Fibre intake and the development of inflammatory bowel disease: A European prospective multi-centre cohort study (EPIC-IBD)

The association of ultra-processed food consumption with adult inflammatory bowel disease risk: a systematic review and dose-response meta-analysis of 4 035 694 participants

CONTEXT

There is an inconsistency between the results obtained from observational studies regarding intake of ultra-processed foods (UPFs) and the risk of inflammatory bowel disease (IBD).

OBJECTIVES

A dose-response meta-analysis was performed to evaluate the relationship between UPF intake and the risk of IBD.

DATA SOURCES

Searches were performed in the PubMed, ISI Web of Science, and Scopus databases up to November 2, 2022.

DATA EXTRACTION

Data were available from 24 studies including a total of 4 035 694 participants from 20 countries.

DATA ANALYSIS

Risk ratios for IBD were analyzed by a random-effects model. Outcomes indicated that UPF intake was linked to an increased risk of IBD (relative risk [RR], 1.13; 95%CI, 1.06-1.21; P = 0.001; I2 = 73.2%; n = 59; N = 4 035 694). This association was significant, especially for the risk of Crohn's disease (CD) (RR, 1.19; 95%CI, 1.00-1.41; I2 = 78.2%; P = 0.046; n = 23; N = 2 167 160), unlike the risk of ulcerative colitis (UC) (RR = 1.11; 95%CI, 0.99-1.26; P = 0.085; I2 = 60.3%; n = 27; N = 2 167 918). Also, results revealed that each 10% enhancement in daily UPF intake was not related to the risk of IBD (RR, 1.05; 95%CI, 0.98-1.14; P = 0.168; I2 = 31.9%; n = 4) or the risk of UC (RR, 1.01; 95%CI, 0.92-1.11; P = 0.876; I2 = 34.7%; n = 2) in adults. However, results suggested that for every 10% increase in daily UPF intake, there was a 19% increase in the risk of CD (RR, 1.19; 95%CI, 1.01-1.32; P = 0.021; I2 = 0.0%; n = 2) among adults. In addition, the results showed a positive linear relation between UPF intake with CD risk (Pnonlinearity = 0.431; Pdose response = 0.049) but not risk of IBD or UC.

CONCLUSION

High intake of UPFs was linked with an enhanced IBD risk, a specific risk of CD. However, conducting more observational studies among several ethnicities and using specific tools that accurately assess the amount of UPF consumption, components of UPFs, and food additives may be necessary. Systematic Review Registration: PROSPERO registration no. CRD42023390258.

Role of diet in prevention versus treatment of Crohn's disease and ulcerative colitis

Diet is a modifiable risk factor for disease course and data over the past decade have emerged to indicate its role in Crohn's disease (CD) and ulcerative colitis (UC). However, literature is riddled with misinterpretation of data, often leading to unexpected or conflicting results. The key understanding is that causative factors in disease development do not always proceed to an opportunity to change disease course, once established. Here, we discuss the data on dietary influences in three distinct disease states for CD and UC-predisease, active disease and quiescent disease. We appraise the literature for how our dietary recommendations should be shaped to prevent disease development and if or how that differs for CD and UC induction therapy and maintenance therapy. In UC, principles of healthy eating are likely to play a role in all states of disease. Conversely, data linking dietary factors to CD prevention and treatment are paradoxical with the highest quality evidence for CD treatment being exclusive enteral nutrition, a lactose, gluten and fibre-free diet comprising solely of ultraprocessed food-all dietary factors that are not associated or inversely associated with CD prevention. High-quality evidence from dietary trials is much awaited to expand our understanding and ultimately lead our dietary recommendations for targeted patient populations.

Preventative and therapeutic potential of nutrition for inflammatory bowel diseases: A narrative review

Diet strongly shapes the gut microbiome and metabolome, which in turn influence intestinal inflammation in patients with inflammatory bowel disease (IBD). Separate from inflammation and malnutrition, diet's direct interactions with the gastrointestinal system can also provoke or attenuate a host of nonspecific gastrointestinal symptoms. Given these multifaceted effects of diet on inflammation and symptoms, nutrition has been investigated for its potential roles in the prevention and treatment of IBD. This review presents epidemiological, observational cohort, and clinical trial evidence that underlie our current understanding of nutrition for prevention and treatment of IBD.

Editorial: Unravelling the fibres-low dietary fibre may lower risk of developing IBD. Authors' reply

This article is linked to Deng et al papers. To view these articles, visit https://doi.org/10.1111/apt.17649 and https://doi.org/10.1111/apt.17663

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.

Higher dietary fibre intake is associated with lower risk of inflammatory bowel disease: prospective cohort study

BACKGROUND

Limited prospective studies that have examined the association of dietary fibre with IBD have provided inconsistent evidence.

AIM

To examine any associations between dietary fibre intake and subsequent incidence of IBD, Crohn's disease (CD) and ulcerative colitis (UC) METHODS: We conducted a prospective cohort study of 470,669 participants from the UK Biobank and estimated dietary fibre intake from a valid food frequency questionnaire at baseline. Incident IBD was ascertained from primary care data and inpatient data. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between dietary fibre intake and the risk of IBD, CD and UC.

RESULTS

During an average follow-up of 12.1 years, we ascertained 1473 incident IBD cases, including 543 cases of CD and 939 cases of UC. Comparing the lowest quintiles, an inverse association was observed between dietary fibre intake and risk of IBD (HR 0.74, 95% CI 0.58-0.93, p = 0.011) and CD (HR 0.48, 95% CI 0.32-0.72, p < 0.001), but not UC (HR 0.92, 95% CI 0.69-1.24, p = 0.595). For specified sources, dietary fibre intake from fruit and bread decreased the risk of CD, while dietary fibre intake from cereal decreased the risk of UC.

CONCLUSIONS

Higher consumption of dietary fibre was associated with a lower risk of IBD and CD, but not UC. Our findings support current recommendations to increase the intake of dietary fibre.

Food Processing and Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Several studies have been published on the association between food processing and risks of Crohn's disease (CD) and ulcerative colitis (UC), with some variability in results. We performed a systematic literature review and meta-analysis to study this association.

METHODS

From PubMed, Medline, and Embase until October 2022, we identified cohort studies that studied the association between food processing and the risk of CD or UC. Risk of bias of the included studies was assessed by the Newcastle-Ottawa scale. We computed pooled hazard ratios (HRs) and 95% confidence intervals (CIs) using random-effects meta-analysis based on estimates and standard errors.

RESULTS

A total of 1,068,425 participants were included (13,594,422 person-years) among 5 cohort studies published between 2020 and 2022. Four of the 5 included studies were scored as high quality. The average age of participants ranged from 43 to 56 years; 55%-83% were female. During follow-up, 916 participants developed CD, and 1934 developed UC. There was an increased risk for development of CD for participants with higher consumption of ultra-processed foods compared with those with lower consumption (HR, 1.71; 95% CI, 1.37-2.14; I2 = 0%) and a lower risk of CD for participants with higher consumption of unprocessed/minimally processed foods compared with those with lower consumption (HR, 0.71; 95% CI, 0.53-0.94; I2 = 11%). There was no association between risk of UC and ultra-processed foods (HR, 1.17; 95% CI, 0.86-1.61; I2 = 74%) or unprocessed/minimally processed foods (HR, 0.84; 95% CI, 0.68-1.02; I2 = 0%).

CONCLUSIONS

Higher ultra-processed food and lower unprocessed/minimally processed food intakes are associated with higher risk of CD but not UC.

Food Processing and Risk of Crohn's Disease and Ulcerative Colitis: A European Prospective Cohort Study

BACKGROUND & AIMS

Industrial foods have been associated with increased risks of several chronic conditions. We investigated the relationship between the degree of food processing and risks of Crohn's disease (CD) and ulcerative colitis (UC) in the European Prospective Investigation into Cancer and Nutrition cohort.

METHODS

Analyses included 413,590 participants (68.6% women; mean baseline age, 51.7 y) from 8 European countries. Dietary data were collected at baseline from validated country-specific dietary questionnaires. Associations between proportions of unprocessed/minimally processed and ultraprocessed food intake and CD and UC risks were estimated using Cox models to obtain hazard ratios (HRs) and 95% CIs. Models were stratified by center, age, and sex, and adjusted for smoking status, body mass index, physical activity, energy intake, educational level, and alcohol consumption.

RESULTS

During a mean follow-up period of 13.2 years, 179 incident cases of CD and 431 incident cases of UC were identified. The risk of CD was lower in people consuming high proportions of unprocessed/minimally processed foods (adjusted HR for the highest vs lowest quartile: 0.57; 95% CI, 0.35-0.93; P trend < .01), particularly fruits and vegetables (adjusted HRs, 0.54; 95% CI, 0.34-0.87 and 0.55; 95% CI, 0.34-0.91, respectively). There was no association between unprocessed/minimally processed food intake and the risk of UC. No association was detected between ultraprocessed food consumption and CD or UC risks.

CONCLUSIONS

In the European Prospective Investigation into Cancer and Nutrition cohort, consumption of unprocessed/minimally processed foods was associated with a lower risk of CD. No association between UC risk and food processing was found.

Impact of Dietary Patterns in Inflammatory Bowel Disease Subtypes Versus Healthy Subjects: a Retrospective Cohort Study

Objectives:Inflammatory bowel diseases (IBD) have been associated with multiple environmental factors, including diet. A dietary pattern characterized by low fiber content, high fat content and high carbohydrate content has been linked to the development of IBD. The objective of the current investigation is to examine the potential link between dietary patterns and the occurrence of IBD and to investigate whether there are any differences in relation to the type of IBD and specific food groups. Material and methods:We conducted an observational retrospective comparative study using three cohorts: 89 Crohn's disease (CD) patients, 40 ulcerative colitis (UC) patients and 64 healthy subjects. All participants underwent structured interviews and were required to complete a questionnaire regarding their dietary habits either prior to the onset of IBD or within the last year for control subjects. Results:A higher proportion of CD patients reported a higher rate of salt intake (71.9% vs. 53.1%, p-value = 0.043), sweetened beverages (38.2% vs. 17.2%, p-value=0.022), processed meat (66.3% vs. 40.6%, p-value=0.007), fatty meat (50.6% vs. 28.1%, p-value=0.021), fried foods (47.2% vs. 9.4%, p-value<0.001) and mayonnaise (21.3% vs. 6.2%, p-value=0.032) and a lower intake of nuts and seeds (20.2% vs. 43.8%, p-value=0.004) and yogurt (23.6% vs. 43.8%, p-value=0.030) compared to healthy subjects. Compared to controls, in the UC group there was a higher consumption of salt (85% vs. 53.1%, p-value=0.003), sweetened beverages (47.5% vs. 17.2%, p-value=0.005), fatty meat (55% vs. 28.1%, p-value=0.025) and fried foods (55% vs. 9.4%, p-value<0.001) and a lower intake of nuts and seeds (10% vs. 43.8%, p-value=0.001). Conclusion:Diet patterns before the onset of the disease are similar in patients with Crohn's disease and patients with ulcerative colitis: increased consumption of sweetened beverages, processed and fatty meat, fried food, salt, store-bought ice cream, and mayonnaise, and decreased intake of seeds, nuts, and yogurt.

Clinical characteristics of elderly-onset inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of chronic non-specific intestinal inflammatory diseases whose etiology has not been elucidated. The prevalence of elderly-onset IBD is increasing; however, its disease phenotype, pathophysiology, and clinical characteristics are different from those of adult-onset IBD. In order to better manage elderly IBD patients, it is becoming increasingly important to accurately describe the unique characteristics of elderly-onset IBD. Therefore, this article, based on the domestic and foreign literature reports from 2017 to now, describes the characteristics of elderly-onset IBD with regard to pathogenesis, epidemiological characteristics, clinical features, and treatment.

Diet Quality and Risk of Older-Onset Crohn's Disease and Ulcerative Colitis

BACKGROUND

To assess the relationship between diet quality and risk of older-onset Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We conducted a prospective cohort study of 83,147 participants from the Swedish Mammography Cohort and the Cohort of Swedish Men. We used food frequency questionnaire to calculate adherence scores to multiple derived health diet patterns: Alternate Healthy Eating Index (AHEI), Healthy Eating Index-2015 (HEI-2015), Healthful Plant-Based Diet Index (HPDI), and modified Mediterranean Diet Score (mMED) at baseline in 1997 in both cohorts. Diagnoses of CD and UC were retrieved from the Swedish Patient Register. We used Cox proportional hazards modeling to estimate the adjusted hazard ratios (HRs) and 95% CIs.

FINDINGS

Through December of 2017, we confirmed 164 incident cases of CD and 395 incident cases of UC. Comparing the highest to the lowest quartiles, the adjusted HRs of CD were 0.73 (95% CI, 0.48, 1.12, Ptrend = 0.123) for AHEI; 0.90 (0.57, 1.41, Ptrend = 0.736) for HEI 2015; 0.52 (95% CI 0.32, 0.85, Ptrend = 0.011) for HPDI; and 0.58 (95% CI 0.32, 1.06, Ptrend = 0.044) for mMED. In contrast, we did not observe an association between any diet quality score and risk of UC.

INTERPRETATION

We found that several healthy eating patterns were associated with a lower risk of older-onset CD. Our findings provide a rationale for adapting different healthy dietary patterns based on individuals' food preferences and traditions for designing future prevention strategies for IBD.

Selected Aspects of Nutrition in the Prevention and Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease has become a global health problem at the turn of the 21st century. The pathogenesis of this disorder has not been fully explained. In addition to non-modifiable genetic factors, a number of modifiable factors such as diet or gut microbiota have been identified. In this paper, the authors focus on the role of nutrition in the prevention of inflammatory bowel disease as well as on the available options to induce disease remission by means of dietary interventions such as exclusive and partial enteral nutrition in Crohn's disease, the efficacy of which is reported to be comparable to that of steroid therapy. Diet is also important in patients with inflammatory bowel disease in the remission stage, during which some patients report irritable bowel disease-like symptoms. In these patients, the effectiveness of diets restricting the intake of oligo-, di-, monosaccharides, and polyols is reported.

Dietary management of adults with IBD - the emerging role of dietary therapy

Historically, dietitians played a minor part in the management of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis. Patients were commonly referred for consequences of uncontrolled disease, such as malnutrition and bowel obstruction risk. Today, dietitians are fundamental members of the multidisciplinary IBD team, from educating on the role of diet at diagnosis and throughout the lifespan of a patient with IBD to guiding primary induction therapy. This aspect is reflected in published guidelines for IBD management, which previously placed diet as only a minor factor, but now have diet-specific publications. This Review describes a four-step approach in a dietitian's assessment and management of diet in patients with IBD: (1) identifying and correcting nutritional gaps and dietary imbalances; (2) considering diet to treat active disease with the use of exclusive enteral nutrition (EEN) or emerging diets that could replace EEN; (3) using therapeutic diets to control existing complications of IBD, such as reduced fibre to prevent bowel obstruction in stricturing disease or a fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet to manage co-existing functional gut symptoms; and (4) considering the role of diet in preventing IBD development in high-risk populations.

Mendelian randomization analysis reveals causal effects of food intakes on inflammatory bowel disease risk

Traditional observational studies have indicated a link between specific food intakes and inflammatory bowel disease (IBD), but the nature of such links remains unknown. We sought to assess the potential causal relationship between food intakes and IBD risk using Mendelian randomization methods. This study used summary statistics data from large-scale genome-wide association studies (GWAS) on food intakes, Crohn’s disease (CD), and ulcerative colitis (UC). In the primary analysis, we used the inverse variance-weighted method to determine whether specific food was causal for CD and UC. In addition, we also ran four other Mendelian randomization methods, including MR Egger, weighted median, maximum likelihood, and weighted mode as a complement. The primary analysis showed that high consumption of poultry (OR, 3.696; 95% CI, 1.056–12.937; p = 0.041) and cereal (OR, 2.449; 95% CI, 1.094–5.482; p = 0.029) had a significant causal association with CD, while high oily fish intake level was found to be statistically significantly associated with the risk of UC (OR, 1.482; 95% CI, 1.002–2.194; p = 0.049). This MR study provides evidence of a potential causal link between certain food intake and CD and UC.

Diets for inflammatory bowel disease: What do we know so far?

In recent years, the role of diet in the pathogenesis of inflammatory bowel disease (IBD) has gained great interest within the scientific community. Eating habits from industrialised countries (the so-called western diet or WD) have been associated with a higher incidence of IBD in observational studies, although the dietary factors responsible for the development of the disease are still to be elucidated. Some components of the diet with proinflammatory potential may cause changes in immunity and intestinal microbiota, leading to the inflammatory reaction that causes IBD-related lesions. The quality of available evidence is low, due to methodological issues, such as the lack of intervention studies, small sample size and heterogeneity of studies. For this reason, scientific societies have offered their recommendations using clinical practice guidelines and consensus documents, in order to establish a common criterion in the nutritional treatment of patients with IBD. The objective of this review was to summarise the data published regarding diet in IBD and review the recommendations given by scientific societies.

Meat Intake Is Associated with a Higher Risk of Ulcerative Colitis in a Large European Prospective Cohort Studyø

BACKGROUND AND AIMS

We aimed to investigate the association between protein intake and risk of inflammatory bowel disease [IBD] in the European Prospective Investigation into Cancer and Nutrition.

METHODS

A total of 413 593 participants from eight European countries were included. Dietary data were collected at baseline from validated food frequency questionnaires. Dietary data were calibrated to correct errors in measures related to each country-specific questionnaire. Associations between proteins [total, animal, and vegetable] or food sources of animal proteins, and IBD risk were estimated by Cox proportional hazard models.

RESULTS

After a mean follow-up of 16 years, 177 patients with Crohn's disease [CD] and 418 with ulcerative colitis [UC], were identified. There was no association between total protein, animal protein, or vegetable protein intakes and CD or UC risks. Total meat and red meat intakes were associated with UC risk (hazard ratio [HR] for the 4th vs 1st quartile = 1.40, 95% confidence interval [CI] = 0.99-1.98, p-trend = 0.01; and 1.61, 95% CI = 1.10-2.36, p-trend = 0.007, respectively]. There was no association between other food sources of animal protein [processed meat, fish, shellfish, eggs, poultry] and UC. We found no association between food sources of animal proteins and CD risk.

CONCLUSIONS

Meat and red meat consumptions are associated with higher risks of UC. These results support dietary counselling of low meat intake in people at high-risk of IBD.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Manipulation of Gut Microbiota as a Key Target for Crohn's Disease

Crohn's disease (CD) is an inflammatory bowel disease (IBD) sub-type characterized by transmural chronic inflammation of the gastrointestinal tract. Research indicates a complex CD etiology involving genetic predisposition and immune dysregulation in response to environmental triggers. The chronic mucosal inflammation has been associated with a dysregulated state, or dysbiosis, of the gut microbiome (bacteria), mycobiome (fungi), virome (bacteriophages and viruses), and archeaome (archaea) further affecting the interkingdom syntrophic relationships and host metabolism. Microbiota dysbiosis in CD is largely described by an increase in facultative anaerobic pathobionts at the expense of strict anaerobic Firmicutes, such as Faecalibacterium prausnitzii. In the mycobiome, reduced fungal diversity and fungal-bacteria interactions, along with a significantly increased abundance of Candida spp. and a decrease in Saccharomyces cerevisiae are well documented. Virome analysis also indicates a significant decrease in phage diversity, but an overall increase in phages infecting bacterial groups associated with intestinal inflammation. Finally, an increase in methanogenic archaea such as Methanosphaera stadtmanae exhibits high immunogenic potential and is associated with CD etiology. Common anti-inflammatory medications used in CD management (amino-salicylates, immunomodulators, and biologics) could also directly or indirectly affect the gut microbiome in CD. Other medications often used concomitantly in IBD, such as antibiotics, antidepressants, oral contraceptives, opioids, and proton pump inhibitors, have shown to alter the gut microbiota and account for increased susceptibility to disease onset or worsening of disease progression. In contrast, some environmental modifications through alternative therapies including fecal microbiota transplant (FMT), diet and dietary supplements with prebiotics, probiotics, and synbiotics have shown potential protective effects by reversing microbiota dysbiosis or by directly promoting beneficial microbes, together with minimal long-term adverse effects. In this review, we discuss the different approaches to modulating the global consortium of bacteria, fungi, viruses, and archaea in patients with CD through therapies that include antibiotics, probiotics, prebiotics, synbiotics, personalized diets, and FMT. We hope to provide evidence to encourage clinicians and researchers to incorporate these therapies into CD treatment options, along with making them aware of the limitations of these therapies, and indicate where more research is needed.

Dietary soybeans worsen dextran sodium sulfate-induced colitis by disrupting intestinal ecology

Food mediates susceptibility to inflammatory bowel diseases (IBDs) associated with the microbiome. Existing studies suggest that a high-sugar and high-fat diet promotes IBDs, but whether a plant-based diet is fully harmless to IBD improvement remains unknown. In this study, for the first time, we assessed the effect of soybean and its carbohydrates on dextran sodium sulfate (DSS)-induced colitis. In a DSS-induced colitis mouse model (BALB/C WT), the oral administration of soybeans worsened colitis, which was associated with higher disease activity index, histology score and expression of pro-inflammatory cytokines, and lower expression of anti-inflammatory cytokines. Here, 16S rRNA sequencing and elimination of gut bacteria by antibiotics showed that the exacerbating colitis caused by soybeans depends on the changes in the intestinal flora. Furthermore, the gavage of soybean carbohydrates such as sucrose and raffinose-family oligosaccharides altered the intestinal microbiota and worsened inflammation. When co-cultured with macrophages (RAW 264.7), the metabolites of the disordered intestinal flora, isolated Escherichia coli and purified LPS showed high macrophage toxicity to inhibit pathogen clearance. These results indicate that the intake of soybeans and soybean carbohydrates is not conducive to recovery from IBDs based on changes in gut microbiota and metabolites affecting the activities of macrophages.

Ultra-processed Foods and Risk of Crohn's Disease and Ulcerative Colitis: A Prospective Cohort Study

BACKGROUND & AIMS

The rising incidence of inflammatory bowel disease in regions undergoing Westernization has coincided with the increase in ultra-processed food (UPF) consumption over the past few decades. We aimed to examine the association between consumption of UPFs and the risk of Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We performed a prospective cohort study of 3 nationwide cohorts of health professionals in the United States-the Nurses' Health Study (1986-2014), the Nurses' Health Study II (1991-2017), and the Health Professionals Follow-up Study (1986-2012). We employed Cox proportional hazards models with adjustment for confounders to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for CD and UC according to self-reported consumption of UPFs.

RESULTS

The study included 245,112 participants. Over 5,468,444 person-years of follow-up, we documented 369 incident cases of CD and 488 incident cases of UC. The median age at diagnosis was 56 years (range, 29-85 years). Compared with participants in the lowest quartile of simple updated UPF consumption, those in the highest quartile had a significantly increased risk of CD (HR, 1.70; 95% CI, 1.23-2.35; P_trend = .0008). Among different UPF subgroups, ultra-processed breads and breakfast foods; frozen or shelf-stable ready-to-eat/heat meals; and sauces, cheeses, spreads, and gravies showed the strongest positive associations with CD risk (HR per 1 standard deviation increase in intake, 1.18 [95% CI, 1.07-1.29], 1.11 [95% CI, 1.01-1.22], and 1.14 [95% CI, 1.02-1.27], respectively). There was no consistent association between UPF intake and UC risk.

CONCLUSIONS

Higher UPF intake was associated with an increased risk of incident CD. Further studies are needed to identify specific contributory dietary components.

Microbiome-based interventions to modulate gut ecology and the immune system

The gut microbiome lies at the intersection between the environment and the host, with the ability to modify host responses to disease-relevant exposures and stimuli. This is evident in how enteric microbes interact with the immune system, e.g., supporting immune maturation in early life, affecting drug efficacy via modulation of immune responses, or influencing development of immune cell populations and their mediators. Many factors modulate gut ecosystem dynamics during daily life and we are just beginning to realise the therapeutic and prophylactic potential of microbiome-based interventions. These approaches vary in application, goal, and mechanisms of action. Some modify the entire community, such as nutritional approaches or faecal microbiota transplantation, while others, such as phage therapy, probiotics, and prebiotics, target specific taxa or strains. In this review, we assessed the experimental evidence for microbiome-based interventions, with a particular focus on their clinical relevance, ecological effects, and modulation of the immune system.

Health Benefits of Dietary Fiber for the Management of Inflammatory Bowel Disease

Crohn's disease (CD) and ulcerative colitis (UC), two components of inflammatory bowel disease (IBD), are painful conditions that affect children and adults. Despite substantial research, there is no permanent cure for IBD, and patients face an increased risk of colon cancer. Dietary fiber's health advantages have been thoroughly investigated, and it is recommended for its enormous health benefits. This review article discusses the importance of appropriate fiber intake in managing IBD, emphasizing how optimal fiber consumption can significantly help IBD patients.

Mediterranean diet diminishes the effects of Crohn's disease and improves its parameters: A systematic review

BACKGROUND

The pathogenesis and clinical course of Crohn's disease (CD) is influenced by diet. Mediterranean Diet (MD) helps Crohn's patients through many mechanisms.

AIMS

This study aimed to evaluate the effect of the MD on CD patients and to evaluate such effect on body parameters.

METHODS

PubMed, Science Direct, Web of Science, MEDLINE and Cochrane central library were searched for MD and CD from 2010 to 2020. Included studies met the following criteria: (1) male and female adults (18-75 years) with a confirmed diagnosis of CD; (2) MD as an intervention; (3) original interventional Trial, Cross-Sectional Analysis, or Prospective Cohort Studies.

RESULTS

Five studies were included, involving 83,564 participants. A small number of patients with CD fulfilled the P-MDS criteria, the overall scores were low, 4.7 and 4.5 for females and males respectively. Patients with an inactive disease whose adherence to MD was greater, the MD score was negatively correlated with disease activity (p <0.001) and positively with IBDQ (p = 0.008). Twenty-seven percent had a prevalence of impaired adherence to a MD (mMED score = 0-2), giving such a population a risk attributed to 12% for the later CD. Seventy-point reduction in CDAI + decreased fecal CRP / calprotectin, calprotectin <250 mcg/gm or >50% decrease from baseline and hsCRP < 5 mg/L or >50% from baseline.

CONCLUSIONS

MD showed anti-inflammatory properties. Adherence to MD was associated with improvement in CD patients and negatively correlated with the disease activity, in addition to a lower risk of developing CD later in life.

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.

Reducing Disease Activity of Inflammatory Bowel Disease by Consumption of Plant-Based Foods and Nutrients

Inflammatory bowel disease is a chronic and recurring inflammatory condition of the gastrointestinal tract encompassing ulcerative colitis and Crohn's disease. Although the pathogenesis of inflammatory bowel disease remains to be fully elucidated, environmental factors such as diet are believed to play a pivotal role in the onset and management of inflammatory bowel disease. Diet is thought to play an essential role in intestinal inflammation due to its regulatory effects on the microbiota, gut immune system, and epithelial barrier function. Although the evidence remains insufficient to draw firm conclusions on the role of specific dietary components in gastrointestinal diseases, studies have suggested that a Western diet with high intakes of total fats, omega-6 fatty acids, and meat have been associated with intestinal inflammation and relapse of inflammatory bowel disease. In contrast to a Western diet, plant-based diets often result in a reduced intake of total fats and meats and an increased intake of plant fibers which may contribute to reduced intestinal inflammation. This review critically examines the influence of plant-based dietary components on the clinical disease course of inflammatory bowel disease. Furthermore, this review discusses the benefits and possible limitations of plant-derived dietary components in the treatment of inflammatory bowel disease while addressing the principal type of disease and the anatomic site of inflammation within the gastrointestinal tract. Finally, this review points out important directions for future research on the role of diet in inflammatory bowel disease. A better understanding of the role of diet and intestinal inflammation may pave the way for novel dietary interventions and specific foods- or food supplements, which can support the treatment of inflammatory bowel disease.

Leveraging diet to engineer the gut microbiome

Autoimmune diseases, including inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, have distinct clinical presentations but share underlying patterns of gut microbiome perturbation and intestinal barrier dysfunction. Their potentially common microbial drivers advocate for treatment strategies aimed at restoring appropriate microbiome function, but individual variation in host factors makes a uniform approach unlikely. In this Perspective, we consolidate knowledge on diet-microbiome interactions in local inflammation, gut microbiota imbalance and host immune dysregulation. By understanding and incorporating the effects of individual dietary components on microbial metabolic output and host physiology, we examine the potential for diet-based therapies for autoimmune disease prevention and treatment. We also discuss tools targeting the gut microbiome, such as faecal microbiota transplantation, probiotics and orthogonal niche engineering, which could be optimized using custom dietary interventions. These approaches highlight paths towards leveraging diet for precise engineering of the gut microbiome at a time of increasing autoimmune disease.

Results of the Seventh Scientific Workshop of ECCO: Precision Medicine in IBD-Prediction and Prevention of Inflammatory Bowel Disease

Inflammatory bowel disease [IBD] is a complex chronic disorder with no clear aetiology and no known cure. Despite recent advances in overall disease management and improved therapeutics, patients with IBD still experience a substantial burden. Furthermore, as the incidence continues to increase in developing areas of the world, it is expected that the burden of IBD to society will increase and exert tremendous pressure on health care systems worldwide. Therefore, new strategies to prevent the global increase of IBD are urgently required. Data are being progressively acquired on the period preceding disease diagnosis, which support the concept that IBD has a preclinical period that may reveal the triggers of disease and may be amenable to early intervention. Having a better knowledge of this preclinical period will increase the potential not only for improved understanding of disease pathogenesis and improved therapeutics, but also for disease prediction and prevention.

Diet as an environmental trigger in inflammatory bowel disease: a retrospective comparative study in two European cohorts

BACKGROUND AND AIMS

inflammatory bowel disease development has been associated with several environmental factors, among which, diet can play a key role, probably due to a westernized lifestyle. However, its involvement in the pathogenesis of inflammatory bowel disease (IBD) is difficult to demonstrate. The aim of this study was to analyze dietary composition in a Romanian and Belgian population with IBD.

METHODS

an observational retrospective comparative study was performed using two European cohorts (Romanian and Belgian). The IBD group included 76 Romanian and 53 Belgian patients with an IBD diagnosis, while the control group included a total of 56 healthy people (35 Romanians and 21 Belgians). All subjects were interviewed and asked to fill in a questionnaire regarding diet.

RESULTS

in the entire IBD cohort (Romanian + Belgian), a significantly increased consumption of sweets (OR 3.36 [95 % CI 1.6,7]), processed and high fat meat (OR 2.5 [95 % CI 1.4, 4.7], fried food (OR 9.5 [3.8, 23.6]), salt (OR 2.8 [1.5, 5.3]), ice cream (OR 3.25 [1.1, 9.8]), mayonnaise (OR 3.49 [1.1, 10.3]), margarine (OR 5.63 [1.64, 19.33]) and chips/nachos/other snacks (OR 2.3 [0.97, 5.73]) were found compared to the healthy control group. The intake of seeds, nuts (OR 0.26 [0.14, 0.52]) and yoghurt consumption (OR 0.44 [0.23, 0.83]) was lower in the IBD group compared to the control group.

CONCLUSION

a westernized diet with increased consumption of sweets, processed food, high fat meat, fried food, salt, margarine, snacks, ice cream and mayonnaise seems to be a risk factor for IBD in Romanian and Belgian IBD patients. Intake of seeds, nuts and yoghurt may be a protective factor.

Current recommendations on the role of diet in the aetiology and management of IBD

Diet is a key modifier of risk of inflammatory bowel disease development and potentially a treatment option in patients with established disease. International organisations in gastroenterology and inflammatory bowel disease have published guidelines for the role of diet in disease onset and its management. Here, we discuss the major overarching themes arising from these guidelines and appraise recent literature on the role of diet for inflammatory bowel disease prevention, treatment of active disease and maintenance of remission, considering these themes. Except for exclusive enteral nutrition in active Crohn's disease, we currently possess very little evidence to make any further dietary recommendations for the management of inflammatory bowel disease. There is also currently uncertainty on the extrapolation of epidemiological dietary signals on risk of disease development and preclinical experiments in animal models to management, once disease is established. Until high-quality evidence from clinical research becomes available, the only specific recommendations for inflammatory bowel disease we might safely give are those of healthy eating which apply for the general population for overall health and well-being.

Food-related quality of life in adults with inflammatory bowel disease is associated with restrictive eating behaviour, disease activity and surgery: A prospective multicentre observational study

BACKGROUND

Measuring food-related quality of life (FRQoL) quantifies the psychosocial impact of eating and drinking. FRQoL and associated factors are not well explored in people with inflammatory bowel disease (IBD), despite IBD being a chronic disease affecting the digestive tract. The present study aimed to characterise and identify any patient or disease-related predictors of FRQoL in individuals with IBD.

METHODS

Adults with a formal diagnosis of IBD were recruited to a prospective multicentre cross-sectional study between April 2018 and December 2019. Participants completed questionnaires measuring FRQoL (FRQoL-29), clinical disease activity (Harvey Bradshaw Index and Simple Clinical Colitis Activity Index), restrictive eating behaviour (Nine-Item Avoidant/Restrictive Food Intake Disorder Screen), mental health (Depression Anxiety Stress Scale-21) and other patient and disease-related variables. A multivariable regression was performed to identify factors associated with FRQoL.

RESULTS

One hundred and eight participants completed the questionnaires (n = 39, Crohn's disease; n = 69, ulcerative colitis). The mean FRQoL was 79 (95% confidence interval = 75-84) (poor, 0; superior, 145). Poorer FRQoL was observed in those with restrictive eating behaviour associated with fear of a negative consequence from eating (p < 0.0001) and reduced appetite (p < 0.030). Greater FRQoL was observed in those with lower disease activity (p < 0.0001) and previous IBD surgery (p = 0.024). FRQoL was not associated either way by IBD phenotype, duration, or gender. The majority of participants obtained their dietary information from the internet (60%) or gastroenterologist (46%).

CONCLUSIONS

FRQoL in people with IBD is poorer in those with restrictive eating behaviours and clinically active disease. Interestingly, it was greater in those with previous IBD surgery. Further research is required to validate these associations and explore longitudinal effects of poor FRQoL on patient outcomes and potential strategies for prevention or management of impaired FRQoL in IBD.

Inflammatory Bowel Diseases: Is There a Role for Nutritional Suggestions?

Nutrition has an important impact on inflammatory bowel diseases (IBD). In particular, several studies have addressed its role in their pathogenesis, showing how the incidence of IBD significantly increased in recent years. Meanwhile, nutrition should be considered a component of the treatment of the disease, both as a therapy itself, and especially in the perspective of correcting the various nutritional deficiencies shown by these patients. In this perspective, nutritional suggestions are very important even in the most severe forms of IBD, requiring hospitalization or surgical treatment. Although current knowledge about nutrition in IBD is increasing over time, nutritional suggestions are often underestimated by clinicians. This narrative review is an update summary of current knowledge on nutritional suggestions in IBD, in order to address the impact of nutrition on pathogenesis, micro- and macro-nutrients deficiencies (especially in the case of sarcopenia and obesity), as well as in hospitalized patients.

Perception of the Role of Food and Dietary Modifications in Patients with Inflammatory Bowel Disease: Impact on Lifestyle

BACKGROUND

Diet has a relevant role in triggering symptoms in inflammatory bowel disease (IBD) from the patients' perspective, but there is gap the between patients' and doctors' perceptions. Few studies have addressed this topic. The aim of this study was to evaluate food habits and nutrition knowledge in a homogeneous cohort of patients with IBD from southern Italy.

METHODS

167 consecutive patients with IBD were recruited. The survey was based on the administration of a semi-structured questionnaire assessing demographics, disease features, dietary behavior, and food intolerance.

RESULTS

The majority of patients did not consider food a cause of their disease. However more than 80% changed their diet after the diagnosis and most report an improvement in symptoms. Spiced and seasoned foods, dairy products, vegetables, and fruit were often avoided. A dairy-free diet was adopted by 33.7%. Food choices were based on self-experience and not on medical counselling. Dietary modifications deeply impact on lifestyle.

CONCLUSIONS

Most of the patients with IBD set diet and lifestyle on self-experience and give up many foods. This has an impact on psychosocial functioning and can lead to nutritional deficiencies. High quality studies are warranted to assess evidence-based dietary strategies and develop patient-targeted dietary recommendations.

Fibrotic Strictures in Crohn's Disease: Mechanisms and Predictive Factors

Fibrotic strictures are one of the most severe complications of Crohn's Disease (CD). They occur in about 50% of patients at five years and in 70% at ten years of the diagnosis. The only treatment available for symptomatic fibrotic strictures is surgical resection and endoscopic dilation. Both strategies are associated with a high rate of recurrence, and with multiple surgical resections, which pose the threat of surgical morbidity and short bowel syndrome. Therefore, it is crucial to identify, early, the patients more prone to develop intestinal fibrosis to intensify follow-ups, switch to more aggressive treatments, and suggest lifestyle modifications. Scarce data are available concerning biomarkers and genetic determinants to predict which patient will develop intestinal fibrosis. Biologic or clinical markers would be useful to determine this subgroup of CD patients and to predict the onset of intestinal fibrosis and, ideally, its severity. Furthermore, the identification of environmental risk factors may suggest lifestyle changes aimed at modifying the natural course, thus decreasing the risk of complicated CD. In this review, we will critically revise clinical, environmental, genetic, and serologic factors that have been associated with a complicated CD course with a particular focus on the fibrostenosing phenotype and their possible implications as predictive factors of intestinal fibrosis.

Dietary fibre in gastrointestinal health and disease

Epidemiological studies have consistently demonstrated the benefits of dietary fibre on gastrointestinal health through consumption of unrefined whole foods, such as wholegrains, legumes, vegetables and fruits. Mechanistic studies and clinical trials on isolated and extracted fibres have demonstrated promising regulatory effects on the gut (for example, digestion and absorption, transit time, stool formation) and microbial effects (changes in gut microbiota composition and fermentation metabolites) that have important implications for gastrointestinal disorders. In this Review, we detail the major physicochemical properties and functional characteristics of dietary fibres, the importance of dietary fibres and current evidence for their use in the management of gastrointestinal disorders. It is now well-established that the physicochemical properties of different dietary fibres (such as solubility, viscosity and fermentability) vary greatly depending on their origin and processing and are important determinants of their functional characteristics and clinical utility. Although progress in understanding these relationships has uncovered potential therapeutic opportunities for dietary fibres, many clinical questions remain unanswered such as clarity on the optimal dose, type and source of fibre required in both the management of clinical symptoms and the prevention of gastrointestinal disorders. The use of novel fibres and/or the co-administration of fibres is an additional therapeutic approach yet to be extensively investigated.

The Adequacy of Habitual Dietary Fiber Intake in Individuals With Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

Dietary fiber may influence disease course in individuals with inflammatory bowel disease (IBD), yet there is a paucity of understanding of habitual fiber intakes.

OBJECTIVES

To identify studies measuring fiber intakes of individuals with IBD, compare the adequacy of fiber intakes with that of control groups or respective national dietary guidelines, and examine factors associated with fiber consumption.

METHODS

Five electronic databases-MEDLINE, CINAHL, SCOPUS, PROQUEST, and COCHRANE LIBRARY-were systematically searched, using search terms inflammatory bowel disease, Crohn's disease, ulcerative colitis, dietary intake, and fiber, until December 2019, with hand searching of reference lists. Primary studies were included if fiber intakes were measured in participants 18 years of age or older, with confirmed IBD, with or without comparison to a control.

RESULTS

A total of 2105 publications were identified, and 26 met inclusion criteria. Total fiber intake of 4164 participants with IBD ranged broadly (9.9 ± 7.8 g/day to 21.0 ± 10.5 g/day). Most (18/26) used cross-sectional study design, with a large degree of heterogeneity in tools measuring fiber intake. Sixty-six percent of studies comparing participants with IBD with control groups found that participants with IBD consumed significantly less fiber than control subjects. Four studies reported that less than 10% to 21% of IBD participants met their national fiber recommendations. Data conflicted regarding an association between disease type, disease activity, or rate of relapse and fiber intake.

CONCLUSIONS

Individuals with IBD consume less fiber than healthy populations. Fiber intakes are inadequate compared with respective national fiber guidelines. Interpretation of factors associated with fiber intakes were limited by data quality and conflicting results. Future research is required into factors associated with fiber intake and whether increasing fiber intakes can influence disease course and behavior.

Role of diet and nutrition in inflammatory bowel disease

Inflammatory bowel diseases (IBDs) are closely linked to nutrition. The latest research indicates that diet and nutrition are significantly involved in the etiopathogenesis of the disease, although their specific role throughout its clinical course still remains unclear. This study reviewed how diet and nutrition are associated with IBD development and management. Even though specific diets have been shown to bring about positive outcomes, there is currently no scientific consensus regarding an appropriate diet that would benefit all IBD patients. We suggest that individualized dietary recommendations are of the greatest importance and that diets should be planned to provide individual IBD patients with specific nutrient requirements while keeping all the clinical aspects of the patients in mind. Further research is clearly necessary to investigate nutritional factors involved in IBD development and, especially, to evaluate the applications of the diets during the course of the disease.

Not All Fibers Are Born Equal; Variable Response to Dietary Fiber Subtypes in IBD

Diet provides a safe and attractive alternative to available treatment options in a variety of diseases; however, research has only just begun to elucidate the role of diet in chronic diseases, such as the inflammatory bowel diseases (IBD). The chronic and highly debilitating IBDs, Crohn disease and ulcerative colitis, are hallmarked by intestinal inflammation, immune dysregulation, and dysbiosis; and evidence supports a role for genetics, microbiota, and the environment, including diet, in disease pathogenesis. This is true especially in children with IBD, where diet-based treatments have shown excellent results. One interesting group of dietary factors that readily links microbiota to gut health is dietary fibers. Fibers are not digested by human cells, but rather fermented by the gut microbes within the bowel. Evidence has been mounting over the last decade in support of the importance of dietary fibers in the maintenance of gut health and in IBD; however, more recent studies highlight the complexity of this interaction and importance of understanding the role of each individual dietary fiber subtype, especially during disease. There are roughly ten subtypes of dietary fibers described to date, categorized as soluble or insoluble, with varying chemical structures, and large differences in their fermentation profiles. Many studies to date have described the benefits of the byproducts of fermentation in healthy individuals and the potential health benefits in select disease models. However, there remains a void in our understanding of how each of these individual fibers affect human health in dysbiotic settings where appropriate fermentation may not be achieved. This review highlights the possibilities for better defining the role of individual dietary fibers for use in regulating inflammation in IBD.

The Role of Diet in the Pathogenesis and Management of Inflammatory Bowel Disease: A Review

Inflammatory bowel diseases, which include ulcerative colitis and Crohn’s disease, are chronic relapsing and remitting inflammatory diseases of the gastrointestinal tract that are increasing in prevalence and incidence globally. They are associated with significant morbidity, reduced quality of life to individual sufferers and are an increasing burden on society through direct and indirect costs. Current treatment strategies rely on immunosuppression, which, while effective, is associated with adverse events. Epidemiological evidence suggests that diet impacts the risk of developing IBD and modulates disease activity. Using diet as a therapeutic option is attractive to patients and clinicians alike due to its availability, low cost and few side effects. Diet may influence IBD risk and disease behaviour through several mechanisms. Firstly, some components of the diet influence microbiota structure and function with downstream effects on immune activity. Secondly, dietary components act to alter the structure and permeability of the mucosal barrier, and lastly dietary elements may have direct interactions with components of the immune response. This review will summarise the mechanisms of diet–microbial–immune system interaction, outline key studies examining associations between diet and IBD and evidence demonstrating the impact of diet on disease control. Finally, this review will outline current prescribed dietary therapies for active CD.

Epidemiology and Pathogenesis of Ulcerative Colitis

Ulcerative colitis (UC) is a complex chronic, immune-mediated inflammatory disorder of the colon. Factors associated with increased risk of UC include diet, particularly Western diet influences in newly industrialized nations, medications, and lifestyle factors that may influence the host's microbiome or immune response to antigens. Although much evidence identifying potential genetic and host-related factors is currently available, there are still many unanswered questions. As the global UC incidence and prevalence continues to increase, there are multiple opportunities for continued investigation to clarify our understanding of UC, identify potential predictors of disease severity, response to therapy, and novel therapeutic targets.

Association of Dietary Fiber, Fruit, and Vegetable Consumption with Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

No previous investigation has summarized findings from prospective cohort studies on the association between dietary intake of fiber, fruit, and vegetables and risk of inflammatory bowel disease (IBD). Dietary fiber and its major sources can influence the risk of IBD by modulation of the gut microbiota. This study summarizes findings from published cohort studies on the association between dietary fiber, fruit, and vegetable consumption and risk of IBD. Relevant articles published up to January 2019 were searched via PubMed, MEDLINE, Scopus, Embase, Cochrane Library, and Google Scholar. All prospective cohort studies investigating the association between dietary fiber, fruit, and vegetable intake and risk of IBD were included. Combining 7 effect sizes from 6 studies, no significant association was found between dietary intake of fiber and risk of ulcerative colitis (UC) (RR: 1.09; 95% CI: 0.88, 1.34). However, a significant inverse association was found between dietary fiber intake and risk of Crohn disease (CD) (RR: 0.59; 95% CI: 0.46, 0.74), based on 5 studies with 6 effect sizes. Pooling information from 4 studies, we found a significant protective association between dietary intake of fruit and risk of UC (RR: 0.69; 95% CI: 0.55, 0.86) and CD (RR: 0.47; 95% CI: 0.38, 0.58). We also found a significant inverse association between vegetable consumption and risk of UC (RR: 0.56; 95% CI: 0.48, 0.66) and CD (RR: 0.52; 95% CI: 0.46, 0.59). In conclusion, dietary intake of fruit and vegetables was inversely associated with risk of IBD and its subtypes. Dietary fiber intake was also inversely associated with incidence of IBD and CD, but not with UC. Further studies are warranted to examine the association of other fiber-rich foods with IBD.

Dietary Fibre from Whole Grains and Their Benefits on Metabolic Health

The consumption of whole grain products is often related to beneficial effects on consumer health. Dietary fibre is an important component present in whole grains and is believed to be (at least partially) responsible for these health benefits. The dietary fibre composition of whole grains is very distinct over different grains. Whole grains of cereals and pseudo-cereals are rich in both soluble and insoluble functional dietary fibre that can be largely classified as e.g., cellulose, arabinoxylan, β-glucan, xyloglucan and fructan. However, even though the health benefits associated with the consumption of dietary fibre are well known to scientists, producers and consumers, the consumption of dietary fibre and whole grains around the world is substantially lower than the recommended levels. This review will discuss the types of dietary fibre commonly found in cereals and pseudo-cereals, their nutritional significance and health benefits observed in animal and human studies.

The Role of Epidemiological Evidence from Prospective Population Studies in Shaping Dietary Approaches to Therapy in Crohn's Disease

SCOPE

The concept that dietary factors are key risk and preventive agents in the development of Crohn's disease (CD), while widely believed and supported by epidemiological evidence, has yet to lead to clear identification of those factors through clinical trials. The aims are to examine the strength of the epidemiological evidence of diet and its association with CD, examine how interpretation of mostly epidemiological data has shaped ideas for potential dietary therapies, and to explore other factors that have driven the design of dietary clinical trials in CD.

METHODS

A literature search is performed in PubMed, Medline, EMBASE, and Google Scholar for prospective cohort studies and randomized clinical trials (RCTs) using search terms-"Crohn's disease," "diet," "risk," "remission," "treat," "cohort," "randomised."

RESULTS

Only four prospective cohort studies examine the relationship of diet and CD development, but these trials have been largely ignored by dietary RCTs in CD, which have used predominantly exclusion diets in small populations without objective endpoint assessment. Only one demonstrated clinical benefit to intestinal inflammation.

CONCLUSION

Investment in large multicenter dietary clinical trials that focus on dietary inclusions with objective endpoint assessment are needed to provide safe, sustainable dietary therapy to patients with CD.

Crohn's Disease: Is the Cold Chain Hypothesis Still Hot?

Crohn's disease [CD] is an inflammatory bowel disease of unknown aetiology. During recent decades, significant technological advances led to development of -omic datasets allowing a detailed description of the disease. Unfortunately these have not, to date, resolved the question of the aetiology of CD. Thus, it may be necessary to [re]consider hypothesis-driven approaches to resolve the aetiology of CD. According to the cold chain hypothesis, the development of industrial and domestic refrigeration has led to frequent exposure of human populations to bacteria capable of growing in the cold. These bacteria, at low levels of exposure, particularly those of the genus Yersinia, are believed to be capable of inducing exacerbated inflammation of the intestine in genetically predisposed subjects. We discuss the consistency of this working hypothesis in light of recent data from epidemiological, clinical, pathological, microbiological, and molecular studies.

Adherence to a Mediterranean diet is associated with a lower risk of later-onset Crohn's disease: results from two large prospective cohort studies

OBJECTIVE

To examine the relationship between Mediterranean diet and risk of later-onset Crohn's disease (CD) or ulcerative colitis (UC).

DESIGN

We conducted a prospective cohort study of 83 147 participants (age range: 45-79 years) enrolled in the Cohort of Swedish Men and Swedish Mammography Cohort. A validated food frequency questionnaire was used to calculate an adherence score to a modified Mediterranean diet (mMED) at baseline in 1997. Incident diagnoses of CD and UC were ascertained from the Swedish Patient Register. We used Cox proportional hazards modelling to calculate HRs and 95% CI.

RESULTS

Through December of 2017, we confirmed 164 incident cases of CD and 395 incident cases of UC with an average follow-up of 17 years. Higher mMED score was associated with a lower risk of CD (P_trend=0.03) but not UC (P_trend=0.61). Compared with participants in the lowest category of mMED score (0-2), there was a statistically significant lower risk of CD (HR=0.42, 95% CI 0.22 to 0.80) but not UC (HR=1.08, 95% CI 0.74 to 1.58). These associations were not modified by age, sex, education level, body mass index or smoking (all P_interaction >0.30). The prevalence of poor adherence to a Mediterranean diet (mMED score=0-2) was 27% in our cohorts, conferring a population attributable risk of 12% for later-onset CD.

CONCLUSION

In two prospective studies, greater adherence to a Mediterranean diet was associated with a significantly lower risk of later-onset CD.

Opening a Window on Attention: Adjuvant Therapies for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), most commonly known as Crohn's disease (CD) and ulcerative disease (UC), is a chronic and relapsing intestinal disease which cannot be cured completely. The prevalence of IBD in Europe and in North America has increased over the past 20 years. As most IBD patients are young at onset, their quality of life (QOL) can be influenced to varying degrees. Thus, current treatment goals are typically focused on preventing complications, including maintaining clinical remission and improving the QOL. Adjuvant therapies have been widely concerned as an effective treatment in alleviating IBD symptoms, including dietary intervention, traditional Chinese medicine, smoking, alcohol, and physical activities. This review focuses on different ancillary therapies for IBD treatments, in particular the mechanism of reducing inflammation based on the actual data from research studies. Moreover, comparing the latest data, this review also presented potential future prospect for adjuvant therapies.

Dietary Strategies for Maintenance of Clinical Remission in Inflammatory Bowel Diseases: Are We There Yet?

The etiopathogenesis of Inflammatory bowel disease (IBD) is a result of a complex interaction between host immune response, the gut microbiome and environmental factors, such as diet. Although scientific advances, with the use of biological medications, have revolutionized IBD treatment, the challenge for maintaining clinical remission and delaying clinical relapse is still present. As exclusive enteral nutrition has become a well-established treatment for the induction of remission in pediatric Crohn's disease, the scientific interest regarding diet in IBD is now focused on the development of follow-on dietary strategies, which aim to suppress colonic inflammation and delay a disease flare. The objective of this review is to present an extensive overview of the dietary strategies, which have been used in the literature to maintain clinical remission in both Crohn's disease and Ulcerative colitis, and the evidence surrounding the association of dietary components with clinical relapse. We also aim to provide study-related recommendations to be encompassed in future research studies aiming to investigate the role of diet during remission periods in IBD.

Dietary Guidance From the International Organization for the Study of Inflammatory Bowel Diseases

Recent evidence points to a plausible role of diet and the microbiome in the pathogenesis of both Crohn's disease (CD) and Ulcerative Colitis (UC). Dietary therapies based on exclusion of table foods and replacement with nutritional formulas and/or a combination of nutritional formulas and specific table foods may induce remission in CD. In UC, specific dietary components have also been associated with flare of disease. While evidence of varying quality has identified potential harmful or beneficial dietary components, physicians and patients at the present time do not have guidance as to which foods are safe, may be protective or deleterious for these diseases. The current document has been compiled by the nutrition cluster of the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) based on the best current evidence to provide expert opinion regarding specific dietary components, food groups and food additives that may be prudent to increase or decrease in the diet of patients with inflammatory bowel diseases to control and prevent relapse of inflammatory bowel diseases.