Modified Crohn's disease exclusion diet is equally effective as exclusive enteral nutrition: Real-world data

The Crohn's Disease Exclusion Diet: A Comprehensive Review of Evidence, Implementation Strategies, Practical Guidance, and Future Directions

Dietary therapy is increasingly recognized for the management of Crohn's disease (CD) over recent years, including the use of exclusive enteral nutrition (EEN) as first-line therapy for pediatric CD according to current guidelines. The Crohn's disease exclusion diet (CDED) is a whole-food diet designed to reduce exposure to dietary components that are potentially pro-inflammatory, mediated by negative effects on the gut microbiota, immune response, and the intestinal barrier. The CDED has emerged as a valid alternative to EEN with cumulative evidence, including randomized controlled trials, supporting use for induction of remission and possibly maintenance in children and adults. We gathered a group of multidisciplinary experts, including pediatric and adult gastroenterologists, inflammatory bowel diseases (IBD) expert dietitians, and a psychologist to discuss the evidence, identify gaps, and provide insights into improving the use of CDED based on a comprehensive review of CDED literature and professional experience. This article reviews the management of CDED in both children and adults, long-term aspects of CDED, indications and contraindications, selecting the best candidates, identifying challenges with CDED, globalization, the role of the multidisciplinary team, especially of dietitian, and future directions. We concluded that CDED is an established dietary therapy that could serve as an alternative to EEN in many pediatric and adult cases, especially with mild to moderate disease. In severe disease, complicated phenotypes, or with extraintestinal involvement, CDED should be considered on a case-by-case basis, according to physician and dietitians' discretion. More studies are warranted to assess the efficacy of CDED in different scenarios.

Cultural Perspectives on the Efficacy and Adoption of the Crohn's Disease Exclusion Diet across Diverse Ethnicities: A Case-Based Overview

BACKGROUND

The Crohn's Disease Exclusion Diet (CDED) is a whole-foods regimen that has demonstrated efficacy in inducing remission among children and adults with mild-to-moderate disease. While initial studies predominantly originated from Israel, recent years have witnessed the expansion of experiences to diverse cultures, culminating in the recognition of CDED in the latest ESPEN guidelines. However, implementing dietary therapy poses significant challenges across various cultures, necessitating adaptations.

AIM AND METHODS

This case-based study aims to present the collective experience from different cultures, shedding light on the encountered challenges and the corresponding solutions devised to surmount them by convening healthcare providers (dietitians and physicians across six countries and eight cultural settings) with extensive experience in utilizing the CDED.

RESULTS AND CONCLUSIONS

Our findings underscore the efficacy of CDED across diverse cultural contexts and emphasize the pivotal role of dietitians in tailoring the diet to accommodate patients' cultural behaviors and traditions. We highlight challenges encountered and delineate strategies for overcoming them by customizing the diet and offering tailored guidance. Additionally, we provide insights into implementing CDED in various regions through adjusted recipes and personalized counseling from dietitians. This study contributes to the growing body of literature on CDED, and offers practical guidance for its effective adoption in diverse cultural settings.

A real-life pediatric experience of Crohn's disease exclusion diet at disease onset and in refractory patients

OBJECTIVES

We aimed to appraise the real-life efficacy of Crohn's disease exclusion diet (CDED) coupled with partial enteral nutrition (PEN) in inducing clinical and biochemical remission at disease onset and in patients with loss of response to biologics and immunomodulators.

METHODS

We retrospectively gathered data of patients aged less than 18 years of age with a diagnosis of Crohn's disease (CD), who received CDED coupled with PEN at a tertiary level pediatric inflammatory bowel disease center.

RESULTS

Sixty-six patients were identified. Forty (60.6%) started CDED plus PEN at disease onset and 26 (39.4%) received CDED with PEN as add-on therapy. Forty-six (69.7%) patients achieved clinical remission (weighted Pediatric Crohn's Disease Activity Index < 12.5) at the end of phase 1, 44 (66.7%) normalized c-reactive protein levels (<0.5 mg/dL) and 18 (27.2%) patients normalized calprotectin levels (<150 µg/g). Nine of 19 (47.3%) of patients with clinically severe disease (defined by Physician Global Assessment) achieved clinical remission at the end of phase I. Patients with extraintestinal manifestations had statistically lower clinical response rates to the dietary regimen (p = 0.018). Among patients who received CDED + PEN as add-on treatment, a previous successful course of Exclusive Enteral Nutrition was associated with statistically higher clinical remission rates at Week 8 (p = 0.026). Clinical response at Week 4 was an independent predictor of clinical remission and fecal calprotectin normalization at Week 8 (p = 0.002).

CONCLUSION

CDED with PEN confirmed its efficacy in a real-life setting, proving to be effective also in refractory patients and those with severe disease. Early clinical response predicts clinical remission at the end of phase 1.

Pre- to Postbiotics: The Beneficial Roles of Pediatric Dysbiosis Associated with Inflammatory Bowel Diseases

Probiotics are "live microorganisms which, when administered in adequate amount, confer health benefits on the host". They can be found in certain foods like yogurt and kefir and in dietary supplements. The introduction of bacterial derivatives has not only contributed to disease control but has also exhibited promising outcomes, such as improved survival rates, immune enhancement, and growth promotion effects. It is interesting to note that the efficacy of probiotics goes beyond the viability of the bacteria, giving rise to concepts like paraprobiotics, non-viable forms of probiotics, and postbiotics. Paraprobiotics offer various health benefits in children with intestinal dysbiosis, contributing to improved digestive health, immune function, and overall well-being. In this review, the potential of these therapeutic applications as alternatives to pharmacological agents for treating pediatric intestinal dysbiosis will be thoroughly evaluated. This includes an analysis of their efficacy, safety, long-term benefits, and their ability to restore gut microbiota balance, improve digestive health, enhance immune function, and reduce inflammation. The aim is to determine if these non-pharmacological interventions can effectively and safely manage intestinal dysbiosis in children, reducing the need for conventional medications and their side effects.

Formula modifications to the Crohn's disease exclusion diet do not impact therapy success in paediatric Crohn's disease

OBJECTIVES

The Crohn's disease exclusion diet (CDED) + partial enteral nutrition (PEN) is an emerging diet used to induce clinical remission in children with active Crohn's disease (CD). This study aims to determine the effectiveness of using the CDED+PEN to induce clinical remission in an Australian group of children with active CD using different PEN formulas and incorporating patient dietary requirements.

METHODS

We retrospectively collected data from children (both newly diagnosed and with existing CD while on therapy) with active CD (Paediatric Crohn's Disease Activity Index [PCDAI] ≥10) and biochemical evidence of active disease (elevated C-reactive protein [CRP], erythrocyte sedimentation rate [ESR] or faecal calprotectin [FC]) who completed at least phase 1 (6 weeks) of the CDED+PEN to induce clinical remission. Data were collected at baseline, Week 6 and Week 12. The primary endpoint was clinical remission at Week 6 defined as PCDAI < 10.

RESULTS

Twenty-four children were included in phase 1 analysis (mean age 13.8 ± 3.2 years). Clinical remission at Week 6 was achieved in 17/24 (70.8%) patients. Mean PCDAI, CRP, ESR and FC decreased significantly after 6 weeks (p < 0.05). Formula type (cow's milk based, rice based, soy based) did not affect treatment efficacy. A greater than 50% decrease in FC was achieved in 14/21 (66.7%) patients who completed phase 1 and 12/14 (85.7%) patients who completed phase 2 of the CDED+PEN.

CONCLUSIONS

Formula modifications to the CDED+PEN do not impact the expected treatment efficacy in Australian children with active luminal CD.

Progress and Clinical Applications of Crohn's Disease Exclusion Diet in Crohn's Disease

Crohn's disease is a chronic intestinal inflammatory disorder of unknown etiology. Although the pharmacotherapies for Crohn's disease are constantly updating, nutritional support and adjuvant therapies have recently gained more attention. Due to advancements in clinical nutrition, various clinical nutritional therapies are used to treat Crohn's disease. Doctors treating inflammatory bowel disease can now offer several diets with more flexibility than ever. The Crohn's disease exclusion diet is a widely used diet for patients with active Crohn's disease. The Crohn's disease exclusion diet requires both exclusion and inclusion. Periodic exclusion of harmful foods and inclusion of wholesome foods gradually improves a patient's nutritional status. This article reviews the Crohn's disease exclusion diet, including its structure, mechanisms, research findings, and clinical applications.

An update on dietary therapies in paediatric Crohn's disease

PURPOSE OF REVIEW

This article provides a literature update on original articles published in the past 18 months (May 2022-November 2023) in the dietary management of paediatric Crohn's disease.

RECENT FINDINGS

There is more data to support the use of exclusive enteral nutrition in the management of active Crohn's disease in children. Several food-based dietary therapies have been proposed for the management of Crohn's disease. There is an interest in precision nutritional therapy in Crohn's disease, but current data are scarce.

SUMMARY

Exclusive enteral nutrition is an effective treatment for paediatric Crohn's disease. Predictors of response to exclusive enteral nutrition include mild disease phenotype and ileal disease involvement, although data remain inconclusive. Adherence to exclusive enteral nutrition is cornerstone to its efficacy. Treatment with exclusive enteral nutrition modifies the gut microbiome, modulates bile acid metabolism and has significant effects on host immune responses. More studies are expected in which drugs need to be combined with dietary therapies and microbial therapeutics. The efficacy of Crohn's disease exclusion diet coupled with partial enteral nutrition is supported by independent studies, but tolerance remains an issue, particularly for long-term disease management. More research is anticipated in precision nutritional therapy in paediatric Crohn's disease, but currently no recommendations can be made.

Is There Evidence of Crohn's Disease Exclusion Diet (CDED) in Remission of Active Disease in Children and Adults? A Systematic Review

Crohn's disease (CD) is an inflammatory bowel disease. Previous research has explored the impact of diet on CD, as specific dietary components can influence gut microbiota and immune responses, contributing to damage in the gastrointestinal tract. The Crohn's Disease Exclusion Diet (CDED) is based on an exclusion diet; it is a recent dietary approach that is often used alongside partial enteral nutrition (PEN) and aims to induce disease remission by excluding certain dietary components. This study assesses the current evidence for the effectiveness of the CDED + PEN in achieving remission in both children and adults with active CD. Our systematic review followed PRISMA recommendations and was registered in PROSPERO with CRD number 42022335076. The searched databases were PubMed/MEDLINE, Cochrane Library, Scopus, and Web of Science. The included studies were analyzed using Rayyan software, and the risk of bias was assessed with Cochrane RevMan 5.0 software. The primary assessed outcome was clinical remission, evaluated with validated questionnaire scores such as PCDAI, CDAI, or HBI. All analyzed papers yielded promising results. Notably, the CDED + PEN demonstrated better tolerance than exclusive enteral nutrition (EEN), resulting in higher adherence rates. Therefore, the CDED + PEN appears to be a viable alternative for induction remission in active disease for both children and adults with CD.

AGA Clinical Practice Update on Diet and Nutritional Therapies in Patients With Inflammatory Bowel Disease: Expert Review

DESCRIPTION

Diet plays a critical role in human health, but especially for patients with inflammatory bowel disease (IBD). Guidance about diet for patients with IBD are often controversial and a source of uncertainty for many physicians and patients. The role of diet has been investigated as a risk factor for IBD etiopathogenesis and as a therapy for active disease. Dietary restrictions, along with the clinical complications of IBD, can result in malnutrition, an underrecognized condition among this patient population. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update (CPU) is to provide best practice advice statements, primarily to clinical gastroenterologists, covering the topics of diet and nutritional therapies in the management of IBD, while emphasizing identification and treatment of malnutrition in these patients. We provide guidance for tailored dietary approaches during IBD remission, active disease, and intestinal failure. A healthy Mediterranean diet will benefit patients with IBD, but may require accommodations for food texture in the setting of intestinal strictures or obstructions. New data in Crohn's disease supports the use of enteral liquid nutrition to help induce remission and correct malnutrition in patients heading for surgery. Parenteral nutrition plays a critical role in patients with IBD facing acute and/or chronic intestinal failure. Registered dietitians are an essential part of the interdisciplinary team approach for optimal nutrition assessment and management in the patient population with IBD.

METHODS

This expert review was commissioned and approved by the AGA Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPU Committee and external peer review through standard procedures of Gastroenterology. The best practice advice statements were drawn from reviewing existing literature combined with expert opinion to provide practical advice on the role of diet and nutritional therapies in patients with IBD. Because this was not a systematic review, formal rating of the quality of evidence or strength of the presented considerations was not performed. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Unless there is a contraindication, all patients with IBD should be advised to follow a Mediterranean diet rich in a variety of fresh fruits and vegetables, monounsaturated fats, complex carbohydrates, and lean proteins and low in ultraprocessed foods, added sugar, and salt for their overall health and general well-being. No diet has consistently been found to decrease the rate of flares in adults with IBD. A diet low in red and processed meat may reduce ulcerative colitis flares, but has not been found to reduce relapse in Crohn's disease. BEST PRACTICE ADVICE 2: Patients with IBD who have symptomatic intestinal strictures may not tolerate fibrous, plant-based foods (ie, raw fruits and vegetables) due to their texture. An emphasis on careful chewing and cooking and processing of fruits and vegetables to a soft, less fibrinous consistency may help patients with IBD who have concomitant intestinal strictures incorporate a wider variety of plant-based foods and fiber in their diets. BEST PRACTICE ADVICE 3: Exclusive enteral nutrition using liquid nutrition formulations is an effective therapy for induction of clinical remission and endoscopic response in Crohn's disease, with stronger evidence in children than adults. Exclusive enteral nutrition may be considered as a steroid-sparing bridge therapy for patients with Crohn's disease. BEST PRACTICE ADVICE 4: Crohn's disease exclusion diet, a type of partial enteral nutrition therapy, may be an effective therapy for induction of clinical remission and endoscopic response in mild to moderate Crohn's disease of relatively short duration. BEST PRACTICE ADVICE 5: Exclusive enteral nutrition may be an effective therapy in malnourished patients before undergoing elective surgery for Crohn's disease to optimize nutritional status and reduce postoperative complications. BEST PRACTICE ADVICE 6: In patients with IBD who have an intra-abdominal abscess and/or phlegmonous inflammation that limits ability to achieve optimal nutrition via the digestive tract, short-term parenteral nutrition may be used to provide bowel rest in the preoperative phase to decrease infection and inflammation as a bridge to definitive surgical management and to optimize surgical outcomes. BEST PRACTICE ADVICE 7: We suggest the use of parenteral nutrition for high-output gastrointestinal fistula, prolonged ileus, short bowel syndrome, and for patients with IBD with severe malnutrition when oral and enteral nutrition has been trialed and failed or when enteral access is not feasible or contraindicated. BEST PRACTICE ADVICE 8: In patients with IBD and short bowel syndrome, long-term parenteral nutrition should be transitioned to customized hydration management (ie, intravenous electrolyte support and/or oral rehydration solutions) and oral intake whenever possible to decrease the risk of developing long-term complications. Treatment with glucagon-like peptide-2 agonists can facilitate this transition. BEST PRACTICE ADVICE 9: All patients with IBD warrant regular screening for malnutrition by their provider by means of assessing signs and symptoms, including unintended weight loss, edema and fluid retention, and fat and muscle mass loss. When observed, more complete evaluation for malnutrition by a registered dietitian is indicated. Serum proteins are no longer recommended for the identification and diagnosis of malnutrition due to their lack of specificity for nutritional status and high sensitivity to inflammation. BEST PRACTICE ADVICE 10: All patients with IBD should be monitored for vitamin D and iron deficiency. Patients with extensive ileal disease or prior ileal surgery (resection or ileal pouch) should be monitored for vitamin B12 deficiency. BEST PRACTICE ADVICE 11: All outpatients and inpatients with complicated IBD warrant co-management with a registered dietitian, especially those who have malnutrition, short bowel syndrome, enterocutaneous fistula, and/or are requiring more complex nutrition therapies (eg, parenteral nutrition, enteral nutrition, or exclusive enteral nutrition), or those on a Crohn's disease exclusion diet. We suggest that all newly diagnosed patients with IBD have access to a registered dietitian. BEST PRACTICE ADVICE 12: Breastfeeding is associated with a lower risk for diagnosis of IBD during childhood. A healthy, balanced, Mediterranean diet rich in a variety of fruits and vegetables and decreased intake of ultraprocessed foods have been associated with a lower risk of developing IBD.

Evolving Landscape of Paediatric Inflammatory Bowel Disease: Insights from a Decade-Long Study in North-East Slovenia on Incidence, Management, Diagnostic Delays, and Early Biologic Intervention

BACKGROUND

In the past decade, significant progress has been achieved in the care of children with inflammatory bowel disease (IBD). Our study concentrated on assessing the incidence and management of IBD in children in North-Eastern Slovenia over a 10-year period.

METHODS

Medical data from children and adolescents diagnosed with IBD in North-Eastern Slovenia (2014-2023) was analysed. Disease incidence and management of children were assessed. Findings were compared between two periods (2014-2019 and 2020-2023, coinciding with the COVID-19 pandemic).

RESULTS

87 patients (median age 15.5 year; 50.6% male) with IBD (43.7% Crohn's disease (CD)), diagnosed between 2014 and 2023 were included. Extraintestinal manifestations were more common in CD than ulcerative colitis (UC) (15.8% vs. 2.4%, p < 0.05). Median delay from symptom onset to diagnosis was 2 months, lower in UC than CD (NS). Mean annual IBD incidence per 100,000 children aged 0 to 19 years was 6.4 (95% CI 4.4-8.3), slightly lower for CD than UC (2.8/100,000 vs. 3.1/100,000). In the second period, IBD incidence significantly rose (9.1 vs. 4.6, p < 0.05). During this period, 53% of CD patients transitioned to biological treatment within three months of diagnosis.

CONCLUSION

IBD incidence rose among children in North-Eastern Slovenia over the past decade. Additionally, more children with CD underwent biological therapy in the second period.

Treatment of Active Crohn's Disease in Children Using Partial Enteral Nutrition Combined with a Modified Crohn's Disease Exclusion Diet: A Pilot Prospective Cohort Trial on Clinical and Endoscopic Outcomes

BACKGROUND

Partial enteral nutrition (PEN) coupled with the Crohn's disease (CD) exclusion diet (CDED) was shown to be effective in inducing clinical remission in paediatric CD. There are currently no robust data on the endoscopic outcomes of PEN. The aim of this study was to evaluate the clinical and endoscopic rates of remission after PEN combined with a modified CDED (mCDED) adjusted to the local cuisine in comparison with exclusive enteral nutrition (EEN) for the induction of remission.

METHODS

Between June 2017 and February 2021, a prospective cohort study on children with active CD, treated with PEN + mCDED or EEN, was performed at a single tertiary centre.

RESULTS

During the study period, 54 patients were screened and 15 were excluded according to the exclusion criteria, with six patients excluded in the first two days due to intolerance of the enteral formula. Fourteen patients were included in the PEN and 19 in the EEN group. They were assessed at Weeks 0, 1, 3 and 6, using clinical and laboratory parameters. Endoscopy was performed at Weeks 0 and 6. Clinical remission rates per protocol analysis were 84.6% in the PEN group and 81.3% in the EEN group (p = 0.99). At Week 6, an endoscopic response (a decline in the Simple Endoscopic Score for CD (SES-CD) > 50%) was observed in 84.6% of patients on PEN and in 68.8% on EEN treatment (p = 0.41). Endoscopic remission (SES-CD ≤ 2) was achieved in 53.8% of patients in the PEN group and in 50.0% in the EEN group (p = 0.99), while the mucosal healing rates (SES-CD = 0) were 38.5% with PEN and 43.8% with EEN (p = 0.99). A significant decline in the clinical and endoscopic activity scores was observed in both groups.

CONCLUSION

Our study suggests that PEN + mCDED could be effective in inducing endoscopic remission and mucosal healing in active paediatric CD patients. Here, we present an analysis of the data from our cohort of patients and our real-world experience with PEN + mCDED.

The Role of Diet in Pediatric Inflammatory Bowel Disease

The pathogenesis of inflammatory bowel disease (IBD) involves a complex interaction between genetics, immune response, and the environment. Epidemiologic associations between diet and development of IBD plus the ability of diet to modify the microbiota and modulate immune function have led to the hypothesis that diet can prevent and/or treat IBD. It is well established that the induction of remission and healing of the mucosa in Crohn's disease can be accomplished with exclusive enteral nutrition. Whole food-based alternatives such as the Crohn's disease exclusion diet have shown promising results.

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.

Efficacy of Crohn's disease exclusion diet in treatment -naïve children and children progressed on biological therapy: a retrospective chart review

BACKGROUND

Recent trials suggested that the Crohn's disease (CD) exclusion diet (CDED) plus partial enteral nutrition (PEN) is a safe and effective strategy in remission induction of paediatric-onset CD. However, real-world evidence regarding the safety and efficacy of the CDED plus PEN approach is still lacking. The present case-series study reported our experience with the outcomes of CDED plus PEN in the paediatric-onset CD at disease onset and after the loss of response to biologics.

METHODS

We conducted a retrospective chart review on children who were treated with CDED plus PEN through the period from July 2019 and December 2020. Clinical and laboratory data were retrieved and compared at baseline, 6, 12, and 24 weeks of treatment. The primary endpoint of the present study was the rate of clinical remission.

RESULTS

The present study retrieved the data from 15 patients. Of them, nine patients were treatment naïve at the time of initiation of CDED plus PEN (group A) and the remaining patients relapsed on biologics before treatment. All patients in groups A and B exhibited clinical remission in week six, which was sustained until week 12. At the end of the follow-up, the clinical remission rate was 87% and 60% in groups A and B, respectively. No side effects were observed in both groups. In group A, the faecal calprotectin (FC) and albumin improved at week six, week 12, and week 24 (p < 0.05). The erythrocyte sedimentation rate (ESR) improved significantly at week 12 (p = 0.021) and week 24 (p = 0.027). At the same time, the haemoglobin and iron levels showed significant improvement only at week 24. For group B, only FC showed numerical reductions over time that did not reach the level of statistical significance.

CONCLUSION

Treatment with CDED plus PEN was well tolerated and achieved an excellent clinical remission rate in treatment-naive patients. However, the benefit of CDED plus PEN was less in patients who initiated the strategy after losing the response to biologics.

The Role of Partial Enteral Nutrition for Induction of Remission in Crohn's Disease: A Systematic Review of Controlled Trials

Exclusive enteral nutrition (EEN) is recommended as a first-line therapy to induce remission of Crohn's disease (CD) and is considered as effective as corticosteroid treatment. However, the dietary restriction causes lack of adherence and poor tolerance to the therapy. Partial enteral nutrition (PEN), which allows for the ingestion of some food, could be a better tolerated alternative, but it is unknown whether it is as effective at inducing CD remission as EEN. The aim of this systematic review is to analyze the available evidence on PEN as a remission induction therapy in CD. A literature search was conducted using the MEDLINE (via PUBMED) and Cochrane Library databases following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Clinical trials in pediatric and adult patients were included. The risk of bias was assessed following the Cochrane Collaboration methodology. The selected studies showed variable but high response rates to PEN and EEN. Limitations regarding the wide heterogeneity between the studies included in this review should be considered. Although more studies are needed, according to our results, PEN combined with a highly restrictive diet seems to be as effective as EEN in inducing remission of CD.

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.

The Therapeutic Role of Short-Chain Fatty Acids Mediated Very Low-Calorie Ketogenic Diet-Gut Microbiota Relationships in Paediatric Inflammatory Bowel Diseases

The very low-calorie ketogenic diet (VLCKD) has been recognized as a promising dietary regimen for the treatment of several diseases. Short-chain fatty acids (SCFAs) produced by anaerobic bacterial fermentation of indigestible dietary fibre in the gut have potential value for their underlying epigenetic role in the treatment of obesity and asthma-related inflammation through mediating the relationships between VLCKD and the infant gut microbiota. However, it is still unclear how VLCKD might influence gut microbiota composition in children, and how SCFAs could play a role in the treatment of inflammatory bowel disease (IBD). To overcome this knowledge gap, this review aims to investigate the role of SCFAs as key epigenetic metabolites that mediate VLCKD-gut microbiota relationships in children, and their therapeutic potential in IBD.

Dietary Patterns and Gut Microbiota Changes in Inflammatory Bowel Disease: Current Insights and Future Challenges

Inflammatory bowel disease (IBD) is a result of a complex interplay between genes, host immune response, gut microbiota, and environmental factors. As one of the crucial environmental factors, diet plays a pivotal role in the modulation of gut microbiota community and the development of IBD. In this review, we present an overview of dietary patterns involved in the pathogenesis and management of IBD, and analyze the associated gut microbial alterations. A Westernized diet rich in protein, fats and refined carbohydrates tends to cause dysbiosis and promote IBD progression. Some dietary patterns have been found effective in obtaining IBD clinical remission, including Crohn's Disease Exclusion Diet (CDED), Mediterranean diet (MD), Anti-Inflammatory Diet (AID), the low-"Fermentable Oligo-, Di-, Mono-saccharides and Polyols" (FODMAP) diet, Specific Carbohydrate Diet (SCD), and plant-based diet, etc. Overall, many researchers have reported the role of diet in regulating gut microbiota and the IBD disease course. However, more prospective studies are required to achieve consistent and solid conclusions in the future. This review provides some recommendations for studies exploring novel and potential dietary strategies that prevent IBD.

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.