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

Diet, Food, and Nutritional Exposures and Inflammatory Bowel Disease or Progression of Disease: an Umbrella Review

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), contributes to substantial morbidity. Understanding the intricate interplay between dietary factors and the incidence and progression of IBD is essential for developing effective preventative and therapeutic strategies. This umbrella review comprehensively synthesizes evidence from systematic reviews and meta-analyses to evaluate these complex associations. Dietary factors associated with an increased incidence and/or progression of IBD include a high intake of red and processed meat, other processed foods, and refined sugars, together with a low intake of vegetables, fruits, and fiber. For most other food groups, the results are mixed or indicate no clear associations with IBD, CD, and UC. Some differences seem to exist between UC and CD and their risk factors, with increased intake of dietary fiber being inversely associated with CD incidence but not clearly associated with UC. Dietary fiber may contribute to maintaining the gut epithelial barrier and reduce inflammation, often through interactions with the gut microbiota. This seems to play an important role in inflammatory mechanisms in the gut and in IBD incidence and progression. Diets low in fermentable saccharides and polyols can alleviate symptom burden, but there are concerns regarding their impact on the gut microbiota and their nutritional adequacy. Mediterranean diets, vegetarian diets, and a diet low in grains, sugars, and lactose (specific carbohydrate diet) are also associated with lower incidence and/or progression of IBD. The associations of dietary patterns are mirrored by inflammatory biomarkers. IBD is typically treated pharmaceutically; however, many patients have a suboptimal response to medical treatments. The findings from this umbrella review could provide evidence for nutritional counseling and be a valuable addition to traditional treatment plans for IBD. This systematic review was registered at PROSPERO as CRD440252.

Dietary Behaviors and Beliefs in Patients with Inflammatory Bowel Disease

INTRODUCTION

Due to a lack of clear dietary guidelines, patients with inflammatory bowel disease (IBD) self-impose dietary restrictions based on their own nutritional experiences. The aim of this study was to investigate dietary perceptions and behavior in IBD patients.

MATERIALS AND METHODS

A total of 82 patients (48 with Crohn's disease and 34 with ulcerative colitis) participated in this prospective, questionnaire-based study. Based on a literature review, the questionnaire was developed to investigate dietary beliefs, behaviors and food exclusions during IBD relapses and remission.

RESULTS

The majority of patients (85.4%) believed that diet can be a trigger factor for IBD relapses, and 32.9% believed that diet initiates the disease. The majority of patients (81.7%) believed that they should eliminate some products from their diets. The most often-pointed-out products were spicy and fatty foods, raw fruits and vegetables, alcohol, leguminous foods, cruciferous vegetables, dairy products and milk. Most patients (75%) modified their diets after diagnosis, and 81.7% imposed food restrictions to prevent IBD relapses.

CONCLUSIONS

The majority of patients avoided certain foods during relapses as well as to maintain remission of IBD, basing this on their own beliefs, inconsistently with current scientific knowledge. Patient education should be a key determinant in IBD control.

A descriptive study of inflammatory bowel disease at an Egyptian tertiary care center

INTRODUCTION AND AIMS

Inflammatory bowel disease (IBD) is a group of chronic intestinal disorders that trigger prolonged inflammation of the digestive tract. Its incidence and prevalence appear to be increasing in the African population and in Egypt. The present study aims to highlight the pattern and management of IBD in Egyptian patients.

MATERIALS AND METHODS

Two hundred patients with IBD were assessed for ulcerative colitis (UC), through the Mayo score, and for Crohn's disease (CD), with the Crohn's disease activity index (CDAI).

RESULTS

Median patient age was 35 years, with a predominance of females. UC was more common than CD (88% and 12%, respectively) and severity was moderate, in the majority of cases. Most UC patients had left-sided lesions, whereas ileitis was the most common finding (37.5%) in the CD patients. Proctitis was the least common finding in both diseases and Crohn's fistulizing disease was detected in 4.1% of the patients. Interestingly, peripheral arthropathy was the most common extraintestinal manifestation in the IBD patients (70%) and axial arthropathy was the least common (6%). Severe ocular or mucocutaneous involvement was very rare. Finally, biologic treatment was prescribed to 15.4% of the UC patients and 20.8% of the CD patients.

CONCLUSIONS

Although the clinical presentation of IBD in Egypt is comparable to that reported worldwide, diagnoses were found to be delayed. There were fewer cases of CD than UC, but more mild-to-moderate disease severity. The surveillance of patients with IBD must continue and awareness of the disease in the Egyptian medical community needs to increase. A national registry must be established, multicenter studies need to be conducted, and molecular diagnostics is recommended.

Lower Impact of Disease on Daily Life and Less Fatigue in Patients With Inflammatory Bowel Disease Following a Lifestyle Intervention

BACKGROUND

Despite the potential benefits of diet and physical activity, evidence for beneficial effects of a combined lifestyle intervention is lacking in patients with inflammatory bowel disease (IBD). Therefore, we assessed its effects on impact of disease on daily life, clinical disease activity, fatigue, and health-related quality of life (HRQoL) in patients with IBD.

METHODS

A 6-month single-arm intervention study was performed in adult IBD patients in remission or with mildly active disease. Participants received personal dietary and physical activity advice from a dietician and a physiotherapist in 6 consults. At baseline and over time, questionnaires on diet quality, physical activity, and disease-related outcomes were completed and fecal calprotectin was determined. Data were analyzed by linear mixed models.

RESULTS

During the intervention, diet quality significantly increased (P < .001), but the level of physical activity remained the same. Over time, impact of the disease on daily life reduced (P = .009) and fatigue decreased (P = .001), while clinical disease activity, HRQoL, and fecal calprotectin did not change. Improvement in diet quality was significantly associated with a lower impact of disease on daily life (β = 0.09; 95% confidence interval [CI], 0.03 to 0.15; P = .003) and less fatigue (β = -0.13; 95% CI, -0.20 to -0.07; P < .001) but not with clinical disease activity, HRQoL, and fecal calprotectin. No associations were found with physical activity.

CONCLUSIONS

This combined lifestyle intervention significantly improved diet quality, and this improvement was associated with a reduction in the impact of disease on daily life and fatigue in patients with IBD in remission or with mildly active disease.

Effect of the Crohn's Disease Exclusion Diet (CDED) on the Fecal Calprotectin Level in Children with Active Crohn's Disease

(1) Background: The CDED + PEN (partial enteral nutrition) is a promising method of nutritional treatment in active Crohn’s disease (CD). An increase in fecal calprotectin (FCP) level—a marker of mucosal inflammation—happens to be the first evidence of Crohn’s disease exacerbation that appears ahead of clinical symptoms and usually co-exists with them. In this study, we present our own experience with using the CDED + PEN in the treatment of children with CD and an increased FCP level. (2) Methods: In total, 48 children (male/female: 27/21) aged 4−17 years (median value = 13.43; IQR = 4.00) were treated with CDED + PEN between June 2019 and July 2021. The main inclusion criteria for the study was active CD defined as an FCP level ≥ 250.00 µg/g. Patients with severe clinical manifestation of CD (PCDAI >40.00), as well as ones who started any new concomitant CD treatment later than at least 4 weeks before the start of dietary intervention, were excluded from the analysis. The PCDAI and fecal calprotectin level were assessed at weeks 0 and 12. The primary endpoint was ITT normalization of FCP level, i.e., a result < 250.00 µg/g at week 12. The Wilcoxon Matched Pairs Test was used for statistical analysis. (3) Results: The normalization of the FCP level was obtained in 17 children (35.42%) and an FCP level decrease of at least 50% occurred in 26 patients (54.17%). The reduction in fecal calprotectin level between week 0 and week 12 was statistically significant with a median value of 1045.00 µg/g; IQR = 1188.00, and 363.00 µg/g; IQR = 665.00, respectively (p < 0.05). Among 29 patients who were not in clinical remission at baseline, 16 (55.17%) achieved clinical remission (PCDAI < 10.00) at week 12 and 20 (68.97%) obtained a clinical response defined as at least a 12.50 point drop in PCDAI or remission. In this group, the reduction in PCDAI between baseline and week 12 was statistically significant (median value = 20.00 points; IQR = 7.50 and 5.00 points; IQR = 5.00, respectively (p < 0.05)). All patients with a normal FCP level at week 12 were in clinical remission and 16 (94.13%) of them had a normal CRP (C-reactive protein) value. In 10 children (20.83%) the full course of 12 weeks with CDED + PEN was not completed or the concomitant therapy had been started before week 12 due to the lack of efficacy/intolerance of nutritional treatment. (4) Conclusions: The 12-week course of treatment with the CDED + PEN has a beneficial effect on the fecal calprotectin level in children with active CD. The dietary intervention led to a significant decrease in the FCP level in the studied group and to the normalization of this parameter in every third patient.

Lifestyle, behaviour, and environmental modification for the management of patients with inflammatory bowel diseases: an International Organization for Study of Inflammatory Bowel Diseases consensus

Environmental and lifestyle factors play an important role in the natural history of Crohn's disease and ulcerative colitis. A group of international experts from the International Organization for the Study of Inflammatory Bowel Diseases voted on a series of consensus statements to inform the management of inflammatory bowel disease (IBD). The recommendations include avoiding traditional cigarette smoking in patients with Crohn's disease or ulcerative colitis, screening for symptoms of depression, anxiety, and psychosocial stressors at diagnosis and during flares (with referral to mental health professionals when appropriate), and encouraging regular physical activity as tolerated. Patients using dietary approaches for treatment of their IBD should be encouraged to adopt diets that are best supported by evidence and involve monitoring for the objective resolution of inflammation. We recommend formal assessment for obesity and nutritional deficiencies, and patients should be encouraged to maintain a normal body-mass index. A shared decision-making approach to contraception should include the consideration of IBD-related factors, and risk factors for venous thromboembolism. Long-term or frequent use of high-dose non-steroidal anti-inflammatory drugs should be avoided. For primary prevention of disease in the offspring of patients with IBD, we recommend avoiding passive exposure to tobacco, using antibiotics judiciously, and considering breastfeeding when able.

Biomechanical Properties of Strictures in Crohn’s Disease: Can Dynamic Contrast-Enhanced Ultrasonography and Magnetic Resonance Enterography Predict Stiffness?

Strictures and abdominal pain often complicate Crohn’s disease (CD). The primary aim was to explore whether parameters obtained by preoperative contrast-enhanced (CE) ultrasonography (US) and dynamic CE MR Enterography (DCE-MRE) of strictures associates with biomechanical properties. CD patients undergoing elective small intestinal surgery were preoperatively examined with DCE-MRE and CEUS. The excised intestine was distended utilizing a pressure bag. Luminal and outer bowel wall cross-sectional areas were measured with US. The circumferential stricture stiffness (Young’s modulus E) was computed. Stiffness was associated with the initial slope of enhancement on DCE-MRE (ρ = 0.63, p = 0.007), reflecting active disease, but lacked association with CEUS parameters. For structural imaging parameters, inflammation and stricture stiffness were associated with prestenotic dilatation on US (τ_b = 0.43, p = 0.02) but not with MRE (τ_b = 0.01, p = 1.0). Strictures identified by US were stiffer, 16.8 (14.0–20.1) kPa, than those graded as no or uncertain strictures, 12.6 (10.5–15.1) kPa, p = 0.02. MRE global score (activity) was associated with E (ρ = 0.55, p = 0.018). Elastography did not correlate with circumferential stiffness. We conclude that increasing activity defined by the initial slope of enhancement on DCE-MRE and MRE global score were associated with stricture stiffness. Prestenotic dilatation on US could be a potential biomarker of CD small intestinal stricture stiffness.

Systematic review with meta-analysis: dietary intake in adults with inflammatory bowel disease

BACKGROUND

Poor dietary intake is associated with the development of malnutrition, micronutrient deficiencies, anaemia and osteoporosis in individuals with inflammatory bowel disease. While trials are underway to manipulate the diet of people with IBD, there has been no comprehensive systematic review of the dietary intake of adults with IBD.

AIMS

To conduct a systematic evaluation and meta-analysis of the dietary intake of adults with IBD, including macronutrients, micronutrients and food group data.

METHODS

CINAHL, Embase, Medline and Scopus were searched from 1 January 2000 to 25 September 2020 for cohort, case-control or cross-sectional studies that reported usual dietary intake in adults. Data were pooled and reported as weighted mean intake for: all adults with IBD; Crohn's disease; ulcerative colitis; active disease; remission; males; females. A random-effects meta-analysis model compared intake with healthy individuals.

RESULTS

Forty studies were identified and 19 were included in the meta-analysis. All subgroups of adults with IBD consumed inadequate energy (mean intake in adults with IBD 1980 ± 130 kcal), fibre (14 ± 4 g), folate (246 ± 33 mg) and calcium (529 ± 114 mg) per day. Intake of breads and cereals, legumes, fruit, vegetables and dairy were inadequate. Compared to healthy individuals, adults with IBD consume significantly less dietary fibre (SMD -0.59; 95% CI: -0.73, -0.46).

CONCLUSIONS

This review provides improved clarity about the dietary intake of adults with IBD. Future attention is required to improve diet quality and increase understanding of factors influencing dietary intake in IBD.

Effects of oral vitamin D supplementation on inflammatory bowel disease: a systematic review and meta-analysis

Vitamin D (VitD) is a fat-soluble micronutrient that plays a critical role in inflammatory bowel disease (IBD). Although the effective properties of VitD in anti-inflammatory and immune moderation were reviewed, some important issues still remain uncovered. Considering the practicability and high bioavailability, as a more recommended therapeutic approach, the effects of oral VitD supplementation on IBD remain inconclusive. This study aims to investigate the effect and safety of oral VitD supplementation on IBD patients, which has already been registered on PROSPERO (no. CRD42020165045). A pooled analysis of 17 trials with 1127 patients revealed that as a safety therapeutic strategy, oral VitD supplementation effectively increased the concentration of serum 25-hydroxyvitamin D [weighted mean difference 12.15 ng mL^-1; 95% confidence interval (CI) 9.26, 15.03; I² = 90%] and decreased serum C-reactive protein levels [standard mean difference (SMD) -0.33; 95% CI -0.61, -0.05; I² = 55%], but it did not decrease erythrocyte sedimentation rate levels (SMD 0.35; 95% CI -4.33, 5.03; I² = 57%), disease activity index (SMD -0.13; 95% CI -0.66, 0.39; I² = 84%) and relapse rate (RR 0.59; 95% CI 0.19, 1.86; I² = 79%). These findings suggest that oral VitD supplementation has a role to play in the therapeutic management of IBD. These findings may contribute to public health and clinical dietary guidelines and improve the health of IBD patients.

Nutritional Therapy in Pediatric Crohn's Disease-Are We Going to Change the Guidelines?

In recent years, there has been a significant increase in the incidence of Crohn’s disease. Despite significant medical progress, the treatment options available today do not meet the needs of all patients. Recent reports indicate that external environmental factors, including diet, are key in the pathomechanism of the disease. It was proven that the so-called Western dietary pattern is associated with an increased risk of disease. In the pediatric population, exclusive enteral nutrition is the only nutritional therapy option recommended today with proven high efficacy in inducing remission. Recent publications that indicate at least comparable efficacy and significantly better tolerability of a specialised elimination diet, the Crohn’s Disease Exclusion Diet (CDED), provide the basis for a change in recommendations. This article discusses the mechanism of action, principles of use, and scientific evidence evaluating the efficacy of CDED in the treatment of children with Crohn’s disease.

Fish Sidestream-Derived Protein Hydrolysates Suppress DSS-Induced Colitis by Modulating Intestinal Inflammation in Mice

Inflammatory bowel disease is characterized by extensive intestinal inflammation, and therapies against the disease target suppression of the inflammatory cascade. Nutrition has been closely linked to the development and suppression of inflammatory bowel disease, which to a large extent is attributed to the complex immunomodulatory properties of nutrients. Diets containing fish have been suggested to promote health and suppress inflammatory diseases. Even though most of the health-promoting properties of fish-derived nutrients are attributed to fish oil, the potential health-promoting properties of fish protein have not been investigated. Fish sidestreams contain large amounts of proteins, currently unexploited, with potential anti-inflammatory properties, and may possess additional benefits through bioactive peptides and free amino acids. In this project, we utilized fish protein hydrolysates, based on mackerel and salmon heads and backbones, as well as flounder skin collagen. Mice fed with a diet supplemented with different fish sidestream-derived protein hydrolysates (5% w/w) were exposed to the model of DSS-induced colitis. The results show that dietary supplements containing protein hydrolysates from salmon heads suppressed chemically-induced colitis development as determined by colon length and pro-inflammatory cytokine production. To evaluate colitis severity, we measured the expression of different pro-inflammatory cytokines and chemokines and found that the same supplement suppressed the pro-inflammatory cytokines IL-6 and TNFα and the chemokines Cxcl1 and Ccl3. We also assessed the levels of the anti-inflammatory cytokines IL-10 and Tgfb and found that selected protein hydrolysates induced their expression. Our findings demonstrate that protein hydrolysates derived from fish sidestreams possess anti-inflammatory properties in the model of DSS-induced colitis, providing a novel underexplored source of health-promoting dietary supplements.

Let Food Be Thy Medicine-Its Role in Crohn's Disease

The food we eat is thought to play a role in both the increasing incidence as well as the course of Crohn's disease. What to eat and what to avoid is an increasingly important question for both patients and physicians. Restrictive diets are widely adopted by patients and carry the risk of inducing or worsening malnutrition, without any guarantees on anti-inflammatory potential. Nevertheless, exploration of novel therapies to improve long-term management of the disease is desperately needed and the widespread use of exclusive enteral nutrition in the induction of paediatric Crohn's disease makes us wonder if a similar approach would be beneficial in adult patients. This narrative review discusses the current clinical evidence on whole food diets in achieving symptomatic and inflammatory control in Crohn's disease and identifies knowledge gaps with areas for future research.

Predefined Diets in Patients with Inflammatory Bowel Disease: Systematic Review and Meta-Analysis

Inflammatory bowel disease (IBD) is a chronic disease mediated by the immune system and characterized by the importance of diet in pathological development. This study aims to understand how the use of predefined diets can affect the adult population diagnosed with IBD. We conducted a systematic review and meta-analysis. From the different databases (MEDLINE, Scopus, Cochrane, LILACS, CINAHL, and WOS), we found 4195 registers. After a review process, only 31 research studies were selected for qualitative synthesis and 10 were selected for meta-analysis. The variables used were Crohn’s Disease Activity Index (CDAI) for patients with Crohn’s Disease (CD) and fecal calprotectin (FC), C-Reactive Protein (CRP), and albumin (ALB) for patients with IBD. Predefined diets have been shown to have partial efficacy for the treatment of IBD and are compatible with other medical treatments. CDAI improved but with reasonable doubts due to the high heterogeneity of the data, while no differences were observed for ALB, FC, and CRP. More studies that evaluate the influence of predefined diets on IBD patients are needed due to the great variability in diets and the tools used to measure their effects.

Diet Advice for Crohn's Disease: FODMAP and Beyond

Crohn’s disease (CD) is a chronic, progressive, and destructive granulomatous inflammatory bowel disorder that can involve any part of the gastrointestinal tract. It has been presumed that different types of diet might improve gastrointestinal symptoms in CD patients. The aim of this review was to clarify the efficiency and indications of a low-“fermentable oligo-, di-, mono-saccharides and polyols” (FODMAP) diet (LFD) in CD and to further analyze the available data on other types of diets. PubMed, Cochrane Library, EMBASE and WILEY databases were screened for relevant publications regarding the effect of FODMAP diets on CD. Our search identified 12 articles analyzing the effect of an LFD in CD, 5 articles analyzing the effect of a Mediterranean diet (MD), 2 articles analyzing the effect of a vegetarian diet (VD), and 2 articles analyzing the effect of a low-lactose diet (LLD). The majority of the studies included in this review show the significant efficiency of the LFD in CD patients. We found significant evidence demonstrating that the LFD has a favorable impact on gastrointestinal symptoms in CD patients. Notwithstanding the evidence, it remains to be established if an LFD is more efficient than other types of diets in the short term and especially in the long term.

The association between inflammatory potential of diet and disease activity: results from a cross-sectional study in patients with inflammatory bowel disease

BACKGROUND

Diet may play a role in disease status in patients with inflammatory bowel disease. We tested whether the inflammatory potential of diet, based on a summation of pro- and anti-inflammatory nutrients, is associated with disease activity in patients with Crohn's disease and ulcerative colitis.

METHODS

Participants completed a disease activity questionnaire (short Crohn's Disease Activity (sCDAI) or Patient Simple Clinical Colitis Activity Index (P-SCCAI)) and a Food Frequency Questionnaire (FFQ). FFQ data were used to calculate the Dietary Inflammatory Index (DII) which enables categorization of individuals' diets according to their inflammatory potential on a continuum from pro- to anti-inflammatory. Associations with disease activity were investigated by multiple linear regression.

RESULTS

The analysis included 329 participants; 168 with Crohn's disease (median sCDAI score 93 [IQR 47-156]), and 161 with ulcerative colitis (median P-SCCAI score 1 [IQR 1-3]). Mean DII was 0.71 ± 1.33, suggesting a slightly pro-inflammatory diet. In Crohn's disease, the DII was positively associated with disease activity, even after adjustment for confounders (p = 0.008). The mean DII was significantly different between participants in remission and with mild and moderately active disease (0.64, 0.97 and 1.52 respectively, p = 0.027). In ulcerative colitis, the association was not significant.

CONCLUSIONS

Disease activity was higher in IBD participants with a more pro-inflammatory diet with statistical significance in Crohn's disease. Although the direction of causality is not clear, this association strengthens the role for diet in medical treatment, which should be tested in an intervention study.

Dietary patterns, beliefs and behaviours among individuals with inflammatory bowel disease: a cross-sectional study

BACKGROUND

Inflammatory bowel disease (IBD) refers to a group of incurable gastrointestinal diseases that are common among young adults. The present study aimed to describe dietary intake, self-modifications and beliefs among adults aged 18-35 years with IBD and to compare those with active versus inactive disease. National guidelines for daily intake include: 34 g of fibre for males and 28 g of fibre for females, 3 oz of whole grains, 1000 mg of calcium, <10% of added sugars, three cups of dairy, 2.5 cups of vegetables and two cups of fruit.

METHODS

Individuals with a diagnosis of IBD were recruited online using convenience sampling (n = 147). Data included a dietary screening questionnaire, self-directed diet modifications, dietary beliefs questionnaire and demographics. Chi-squared and t-tests were used to compare those with active versus inactive disease.

RESULTS

The sample was predominantly female (90%) and diagnosed with Crohn's disease (64%). Daily intake for females was 9.7 g of fibre, 0.3 oz of whole grains, 683.8 g of calcium, 1.1 of cups vegetables and 0.5 of cups fruit. Daily intake for males was 14.2 g of fibre, 0.4 oz of whole grains, 882.9 g of calcium, 1.4 cups of vegetables and 0.5 cups of fruit. Participants most often modified fibre (73%), fruits and vegetables (71%), grains (67%), and dairy (66%) as a result of their IBD. Eighty-three percent believed that modifying their diet could reduce IBD symptoms.

CONCLUSIONS

Both men and women with IBD struggle to meet the national guidelines for intake of fibre, whole grains, fruits and vegetables. The majority reported modifying their dietary intake as a result of IBD and expressed belief that diet could reduce symptoms.

The role of a plant-based diet in the pathogenesis, etiology and management of the inflammatory bowel diseases

Introduction: Inflammatory Bowel Disease (IBD) carries a significant burden on an individual's quality-of-life and on the healthcare system. The majority of patients use dietary modifications to manage their symptoms, despite limited research to support these changes. There is emerging data that a plant-based diet will be of benefit to IBD patients.Areas covered: A literature review on the pathogenesis and potential benefits of dietary management of IBD.Expert opinion: A Westernized diet has been associated with IBD risk and relapse; hence a plant-based diet may be of benefit to IBD patients through reducing inflammation and restoring symbiosis. Dietary therapy can be an important adjunct therapy, however, better quality studies are still required.

Dietary strategies and food practices of pediatric patients, and their parents, living with inflammatory bowel disease: a qualitative interview study

Purpose: A growing body of scientific evidence supports the role of food and diet in the pathogenesis and management of inflammatory bowel diseases (IBD). However, little is known about the role of food and diet from the perspectives of pediatric patients and their parents. This study aimed to explore how children and adolescents with IBD and their parents coped with the illness through food and diet in their daily lives.

Methods: We conducted semi-structured interviews with 28 children and adolescents with IBD, 26 parents and one grandparent.

Results: Two major themes, dietary strategies and family food practices, were identified through thematic analysis. There were three types of dietary strategies: food avoidance and moderation; following a specific diet; and healthy eating. For family food practices, two subthemes were identified: impact on grocery shopping, meal planning, and cooking; and maintaining routine and normality.

Conclusions: Our findings have important implications for the clinical care of pediatric IBD. Notably, IBD not only influenced the food practices of the pediatric patients, but also their parents and other family members. Healthcare professionals should consider the family unit when giving nutritional advice or developing nutritional guidelines. Personalized nutritional counselling and ongoing nutritional assessment are also warranted.

ESPEN practical guideline: Clinical Nutrition in inflammatory bowel disease

The present guideline is the first of a new series of "practical guidelines" based on more detailed scientific guidelines produced by ESPEN during the last few years. The guidelines have been shortened and now include flow charts that connect the individual recommendations to logical care pathways and allow rapid navigation through the guideline. The purpose of the present practical guideline is to provide an easy-to-use tool to guide nutritional support and primary nutritional therapy in inflammatory bowel disease (IBD). The guideline is aimed at professionals working in clinical practice, either in hospitals or in outpatient medicine, and treating patients with IBD. In 40 recommendations, 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.

Self-Management Through Social Support Among Emerging Adults With Inflammatory Bowel Disease

BACKGROUND

Emerging adulthood is a unique developmental stage, which may affect individuals' self-management behaviors, social support, and the relationship between these two constructs. Among older adults, social support has been shown to improve self-management behaviors for individuals with chronic conditions; however, this relationship has not been examined with emerging adults (age 18-29 years) who have inflammatory bowel disease (IBD).

OBJECTIVES

The aim of the study was to examine the relationship between two conceptualizations of social support (received and perceived availability of social support) and IBD-related self-management behaviors among emerging adults with IBD.

METHODS

A convenience sample of emerging adult IBD individuals (currently prescribed medication to manage IBD) were recruited through ResearchMatch, Facebook, and word of mouth. The study was guided by key elements of the individual and family self-management theory. Participants responded to demographic and condition-specific questionnaires: the Inventory of Dimensions of Emerging Adulthood, the Inventory of Socially Supportive Behaviors, the Medical Outcomes: Social Support Survey, the Medication Adherence Report Scale, and the Dietary Screener Questionnaire.

RESULTS

Emerging adults with high received informational support reported greater medication adherence compared to those with low received informational support when controlling for biological medications, time since diagnosis, symptom frequency, and feeling in-between adolescence and adulthood. Neither type of social support was associated with diet modification.

DISCUSSION

Received informational social support, medication type, time since diagnosis, symptoms, and emerging adulthood factors have the potential to influence medication adherence. Received informational social support interventions, such as patient-to-patient or group-based mentoring, may serve to improve medication adherence among emerging adults with IBD.

Nutrition Center of Excellence (COE) in Inflammatory Bowel Disease-A Model and Rationale for Development

Goals

The goal of this study was to develop a multi-disciplinary consensus of nutrition care priorities for implementation in an IBD nutrition center of excellence (COE).

Background

The role for nutrition care in inflammatory bowel disease is broad and encompasses multiple domains. Gaps exist in the published literature around best nutrition care practices in inflammatory bowel disease and highlight the need for an evidence based approach acceptable to patients, and generalizable to a wide inflammatory bowel disease population.

Study

Twelve health leaders in inflammatory bowel disease care attended a 1-day retreat. Two focus groups were completed using traditional focus group methodology for the first half of the retreat and a World Café method for the second half. Data analysis included review of analytic memos and conceptual analysis completed at the time of discussion, theme identification and team consensus for conceptual development.

Results

Three primary themes were identified as the main pillars of a COE in an IBD nutrition center of excellence. These include: a) excellence in clinical care, b) novel discovery and research, and c) knowledge translation to patients and practitioners. The key initial steps identified in this study included standardizing malnutrition screening and support while creating an environment where nutrition therapy is included as a standard of care, developing and examining the effectiveness of novel diet therapies, and translating knowledge to build capacity among care providers and patients.

Conclusions

Using a 1-day retreat to identify a future direction for a center focused on nutrition excellence and align our coalition towards common goals was a successful strategy to develop consensus and identify nutrition care priorities for action.

Effect of a Milk-Based Fruit Beverage Enriched with Plant Sterols and/or Galactooligosaccharides in a Murine Chronic Colitis Model

The potential anti-inflammatory effect of plant sterols (PS) enriched milk-based fruit beverages (PS, 1 g/100 mL) (MfB) with/without galactooligosaccharides (GOS, 2 g/100 mL) (MfB-G) in an experimental mice model of chronic ulcerative colitis was evaluated. Beverages were orally administered to mice every day by gavage to achieve PS and GOS doses of 35 and 90 mg/kg, respectively, and experimental colitis was induced by giving mice drinking water ad libitum containing 2% (w/v) dextran sulphate sodium (DSS) for 7 days, alternating with periods without DSS up to the end of the study (56 days). MfB beverage showed significant reduction of symptoms associated to ulcerative colitis and improved the colon shortening and mucosal colonic damage, but it was not able to reduce the increase of myeloperoxidase levels produced by DSS. MfB-G showed higher incidence of bloody feces and loss of stool consistency than MfB, as well as high levels of immune cells infiltration in colon tissue and myeloperoxidase. Therefore, PS-enriched milk-based fruit beverage could be an interesting healthy food to extend the remission periods of the diseases and the need to evaluate, in a pre-clinical model, the anti-inflammatory effect of the combination of bioactive compounds in the context of a whole food matrix.

The role of dietary factors in inflammatory bowel diseases: New perspectives

The current review aimed to elucidate the role of diet in every stage of inflammatory bowel diseases, from aspects of prevention, treatment and rehabilitation. Western diet, characterized by overconsumption of refined sugar and saturated fat and low consumption of dietary fiber, may partly be blamed for its pathogenesis. Some immune-modulated nutrients (fibers, monounsaturated fatty acids, n-3 polyunsaturated fatty acids and vitamin D) exert their potential beneficial effects on gut microbiota and immune function, resulting in clinical remission and/or preventing relapse. However, data is limited to conclude optimal micronutrient levels and therapeutic implications. Further, diet itself is complex; therefore, it is reasonable to evaluate diet as a whole rather than a single type of food. Some specific dietary patterns are generated for the management of inflammatory bowel diseases with controversial results. Only exclusive enteral nutrition has been widely recommended for pediatric patients with non-stricturing active Crohn's disease. Self-monitoring, avoidance of certain types of foods, limited intake of alcohol and smoking, supplementation of minerals and vitamins if deficiency is confirmed, and adherence to the diet enriched in vegetables and fruits and low in animal food and un-digested fiber during flares are the most common dietary recommendation. Further clinical trials with a high evidence rank are warranted.

The role of diet in the aetiopathogenesis of inflammatory bowel disease

Crohn's disease and ulcerative colitis, collectively known as IBD, are chronic inflammatory disorders of the gastrointestinal tract. Although the aetiopathogenesis of IBD is largely unknown, it is widely thought that diet has a crucial role in the development and progression of IBD. Indeed, epidemiological and genetic association studies have identified a number of promising dietary and genetic risk factors for IBD. These preliminary studies have led to major interest in investigating the complex interaction between diet, host genetics, the gut microbiota and immune function in the pathogenesis of IBD. In this Review, we discuss the recent epidemiological, gene-environment interaction, microbiome and animal studies that have explored the relationship between diet and the risk of IBD. In addition, we highlight the limitations of these prior studies, in part by explaining their contradictory findings, and review future directions.

Effect of Dietary Fiber and Metabolites on Mast Cell Activation and Mast Cell-Associated Diseases

Many mast cell-associated diseases, including allergies and asthma, have seen a strong increase in prevalence during the past decades, especially in Western(ized) countries. It has been suggested that a Western diet may contribute to the prevalence and manifestation of allergies and asthma through reduced intake of dietary fiber and the subsequent production of their metabolites. Indeed, dietary fiber and its metabolites have been shown to positively influence the development of immune disorders via changes in microbiota composition and the regulation of B- and T-cell activation. However, the effects of these dietary components on the activation of mast cells, key effector cells of the inflammatory response in allergies and asthma, remain poorly characterized. Due to their location in the gut and vascularized tissues, mast cells are exposed to high concentrations of dietary fiber and/or its metabolites. Here, we provide a focused overview of current findings regarding the direct effects of dietary fiber and its various metabolites on the regulation of mast cell activity and the pathophysiology of mast cell-associated diseases.

The utility of food antigen test in the diagnosis of Crohn's disease and remission maintenance after exclusive enteral nutrition

BACKGROUND

Crohn's disease (CD) involves intensive immunologic responses to food antigens. Exclusive enteral nutrition (EEN) showed efficacy in inducing disease remission. However, relapse commonly occurred when normal diet was reintroduced. We aimed to investigate the food-specific IgG antibodies of CD, and clarify the effects of exclusion diet guided by food-specific antibodies on remission maintenance after EEN.

METHODS

All available data of food-specific antibodies were retrieved from the database and analyzed for the diagnostic value. Thereafter, we retrospectively recruited qualified patients who reintroduced their diet excluding the moderately and strongly immunoreactive foods with prospective follow-up data. Matched patients without diet intervention after EEN served as control. CD activity index (CDAI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and endoscopic score were compared.

RESULTS

A significantly enhanced immune response to rice, tomato, egg white/egg yolk and maize was observed in CD patients. The number of IgG-positive items had the greatest power to discriminate CD from ulcerative colitis and the control group with area under the curve of 0.819 and 0.828. Each diet group included 32 patients, and disease relapsed in 12.5% of the exclusion group compared with 25% of the control. The increase of CDAI and ESR was more remarkable in the control group than in the exclusion diet group (P<0.05).

CONCLUSIONS

CD patients presented intensive immune responses to food antigens. The number of IgG-positive food items had potential to be a diagnostic marker of CD. Diet guided by food antibody test might help maintain disease remission.

Nutrition in Pediatric Inflammatory Bowel Disease: A Position Paper on Behalf of the Porto Inflammatory Bowel Disease Group of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND AND AIMS

A growing body of evidence supports the need for detailed attention to nutrition and diet in children with inflammatory bowel disease (IBD). We aimed to define the steps in instituting dietary or nutritional management in light of the current evidence and to offer a useful and practical guide to physicians and dieticians involved in the care of pediatric IBD patients.

METHODS

A group of 20 experts in pediatric IBD participated in an iterative consensus process including 2 face-to-face meetings, following an open call to Nutrition Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition Porto, IBD Interest, and Nutrition Committee. A list of 41 predefined questions was addressed by working subgroups based on a systematic review of the literature.

RESULTS

A total of 53 formal recommendations and 47 practice points were endorsed with a consensus rate of at least 80% on the following topics: nutritional assessment; macronutrients needs; trace elements, minerals, and vitamins; nutrition as a primary therapy of pediatric IBD; probiotics and prebiotics; specific dietary restrictions; and dietary compounds and the risk of IBD.

CONCLUSIONS

This position paper represents a useful guide to help the clinicians in the management of nutrition issues in children with IBD.

Dietary practices and inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) remains elusive but it is believed to result from incompletely understood interactions between environmental triggers in a potentially genetically susceptible host and a subsequent aberrant immune response. Its incidence is increasing worldwide at an unprecedented rate, outpacing what genetic influences alone could instigate. The increasingly integral role played by eating in social life has led patients to gravitate to diet and food in their consultations with physicians and other health care professionals, in an attempt to improve, control, or even "cure" IBD through diet. Diet is a modifiable factor, and both patients and healthcare professionals have fuelled resurgent interest in the role of diet in maintaining IBD remission. Despite significant and increasing interest, there is a lack of credible evidence to support dietary modification or restrictions to prevent relapse of IBD. However, recent studies have shown that more than half of the patients believe that diet plays an important role in triggering relapse, leading to self-imposed dietary restrictions, some of which can have adverse consequences. This underpins the need for physicians and health care professionals to have a better understanding of dietary practices, in triggering, perpetuating, and improving IBD. This review examines and discusses the evidence behind this.

The Imbalance between n-6/n-3 Polyunsaturated Fatty Acids and Inflammatory Bowel Disease: A Comprehensive Review and Future Therapeutic Perspectives

Eating habits have changed dramatically over the years, leading to an imbalance in the ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) in favour of n-6 PUFAs, particularly in the Western diet. Meanwhile, the incidence of inflammatory bowel disease (IBD) is increasing worldwide. Recent epidemiological data indicate the potential beneficial effect of n-3 PUFAs in ulcerative colitis (UC) prevention, whereas consumption of a higher ratio of n-6 PUFAs versus n-3 PUFAs has been associated with an increased UC incidence. The long-chain dietary n-3 PUFAs are the major components of n-3 fish oil and have been shown to have anti-inflammatory properties in several chronic inflammatory disorders, being involved in the regulation of immunological and inflammatory responses. Despite experimental evidence implying biological plausibility, clinical data are still controversial, especially in Crohn’s disease. Clinical trials of fish-oil derivatives in IBD have produced mixed results, showing beneficial effects, but failing to demonstrate a clear protective effect in preventing clinical relapse. Such data are insufficient to make a recommendation for the use of n-3 PUFAs in clinical practice. Here, we present the findings of a comprehensive literature search on the role of n-3 PUFAs in IBD development and treatment, and highlight new therapeutic perspectives.

Etiopathogenesis of inflammatory bowel disease: today and tomorrow

PURPOSE OF REVIEW

Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), represent chronic diseases of unknown cause, and they are regarded as prototypical complex diseases. Despite all the recent advances, a complete appreciation of the pathogenesis of IBD is still limited. In this review, we present recent information contributing to a better understanding of mechanisms underlying IBD.

RECENT FINDINGS

Here, we attempt to highlight novel environmental triggers, data on the gut microbiota, its interaction with the host, and the potential influence of diet and food components. We discuss recent findings on defective signaling pathways and the potential effects on the immune response, and we present new data on epigenetic changes, inflammasome, and damage-associated molecular patterns associated with IBD.

SUMMARY

The continuing identification of several epigenetic, transcriptomic, proteomic, and metabolomic alterations in patients with IBD reflects the complex nature of the disease and suggests the need for innovative approaches such as systems biology for identifying novel relevant targets in IBD.

Effects of Non-Starch Polysaccharides on Inflammatory Bowel Disease

The incidence of inflammatory bowel disease (IBD) has increased considerably over the past few decades. In the present review, we discuss several disadvantages existing in the treatment of IBD and current understandings of the structures, sources, and natures of various kinds of non-starch polysaccharides (NSPs). Available evidences for the use of different sources of NSPs in IBD treatment both in vitro and in vivo are analyzed, including glucan from oat bran, mushroom, seaweed, pectin, gum, prebiotics, etc. Their potential mechanisms, especially their related molecular mechanism of protective action in the treatment and prevention of IBD, are also summarized, covering the anti-inflammation, immune-stimulating, and gut microbiota-modulating activities, as well as short-chain fatty acids (SCFAs) production, anti-oxidative stress accompanied with inflammation, the promotion of gastric epithelial cell proliferation and tissue healing, and the reduction of the absorption of toxins of NSPs, thus ameliorating the symptoms and reducing the reoccurrence rate of IBD. In summary, NSPs exhibit the potential to be promising agents for an adjuvant therapy and for the prevention of IBD. Further investigating of the crosstalk between immune cells, epithelial cells, and gut microorganisms in addition to evaluating the effects of different kinds and different molecular weights of NSPs will lead to well-designed clinical intervention trials and eventually improve the treatment and prevention of IBD.

Is a low FODMAP diet beneficial for patients with inflammatory bowel disease? A meta-analysis and systematic review

BACKGROUND & AIMS

To assess the current evidence regarding the benefit of a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diet in the treatment of patients with inflammatory bowel disease (IBD).

METHODS

Databases such as PubMed, Web of Science, Medline were comprehensively searched for relevant studies through January 2017. The pooled odds ratio (OR) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were used to analyze the dichotomous variables (diarrhea response, abdominal pain and bloating, etc.) and the continuous variables. Random- and fixed-effects models were chosen according to heterogeneity.

RESULTS

Two RCTs and four before-after studies with a total of 319 patients (96% in remission) were identified. Except for the constipation response, there was a significant improvement in other symptoms: diarrhea response (OR: 0.24, 95% CI: 0.11-0.52, p = 0.0003), satisfaction with gut symptoms (OR: 26.84, 95% CI: 4.6-156.54, p < 0.00001), abdominal bloating (OR: 0.10, 95% CI: 0.06-0.16, p < 0.00001), abdominal pain (OR: 0.24, 95% CI: 0.16-0.35, p < 0.00001), fatigue (OR: 0.40, 95% CI: 0.24-0.66, p = 0.0003) and nausea (OR: 0.51, 95% CI: 0.31-0.85, p = 0.009).

CONCLUSIONS

The present meta-analysis offers proof to support that a low FODMAP diet is beneficial for reducing gastrointestinal symptoms in patients with quiescent IBD. With the inherent limitations, the findings of this analysis remain to be confirmed and updated by further high-volume, well-designed and long-term follow-up studies.

Diet and microbiota in inflammatory bowel disease: The gut in disharmony

Bacterial colonization of the gut shapes both the local and the systemic immune response and is implicated in the modulation of immunity in both healthy and disease states. Recently, quantitative and qualitative changes in the composition of the gut microbiota have been detected in Crohn's disease and ulcerative colitis, reinforcing the hypothesis of dysbiosis as a relevant mechanism underlying inflammatory bowel disease (IBD) pathogenesis. Humans and microbes have co-existed and co-evolved for a long time in a mutually beneficial symbiotic association essential for maintaining homeostasis. However, the microbiome is dynamic, changing with age and in response to environmental modifications. Among such environmental factors, food and alimentary habits, progressively altered in modern societies, appear to be critical modulators of the microbiota, contributing to or co-participating in dysbiosis. In addition, food constituents such as micronutrients are important regulators of mucosal immunity, with direct or indirect effects on the gut microbiota. Moreover, food constituents have recently been shown to modulate epigenetic mechanisms, which can result in increased risk for the development and progression of IBD. Therefore, it is likely that a better understanding of the role of different food components in intestinal homeostasis and the resident microbiota will be essential for unravelling the complex molecular basis of the epigenetic, genetic and environment interactions underlying IBD pathogenesis as well as for offering dietary interventions with minimal side effects.

Diet and the Microbiome

The gut microbiota provides a range of ecologic, metabolic, and immunomodulatory functions relevant to health and well-being. The gut microbiota not only responds quickly to changes in diet, but this dynamic equilibrium may be managed to prevent and/or treat acute and chronic diseases. This article provides a working definition of the term "microbiome" and uses two examples of dietary interventions for the treatment of large bowel conditions to emphasize the links between diet and microbiome. There remains a need to develop a better functional understanding of the microbiota, if its management for clinical utility is to be fully realized.

Diet as a Trigger or Therapy for Inflammatory Bowel Diseases

The most common question asked by patients with inflammatory bowel disease (IBD) is, "Doctor, what should I eat?" Findings from epidemiology studies have indicated that diets high in animal fat and low in fruits and vegetables are the most common pattern associated with an increased risk of IBD. Low levels of vitamin D also appear to be a risk factor for IBD. In murine models, diets high in fat, especially saturated animal fats, also increase inflammation, whereas supplementation with omega 3 long-chain fatty acids protect against intestinal inflammation. Unfortunately, omega 3 supplements have not been shown to decrease the risk of relapse in patients with Crohn's disease. Dietary intervention studies have shown that enteral therapy, with defined formula diets, helps children with Crohn's disease and reduces inflammation and dysbiosis. Although fiber supplements have not been shown definitively to benefit patients with IBD, soluble fiber is the best way to generate short-chain fatty acids such as butyrate, which has anti-inflammatory effects. Addition of vitamin D and curcumin has been shown to increase the efficacy of IBD therapy. There is compelling evidence from animal models that emulsifiers in processed foods increase risk for IBD. We discuss current knowledge about popular diets, including the specific carbohydrate diet and diet low in fermentable oligo-, di-, and monosaccharides and polyols. We present findings from clinical and basic science studies to help gastroenterologists navigate diet as it relates to the management of IBD.

Potential Benefits of Dietary Fibre Intervention in Inflammatory Bowel Disease

Intestinal dysbiosis is thought to be an important cause of disease progression and the gastrointestinal symptoms experienced in patients with inflammatory bowel disease (IBD). Inflammation appears to be a major contributor in perpetuating a dysregulated gut microbiota. Although current drug therapies can significantly induce and maintain disease remission, there is no cure for these diseases. Nevertheless, ongoing human studies investigating dietary fibre interventions may potentially prove to exert beneficial outcomes for IBD. Postulated mechanisms include direct interactions with the gut mucosa through immunomodulation, or indirectly through the microbiome. Component species of the microbiome may degrade dietary-fibre polysaccharides and ferment the products to form short-chain fatty acids such as butyrate. Prebiotic dietary fibres may also act more directly by altering the composition of the microbiome. Longer term benefits in reducing the risk of more aggressive disease or colorectal cancer may require other dietary fibre sources such as wheat bran or psyllium. By critically examining clinical trials that have used dietary fibre supplements or dietary patterns containing specific types or amounts of dietary fibres, it may be possible to assess whether varying the intake of specific dietary fibres may offer an efficient treatment for IBD patients.

A review of the efficacy of dietary polyphenols in experimental models of inflammatory bowel diseases

Crohn's disease and ulcerative colitis presently have no cure and are treated with anti-inflammatory drugs or monoclonal antibodies targeting pro-inflammatory cytokines. A variety of rodent models have been used to model chronic and acute colitis. Dietary polyphenols in foods and botanicals are of considerable interest for prevention and treatment of colitis. Many dietary polyphenols have been utilized for prevention of colitis in rodent models. Berries, green tea polyphenols, curcumin, and stilbenes have been the most extensively tested polyphenols in rodent models of colitis. The majority of polyphenols tested have inhibited colitis in rodents, but increasing doses of EGCG and green tea, isoflavones, flaxseed, and α-mangostin have exacerbated colitis. Few studies have examined combination of polyphenols or other bioactives for inhibition of colitis. Translating polyphenol doses used in rodent models of colitis to human equivalent doses reveals that supplemental doses are most likely required to inhibit colitis from a single polyphenol treatment. The ability to translate polyphenol treatments in rodent models is likely to be limited by species differences in xenobiotic metabolism and microbiota. Given these limitations, data from polyphenols in rodent models suggests merit for pursuing additional clinical studies for prevention of colitis.

Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

AIM: To evaluate ATP-binding cassette (ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer (CRC) development.

METHODS: Literature search was conducted on PubMed using combinations of the following terms: ABC transporters, ATP binding cassette transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1/Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function.

RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in relation to colitis was suggested by the animal studies. The finding that colitis was preceded by altered gut bacterial composition suggests that deletion of Abcb1 leads to fundamental changes of host-microbiota interaction. Also, high fat diet increases the frequency and severity of colitis in specific pathogen-free Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters and which may additionally affect ABC transporter function through nuclear receptors and transcriptional regulation. Another critical role of ABCB1 was suggested by the finding that ABCB1 expression identifies a subpopulation of pro-inflammatory Th17 cells which were resistant to treatment with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak.

CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies.