 24). Among patients with a clinically active disease, 62.5% of patients achieved clinical remission at week 6 and at week 12. A positive association between high adherence to the CDED and clinical remission at week 12 was observed (adjusted OR = 7.6, 95% CI 1.07-55.2, p = 0.043). Among patients treated for remission maintenance, remission at week 12 was maintained among 83.3% of patients. We conclude that the CDED may be a promising intervention for multiple CD presentations and indications. These findings should be further validated in larger, prospective, controlled studies.

ESPEN guideline on Clinical Nutrition in inflammatory bowel disease

The present guideline is an update and extension of the ESPEN scientific guideline on Clinical Nutrition in Inflammatory Bowel Disease published first in 2017. The guideline has been rearranged according to the ESPEN practical guideline on Clinical Nutrition in Inflammatory Bowel Disease published in 2020. All recommendations have been checked and, if needed, revised based on new literature, before they underwent the ESPEN consensus procedure. Moreover, a new chapter on microbiota modulation as a new option in IBD treatment has been added. The number of recommendations has been increased to 71 recommendations in the guideline update. The guideline is aimed at professionals working in clinical practice, either in hospitals or in outpatient medicine, and treating patients with IBD. General aspects of care in patients with IBD, and specific aspects during active disease and in remission are addressed. All recommendations are equipped with evidence grades, consensus rates, short commentaries and links to cited literature.

Holistic healthcare in inflammatory bowel disease: time for patient-centric approaches?

Inflammatory bowel disease (IBD) is an emerging global disease characterised by chronic inflammation of the gastrointestinal tract. However, IBD is also manifested by several extraintestinal symptoms which, along with the intestinal symptoms, impact on the mental and emotional well-being of patients. Despite therapeutic advancements, only one-third of the diagnosed patients receiving approved medical treatments achieve short-term to medium-term remission. Consequently, patients who do not get successfully treated might resort to using complementary and alternative approaches to manage their symptoms, with or without consulting their treating clinician. Despite their possible potential, such approaches have various risks stemming from unknown adverse reactions and possible interference with medically approved therapies. In this study, we present the results of a well-performed literature review where we included randomised clinical trials which have assessed the efficacy of complementary approaches and dietary therapy on at least one of the following four outcomes: clinical remission, endoscopic remission, modulation of molecular biomarkers or quality of life metrics. By pointing out intraoutcome and interoutcome concordance, we identified possible candidates for clinical adoption and further study in larger randomised clinical trials covering the broad spectrum of IBD heterogeneity. We finally proposed a patient-centric clinical care model and a series of recommendations for stakeholders, with special attention to complementary approaches and dietary strategies, aimed at achieving holistic remission.

Diet fuelling inflammatory bowel diseases: preclinical and clinical concepts

The diet and gut microbiota have been extensively interrogated as a fuel for gut inflammation in inflammatory bowel diseases (IBDs) in the last few years. Here, we review how specific nutrients, typically enriched in a Western diet, instigate or deteriorate experimental gut inflammation in a genetically susceptible host and we discuss microbiota-dependent and independent mechanisms. We depict the study landscape of nutritional trials in paediatric and adult IBD and delineate common grounds for dietary advice. Conclusively, the diet reflects a critical rheostat of microbial dysbiosis and gut inflammation in IBD. Dietary restriction by exclusive enteral nutrition, with or without a specific exclusion diet, is effectively treating paediatric Crohn's disease, while adult IBD trials are less conclusive. Insights into molecular mechanisms of nutritional therapy will change the perception of IBD and will allow us to enter the era of precision nutrition. To achieve this, we discuss the need for carefully designed nutritional trials with scientific rigour comparable to medical trials, which also requires action from stake holders. Establishing evidence-based dietary therapy for IBD does not only hold promise to avoid long-term immunosuppression, but to provide a widely accessible therapy at low cost. Identification of dietary culprits disturbing gut health also bears the potential to prevent IBD and allows informed decision making in food politics.

Exclusive Enteral Nutrition Exerts Anti-Inflammatory Effects through Modulating Microbiota, Bile Acid Metabolism, and Immune Activities

Exclusive enteral nutrition (EEN) can induce remission in patients with pediatric Crohn’s disease (CD). This study aims to depict EEN’s modification of bile acid (BA) metabolism in pediatric CD and explores the effect of the EEN-enriched BA in inhibiting the inflammatory response. The twelve enrolled pediatric CD patients showed BA dysmetabolism, represented by decreased levels of fecal secondary and unconjugated BAs as determined by UPLC–TQMS, which were accompanied by gut microbiota dysbiosis and reduced BA-metabolizing bacteria including Eubacterium and Ruminococcus genera, assessed by shotgun metagenomic sequencing. EEN treatment induced remission in these patients at eight weeks, and nine patients remained in stable remission for longer than 48 weeks. EEN improved BA dysmetabolism, with some enriched BAs, including hyocholic acid (HCA), α-muricholic acid (αMCA), strongly associated with decreased severity of CD symptoms. These BAs were significantly correlated with the increased abundance of certain bacteria, including Clostridium innocuum and Hungatella hathewayi, which express 3β-hydroxysteroid dehydrogenase and 5β-reductase. HCA could suppress TNF-α production by CD4+ T cells in the peripheral blood mononuclear cells (PBMCs) of CD patients. Moreover, intraperitoneal injection of HCA could attenuate dextran sulfate sodium (DSS)-induced mouse colitis. Our data suggests that BA modification may contribute to the EEN-induced remission of pediatric CD.

Review article: the future of microbiome-based therapeutics

BACKGROUND

From consumption of fermented foods and probiotics to emerging applications of faecal microbiota transplantation, the health benefit of manipulating the human microbiota has been exploited for millennia. Despite this history, recent technological advances are unlocking the capacity for targeted microbial manipulation as a novel therapeutic.

AIM

This review summarises the current developments in microbiome-based medicines and provides insight into the next steps required for therapeutic development.

METHODS

Here we review current and emerging approaches and assess the capabilities and weaknesses of these technologies to provide safe and effective clinical interventions. Key literature was identified through Pubmed searches with the following key words, 'microbiome', 'microbiome biomarkers', 'probiotics', 'prebiotics', 'synbiotics', 'faecal microbiota transplant', 'live biotherapeutics', 'microbiome mimetics' and 'postbiotics'.

RESULTS

Improved understanding of the human microbiome and recent technological advances provide an opportunity to develop a new generation of therapies. These therapies will range from dietary interventions, prebiotic supplementations, single probiotic bacterial strains, human donor-derived faecal microbiota transplants, rationally selected combinations of bacterial strains as live biotherapeutics, and the beneficial products or effects produced by bacterial strains, termed microbiome mimetics.

CONCLUSIONS

Although methods to identify and refine these therapeutics are continually advancing, the rapid emergence of these new approaches necessitates accepted technological and ethical frameworks for measurement, testing, laboratory practices and clinical translation.

Diet as a treatment for inflammatory bowel disease: is it ready for prime time?

PURPOSE OF REVIEW

Diet remains an important topic for patients with inflammatory bowel disease (IBD), yet few guidelines for dietary recommendations exist. There is a growing interest in the use of diet as treatment or adjuvant therapy for both ulcerative colitis and Crohn's disease. Here, we highlight the latest evidence on the use of diet for treatment of symptoms, active disease and maintenance of remission in ulcerative colitis and Crohn's disease.

RECENT FINDINGS

The Crohn's Disease Exclusion Diet (CDED) and the Specific Carbohydrate Diet (SCD) are studied diets that have gained popularity, but there is growing interest in the use and efficacy of less restrictive diets such as the Mediterranean diet. Recent data suggest healthful dietary patterns alone, with an emphasis on whole foods that are high in vegetable fibre and that promote less consumption of ultra-processed foods may also help achieve remission in patients with ulcerative colitis and Crohn's disease.

SUMMARY

In this review, we summarize the literature on diet as treatment for IBD. We highlight the latest clinical dietary studies, randomized clinical trials, as well as new and emerging diets for the treatment of IBD.

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.

Exclusive Enteral Nutrition in Adult Crohn's Disease: an Overview of Clinical Practice and Perceived Barriers

Recently, the role of nutrition in the management of Crohn's disease (CD) is of increasing interest and the exploration of novel nutritional interventions to improve long-term management of the disease is challenging. So far, the majority of the studies on the role of exclusive enteral nutrition (EEN) in CD are conducted in the pediatric population and have highlighted the efficacy of EEN for achieving mucosal healing. This implicates that a similar approach would be beneficial in adult patients. However, the evidence for EEN in adults is heterogeneous, with meta-analyses reporting it as inferior to steroids while growing data demonstrate improvement in complicated CD. Currently, EEN is less used in adult patients with IBD. Indeed, the lack of palatability of enteral formula leads to difficulties in acceptance and compliance. The search for more tolerable and still effective diets has become an intense area of research aiming to explore the potential role of diet to control inflammation in patients with CD. Thus, this narrative review provides the state-of-the-art on the use of EEN treatment in CD and highlights the perceived barriers to its implementation in adult CD patients.

Nutritional Therapies and Their Influence on the Intestinal Microbiome in Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, autoimmune disorder of the gastrointestinal tract with numerous genetic and environmental risk factors. Patients with Crohn’s disease (CD) or ulcerative colitis (UC) often demonstrate marked disruptions of their gut microbiome. The intestinal microbiota is strongly influenced by diet. The association between the increasing incidence of IBD worldwide and increased consumption of a westernized diet suggests host nutrition may influence the progression or treatment of IBD via the microbiome. Several nutritional therapies have been studied for the treatment of CD and UC. While their mechanisms of action are only partially understood, existing studies do suggest that diet-driven changes in microbial composition and function underlie the diverse mechanisms of nutritional therapy. Despite existing therapies for IBD focusing heavily on immune suppression, nutrition is an important treatment option due to its superior safety profile, potentially low cost, and benefits for growth and development. These benefits are increasingly important to patients. In this review, we will describe the clinical efficacy of the different nutritional therapies that have been described for the treatment of CD and UC. We will also describe the effects of each nutritional therapy on the gut microbiome and summarize the strength of the literature with recommendations for the practicing clinician.

Current Use of EEN in Pre-Operative Optimisation in Crohn's Disease

Despite the increasing array of medications available for the treatment of Crohn's disease and a focus on mucosal healing, approximately 35% of patients with Crohn's disease undergo bowel surgery at some stage. The importance of nutritional optimisation before Crohn's surgery is well-highlighted by surgical, nutritional, and gastroenterological societies with the aim of reducing complications and enhancing recovery. Surgical procedures are frequently undertaken when other treatment options have been unsuccessful, and, thus, patients may have lost weight and/or required steroids, and are therefore at higher risk of post-operative complications. EEN is used extensively in the paediatric population to induce remission, but is not routinely used in the induction of remission of adult Crohn's disease or in pre-operative optimisation. Large prospective studies regarding the role of pre-operative EEN are lacking. In this review, we evaluate the current literature on the use of EEN in pre-operative settings and its impact on patient outcomes.