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

Interaction between diet and genetics in patients with inflammatory bowel disease

In this editorial, we comment on the article by Marangoni et al, published in the recent issue of the World Journal of Gastroenterology 2023; 29: 5618-5629, about "Diet as an epigenetic factor in inflammatory bowel disease". The authors emphasized the role of diet, especially the interaction with genetics, in promoting the inflammatory process in inflammatory bowel disease (IBD) patients, focusing on DNA methylation, histone modifications, and the influence of microRNAs. In this editorial, we explore the interaction between genetics, gut microbiota, and diet, in an only way. Furthermore, we provided dietary recommendations for patients with IBD. The Western diet, characterized by a low fiber content and deficiency the micronutrients, impacts short-chain fatty acids production and may be related to the pathogenesis of IBD. On the other hand, the consumption of the Mediterranean diet and dietary fibers are associated with reduced risk of IBD flares, particularly in Crohn's disease (CD) patients. According to the dietary guidance from the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD), the regular consumption of fruits and vegetables while reducing the consumption of saturated, trans, dairy fat, additives, processed foods rich in maltodextrins, and artificial sweeteners containing sucralose or saccharine is recommended to CD patients. For patients with ulcerative colitis, the IOIBD recommends the increased intake of natural sources of omega-3 fatty acids and follows the same restrictive recommendations aimed at CD patients, with the possible inclusion of red meats. In conclusion, IBD is a complex and heterogeneous disease, and future studies are needed to elucidate the influence of epigenetics on diet and microbiota in IBD patients.

A Whole Food Plant-Based Approach to Ulcerative Colitis; A Case Series

Inflammatory bowel disease (IBD) is a relapsing and remitting condition that requires continuous treatment to reduce the risk of relapse. Alongside genetic factors, diet and lifestyle factors are heavily implicated in the pathogenesis of the disease, with diets high in meat and ultra-processed foods and low in fibre-rich plant foods thought to be central to the disease process. There is considerable interest in using dietary interventions to prevent, treat and IBD, with the hope that this can limit and, in some cases, even eliminate the use of pharmaceutical interventions. A whole food plant-based diet (WFPBD) is an attractive option given its emphasis on foods that promote gut health and reduce inflammation and the avoidance of foods that are associated with dysbiosis and inflammation. Here we describe 3 case histories of patients with ulcerative colitis and the successful use of a WFPBD for remission induction and maintenance with over 2 years of follow-up.

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.

Targeting the aryl hydrocarbon receptor by gut phenolic metabolites: A strategy towards gut inflammation

The Aryl Hydrocarbon Receptor (AHR) is a ligand-dependent transcription factor able to control complex transcriptional processes in several cell types, which has been correlated with various diseases, including inflammatory bowel diseases (IBD). Numerous studies have described different compounds as ligands of this receptor, like xenobiotics, natural compounds, and several host-derived metabolites. Dietary (poly)phenols have been studied regarding their pleiotropic activities (e.g., neuroprotective and anti-inflammatory), but their AHR modulatory capabilities have also been considered. However, dietary (poly)phenols are submitted to extensive metabolism in the gut (e.g., gut microbiota). Thus, the resulting gut phenolic metabolites could be key players modulating AHR since they are the ones that reach the cells and may exert effects on the AHR throughout the gut and other organs. This review aims at a comprehensive search for the most abundant gut phenolic metabolites detected and quantified in humans to understand how many have been described as AHR modulators and what could be their impact on inflammatory gut processes. Even though several phenolic compounds have been studied regarding their anti-inflammatory capacities, only 1 gut phenolic metabolite, described as AHR modulator, has been evaluated on intestinal inflammatory models. Searching for AHR ligands could be a novel strategy against IBD.

Role of an Exclusion Diet (Reduced Disaccharides, Saturated Fats, Emulsifiers, Red and Ultraprocessed Meats) in Maintaining the Remission of Chronic Inflammatory Bowel Diseases in Adults

Background and Objectives: Inflammatory bowel diseases are a main focus in current research, with diet being an emerging therapeutic line due to its links in both onset and progression. A Western-style diet high in processed foods, food additives, red meat, and animal fat has been linked to a higher risk of developing IBD. The aim of this study was to establish an association between an anti-inflammatory exclusion diet and maintenance of remission in IBD. Also, we assessed the efficacy and safety of this diet compared to a non-dietary group and the possible therapeutic effect of this diet in the maintenance of IBD remission. Materials and Methods: A total of 160 patients with IBD were screened for inclusion, but 21 did not met the inclusion criteria. Thus, 139 patients were assigned to either an exclusion diet or a regular diet according to their choice. Results: Clinical remission after six months was maintained in the exclusion diet arm (100%). In the control arm, four patients had clinically active disease (one patient with UC and three with CD), and 90 patients maintained the clinical remission state (95.7%) (p-value = 0.157). Regarding biochemical markers, ESR at baseline was higher in the exclusion diet arm: 29 (5-62) versus in the control arm 16 (4-48) (p-value = 0.019), but six months after, the groups were similar (p-value = 0.440). Conclusions: Patients who followed an exclusion diet maintained clinical remission more frequently. However, the threshold for statistical significance was not achieved. There was also a trend of improvement in inflammation tests in the intervention group.

Current Nutritional Therapies in Inflammatory Bowel Disease: Improving Clinical Remission Rates and Sustainability of Long-Term Dietary Therapies

Inflammatory Bowel Disease (IBD) includes a spectrum of chronic immune-mediated intestinal diseases thought to be related to the complex interaction between the host immune system and the intestinal microbiome. Research supports the use of nutritional therapy in IBD; however, it is not routinely used in clinical practice. This literature review seeks to advance the understanding of diet and its effect in IBD with a focus on both Crohn's Disease (CD) and Ulcerative Colitis (UC). The contribution of diet to the development and treatment of IBD cannot be overstated. In both pediatric as well as adult IBD, nutritional interventions have been shown to improve clinical symptoms as well as inflammatory burden. The impact of dietary intervention is best exemplified through the use of Exclusive Enteral Nutrition (EEN) in CD. EEN and clinical research on exclusionary whole food diets-Crohn's Disease Exclusion Diet (CDED), Specific Carbohydrate Diet (SCD), low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet, and Mediterranean Diet-are discussed within this review. Current clinical literature supports the elimination of detrimental components and the incorporation of low processed whole foods in the diet. Additional prospective and longitudinal dietary studies on sustainable and long-term dietary options, along with a deeper understanding of the mechanism, are needed to further advance the role of nutritional interventions in IBD.