Low FODMAP Diet for Functional Gastrointestinal Symptoms in Quiescent Inflammatory Bowel Disease: A Systematic Review of Randomized Controlled Trials

The low-FODMAP diet

In this article we present a protocol for the use of the low-FODMAP diet in paediatric patients and review of the current evidence on its efficacy. These short-chain carbohydrates, which can be fermented by the intestinal microbiota, are found in a wide variety of foods, mainly of plant origin. The low-FODMAP diet is a therapeutic tool used for the management of gastrointestinal disorders such as irritable bowel syndrome. The sources we used were PubMed, Web of Science, Google Scholar and institutional websites. Following consumption of FODMAP-rich foods, a series of end products are generated that are not absorbed, giving rise to symptoms. Before starting a low-FODMAP diet, it is important to carry out a diagnostic evaluation including any applicable tests. Treatment is structured in 3 phases: elimination, reintroduction and personalization phase. In the first phase, FODMAP-rich foods are eliminated for 2-3 weeks. In the second phase, lasting 8 weeks, FODMAP-rich foods are gradually reintroduced. The last phase consists in customizing the diet according to individual tolerance. This article details which foods contain FODMAPs and possible substitutes. In addition, specific food diary/intake tracking and educational materials are provided in a series of appendices to facilitate adherence to the diet. Although most studies have been conducted in adults, there is also some evidence on the beneficial effects in the paediatric age group, with a reduction of symptoms, especially in patients with functional gastrointestinal disorders. Nevertheless, more research is required on the subject.

Survey of dietary beliefs and habits of inflammatory bowel disease patients

BACKGROUND & AIMS

It is presumed that diet plays a role in the prevention and pathogenesis of inflammatory bowel disease (IBD). Patients with Crohn's disease (CD) and ulcerative colitis (UC) often report a link between their disease and diet. However, studies evaluating patient perceptions on diet in IBD are lacking. This study aimed to assess patient beliefs on the role of diet in IBD and the adequacy of dietary advice they received.

METHODS

A self-administered questionnaire was offered to consecutive patients attending two IBD centers in Switzerland. Data were collected regarding patient dietary beliefs and behaviors and whether they received medical advice on their diet.

RESULTS

Of 210 questionnaires distributed, 171 were completed. Participants were mainly female (53%), young (median age 38 years) with either CD (66%) or UC (34%). Most patients believed that diet plays a role in their disease (74%), whereas only 15% believed that diet could be the trigger of their disease. Since their IBD diagnosis, more than half of patients (56%) modified their diet, and 39% did not receive dietary advice from their physicians or a dietician. Most patients (91-95%) ingested gluten, lactose, red and white meat. 20% of patients practiced intermittent fasting and only a minority had previously tried a low-FODMAP (9%) diet or probiotics supplementation (16%).

CONCLUSION

The majority of IBD patients believe that diet plays a role in their disease but have never received dietary advice from their doctor or a dietician. This highlights a need for more information for IBD patients on dietary advice from the medical profession.

A primer on common supplements and dietary measures used by patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic disease of the intestines. The pathophysiology of IBD, namely Crohn's disease and ulcerative colitis, is a complex interplay between environmental, genetic, and immune factors. Physicians and patients often seek complementary and alternative medicines (CAMs) as primary and supplementary treatment modalities. CAMs in IBD span a wide range of plants, herbs, pre/probiotics, and include formulations, such as cannabis, curcumin, fish oil, and De Simone Formulation. Dietary measures are also used to improve symptoms by attempting to target trigger foods and reducing inflammation. Examples include the specific carbohydrate diet, the Mediterranean diet, and a diet low in fermentable oligo-, di- and monosaccharides as well as polyols (FODMAP). We examine and review the most common complementary supplements and diets used by patients with IBD.

Gastrointestinal tract involvement in systemic sclerosis: The roles of diet and the microbiome

BACKGROUND

Alterations in gastrointestinal (GI) microbial composition have been reported in patients with systemic sclerosis (SSc). However, it is unclear to what degree these alterations and/or dietary changes contribute to the SSc-GI phenotype.

OBJECTIVES

Our study aimed to 1) evaluate the relationship between GI microbial composition and SSc-GI symptoms, and 2) compare GI symptoms and GI microbial composition between SSc patients adhering to a low versus non-low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet.

METHODS

Adult SSc patients were consecutively recruited to provide stool specimens for bacterial 16S rRNA gene sequencing. Patients completed the UCLA Scleroderma Clinical Trial Consortium Gastrointestinal Tract Instrument (GIT 2.0) and the Diet History Questionnaire (DHQ) II and were classified as adhering to a low or non-low FODMAP diet. GI microbial differences were assessed using three metrics of alpha diversity (species richness, evenness, and phylogenetic diversity), as well as beta diversity (overall microbial composition). Differential abundance analysis was performed to identify specific genera associated with SSc-GI phenotype and low versus non-low FODMAP diet.

RESULTS

Of the 66 total SSc patients included, the majority were women (n = 56) with a mean disease duration of 9.6 years. Thirty-five participants completed the DHQ II. Increased severity of GI symptoms (total GIT 2.0 score) was associated with decreased species diversity and differences in GI microbial composition. Specifically, pathobiont genera (e.g., Klebsiella and Enterococcus) were significantly more abundant in patients with increased GI symptom severity. When comparing low (N = 19) versus non-low (N = 16) FODMAP groups, there were no significant differences in GI symptom severity or in alpha and beta diversity. Compared with the low FODMAP group, the non-low FODMAP group had greater abundance of the pathobiont Enterococcus.

CONCLUSION

SSc patients reporting more severe GI symptoms exhibited GI microbial dysbiosis characterized by less species diversity and alterations in microbial composition. A low FODMAP diet was not associated with significant alterations in GI microbial composition or reduced SSc-GI symptoms; however, randomized controlled trials are needed to evaluate the impact of specific diets on GI symptoms in SSc.

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.

Unfermented β-fructan Fibers Fuel Inflammation in Select Inflammatory Bowel Disease Patients

BACKGROUND & AIMS

Inflammatory bowel diseases (IBD) are affected by dietary factors, including nondigestible carbohydrates (fibers), which are fermented by colonic microbes. Fibers are overall beneficial, but not all fibers are alike, and some patients with IBD report intolerance to fiber consumption. Given reproducible evidence of reduced fiber-fermenting microbes in patients with IBD, we hypothesized that fibers remain intact in select patients with reduced fiber-fermenting microbes and can then bind host cell receptors, subsequently promoting gut inflammation.

METHODS

Colonic biopsies cultured ex vivo and cell lines in vitro were incubated with oligofructose (5 g/L), or fermentation supernatants (24-hour anaerobic fermentation) and immune responses (cytokine secretion [enzyme-linked immunosorbent assay/meso scale discovery] and expression [quantitative polymerase chain reaction]) were assessed. Influence of microbiota in mediating host response was examined and taxonomic classification of microbiota was conducted with Kraken2 and metabolic profiling by HUMAnN2, using R software.

RESULTS

Unfermented dietary β-fructan fibers induced proinflammatory cytokines in a subset of IBD intestinal biopsies cultured ex vivo, and immune cells (including peripheral blood mononuclear cells). Results were validated in an adult IBD randomized controlled trial examining β-fructan supplementation. The proinflammatory response to intact β-fructan required activation of the NLRP3 and TLR2 pathways. Fermentation of β-fructans by human gut whole microbiota cultures reduced the proinflammatory response, but only when microbes were collected from patients without IBD or patients with inactive IBD. Fiber-induced immune responses correlated with microbe functions, luminal metabolites, and dietary fiber avoidance.

CONCLUSION

Although fibers are typically beneficial in individuals with normal microbial fermentative potential, some dietary fibers have detrimental effects in select patients with active IBD who lack fermentative microbe activities. The study is publicly accessible at the U.S. National Institutes of Health database (clinicaltrials.gov identification number NCT02865707).

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.

Food as Treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD), namely, Crohn's disease (CD) and ulcerative colitis (UC), are lifelong and incurable chronic inflammatory diseases affecting 6.8 million people worldwide. By 2030, the prevalence of IBD is estimated to reach 1% of the population in Western countries, and thus there is an urgent need to develop effective therapies to reduce the burden of this disease. Microbiome dysbiosis is at the heart of the IBD pathophysiology, and current research and development efforts for IBD treatments have been focused on gut microbiome regulation. Diet can shape the intestinal microbiome. Diet is also preferred over medication, is safe, and has been proven to be an effective strategy for the management of IBD. Therefore, although often overlooked, dietary interventions targeting the microbiome represent ideal treatments for IBD. Here, I summarize the latest research on diet as a treatment for IBD from infancy to adulthood, compile evidence of the mechanisms of action behind diet as treatment, and, lastly, provide insights into future research focusing on culturally tailored diets for ethnic minority groups with increased incidence of IBD yet underrepresented in nutrition research.

A Low-FODMAP Diet Provides Benefits for Functional Gastrointestinal Symptoms but Not for Improving Stool Consistency and Mucosal Inflammation in IBD: A Systematic Review and Meta-Analysis

Background: A low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (LFD) is claimed to improve functional gastrointestinal symptoms (FGSs). However, the role of LFD in inflammatory bowel disease (IBD) patients with FGSs remains unclear. Objective: To systematically assess the efficacy of LFD in IBD patients with FGSs. Methods: Six databases were searched from inception to 1 January 2022. Data were synthesized as the relative risk of symptoms improvement and normal stool consistency, mean difference of Bristol Stool Form Scale (BSFS), Short IBD Questionnaire (SIBDQ), IBS Quality of Life (IBS-QoL), Harvey-Bradshaw index (HBi), Mayo score, and fecal calprotectin (FC). Risk of bias was assessed based on study types. A funnel plot and Egger’s test were used to analyze publication bias. Results: This review screened and included nine eligible studies, including four randomized controlled trials (RCTs) and five before–after studies, involving a total of 446 participants (351 patients with LFD vs. 95 controls). LFD alleviated overall FGSs (RR: 0.47, 95% CI: 0.33–0.66, p = 0.0000) and obtained higher SIBDQ scores (MD = 11.24, 95% CI 6.61 to 15.87, p = 0.0000) and lower HBi score of Crohn’s disease (MD = −1.09, 95% CI −1.77 to −0.42, p = 0.002). However, there were no statistically significant differences in normal stool consistency, BSFS, IBS-QoL, Mayo score of ulcerative colitis, and FC. No publication bias was found. Conclusions: LFD provides a benefit in FGSs and QoL but not for improving stool consistency and mucosal inflammation in IBD patients. Further well-designed RCTs are needed to develop the optimal LFD strategy for IBD.

FODMAPs, inflammatory bowel disease and gut microbiota: updated overview on the current evidence

PURPOSE

Based on the fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) hypothesis, the low-FODMAP diet has been suggested as a potential therapeutic approach for inflammatory bowel disease (IBD) with promising results on disease management. However, this diet implies a specific broad food restriction, which potentially increases the risk of nutritional deficiencies and may aggravate gut microbiota dysbiosis of IBD patients. The aim of the present study is to review the effect of individual FODMAPs on the human gut microbiota. In addition, this narrative review provides an updated overview of the use of the low-FODMAP diet in IBD, namely the implementation, advantages, limitations, and the impact on the gut microbiota.

METHODS

The literature search strategy was applied to PubMed and Web of Science using relevant keywords, IBD, FODMAPs, Fructose, Lactose, Polyols, FOS, GOS, low-FODMAP diet and gut microbiota.

RESULTS

Current data suggest that the low-FODMAP diet may effectively improve clinical outcomes in the management of IBD and ensure better quality of life for IBD patients. However, there is evidence highlighting some issues of concern, particularly the adequacy of the diet and the impact on the gut microbiota. The various FODMAP types differently modulate the gut microbiota.

CONCLUSION

IBD management should be achieved with the least possible dietary restriction to avoid detrimental consequences, particularly on nutritional adequacy and gut microbiota. Thus, it is important to individualize and monitor the nutrition intervention. Further studies are required to better characterize the relationship between diet, the gut microbiota, and IBD to support the generalization of this approach for clinical practice in IBD therapy and management.

Nutrition in Ankylosing Spondyloarthropathies and Related Immune-Mediated Disorders

Recent research on the pathogenesis of spondyloarthritis and related immune-mediated diseases associated with human leukocyte antigen class I molecule B27 (HLA-B27) has led to significant progress in terms of management and prognosis, with multiple treatments being constantly evaluated and implemented. Correlations between the genetic background of spondyloarthritis and inflammatory bowel diseases and the inflammatory processes involving gut microbiota have been established. This knowledge has allowed progress in pharmacological therapy. The role of diet in the pathogenesis and treatment of diseases pertaining to the HLA-B27 spectrum is of great significance, considering possible future applications in individualized medicine. Diet impacts the composition of gut microbiota, representing a substrate for the synthesis of metabolites affecting the mucosal immune system. Certain pro-inflammatory mediators, such as emulsifiers and microparticles, induce a more profound cytokine response, promoting inflammation. Numerous diets, including the low-starch diet, the Mediterranean diet, diets with low contents of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (low-FODMAP diets), gluten-free diets and fasting, have been analysed and correlated with patients’ symptomatology and dietary adherence. The aim of this review is to provide an extensive perspective on the diets available to patients with spondyloarthritis and related immune-mediated disorders.

Gut microbiota in inflammatory bowel disease: a target for therapy not to be missed

In the last years, the gut microbiota achieved great importance, since several studies demonstrated its correlation with the immune system and with the maintenance of intestinal homeostasis, as well as with the regulation of the integrity of the epithelium and the intestinal motility. An imbalance in microbial species promotes a dysbiosis, which has been associated with chronic diseases such as metabolic syndrome, inflammatory diseases, and some behavior disorders. The association with gut microbiota and dysbiosis has been demonstrated mostly in inflammatory bowel disease (IBD). Several studies investigated the application of antibiotics, prebiotics, probiotics, and fecal microbiota transplantation in the treatment strategies for IBD. In this review, we discuss the recent findings on the potential role of the gut microbiota manipulation, with particular attention to bacterial microbiota, which could be implicated for a successful IBD therapeutic approach.

Food and Food Groups in Inflammatory Bowel Disease (IBD): The Design of the Groningen Anti-Inflammatory Diet (GrAID)

Diet plays a pivotal role in the onset and course of inflammatory bowel disease (IBD). Patients are keen to know what to eat to reduce symptoms and flares, but dietary guidelines are lacking. To advice patients, an overview of the current evidence on food (group) level is needed. This narrative review studies the effects of food (groups) on the onset and course of IBD and if not available the effects in healthy subjects or animal and in vitro IBD models. Based on this evidence the Groningen anti-inflammatory diet (GrAID) was designed and compared on food (group) level to other existing IBD diets. Although on several foods conflicting results were found, this review provides patients a good overview. Based on this evidence, the GrAID consists of lean meat, eggs, fish, plain dairy (such as milk, yoghurt, kefir and hard cheeses), fruit, vegetables, legumes, wheat, coffee, tea and honey. Red meat, other dairy products and sugar should be limited. Canned and processed foods, alcohol and sweetened beverages should be avoided. This comprehensive review focuses on anti-inflammatory properties of foods providing IBD patients with the best evidence on which foods they should eat or avoid to reduce flares. This was used to design the GrAID.

The Multifaceted Roles of Diet, Microbes, and Metabolites in Cancer

Many studies performed to date have implicated select microbes and dietary factors in a variety of cancers, yet the complexity of both these diseases and the relationship between these factors has limited the ability to translate findings into therapies and preventative guidelines. Here we begin by discussing recently published studies relating to dietary factors, such as vitamins and chemical compounds used as ingredients, and their contribution to cancer development. We further review recent studies, which display evidence of the microbial-diet interaction in the context of cancer. The field continues to advance our understanding of the development of select cancers and how dietary factors are related to the development, prevention, and treatment of these cancers. Finally, we highlight the science available in the discussion of common misconceptions with regards to cancer and diet. We conclude this review with thoughts on where we believe future research should focus in order to provide the greatest impact towards human health and preventative medicine.