Review article: the association of diet with onset and relapse in patients with inflammatory bowel disease

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.

Association between dietary calcium to Phosphorus Ratio and the odds of ulcerative colitis: A case-control study

Background & aims

Ulcerative colitis (UC) is a recurrent, inflammatory, autoimmune intestinal disease. The dietary calcium to phosphorus (Ca:P) ratio is suggested to affect the inividuals' normal metabolic and inflammatory pathways. The present study aimed to investigate the association between dietary Ca:P ratio and the odds of developing UC in a case-control format.

Methods

The study included sixty-two currently diagnosed UC patients and one hundred twenty-four matched controls, designed as a case-control study. The dietary intakes of the participants were assessed by a food frequency questionnaire (FFQ), and the dietary Ca:P ratio was calculated. The association between tertiles of Ca:P ratio and UC was examined using the logistic regression. P-values <0.05 were considered as significant.

Results

The study sample consisted of participants with an average age of 36.63 ± 12.42 years and a mean body mass index (BMI) of 25.39 ± 3.82 kg/m2. The overall energy-adjusted ratio of Ca:P was 0.74 ± 0.11. In the multivariate model, after adjustment for potential confounders, participants in the third tertile of dietary Ca:P ratio had a lower odds of developing UC compared to the lowest tertlie (OR: 0.34, 95% CI: 0.13-0.87; p = 0.026).

Conclusion

Our results indicate that a higher ratio of dietary Ca:P ratio might be protective against developing UC. However, further studies are warranted to examine this association in various populations.

Unraveling the link between plasma caffeine concentrations and inflammatory bowel disease risk through Mendelian randomization

BACKGROUND

Caffeine is believed to possess anti-inflammatory properties, yet direct population-based evidence regarding its impact on inflammatory bowel disease (IBD) remains scarce.

OBJECTIVES

In this study, we used 2-sample Mendelian randomization (MR) study to investigate the causal relationship between long-term plasma caffeine concentrations and IBD and its subtypes, ulcerative colitis (UC) and Crohn disease (CD).

METHODS

We used single nucleotide polymorphisms (SNPs) associated with plasma caffeine concentrations at genome-wide significance within a ±100-kb range around the CYP1A2 or AHR genes as instrumental variables. Genome-wide association study (GWAS) data for IBD and its subtypes were obtained from FinnGen and International Inflammatory Bowel Disease Genetics Consortium. We conducted a meta-analysis of MR-related SNPs from both sources and used a multiplicative inverse variance-weighted random effects model to combine the effects of each SNP proxy on exposure to outcomes.

RESULTS

In our study, genetically predicted higher plasma caffeine concentrations were associated with a lower risk of IBD, with an odds ratio (OR) of 0.78 (95% confidence interval [CI]: 0.66, 0.91; PFDR = 0.004). This trend was also observed in UC and CD, with ORs of 0.79 (95% CI: 0.66, 0.94; PFDR = 0.014) and 0.78 (95% CI: 0.62, 0.98; PFDR = 0.032), respectively.

CONCLUSION

Our study indicates a potential causal link between genetically predicted higher plasma caffeine concentrations and a reduced risk of IBD, including its subtypes UC and CD.

Nutrition, Nutritional Status, Micronutrients Deficiency, and Disease Course of Inflammatory Bowel Disease

During the disease course, most Inflammatory Bowel Disease patients present a condition of malnutrition, undernutrition, or even overnutrition. These conditions are mainly due to suboptimal nutritional intake, alterations in nutrient requirements and metabolism, malabsorption, and excessive gastrointestinal losses. A suboptimal nutritional status and low micronutrient serum levels can have a negative impact on both induction and maintenance of remission and on the quality of life of Inflammatory Bowel Disease patients. We performed a systematic review including all the studies evaluating the connection between nutrition, nutrition status (including undernutrition and overnutrition), micronutrient deficiency, and both disease course and therapeutic response in Inflammatory Bowel Disease patients. This systematic review was performed using PubMed/MEDLINE and Scopus. Four main clinical settings concerning the effect of nutrition on disease course in adult Inflammatory Bowel Disease patients were analyzed (induction of remission, maintenance of remission, risk of surgery, post-operative recurrence, and surgery-related complications). Four authors independently reviewed abstracts and manuscripts for eligibility. 6077 articles were found; 762 duplicated studies were removed. Out of 412 full texts analyzed, 227 were included in the review. The evidence summarized in this review showed that many nutritional aspects could be potential targets to induce a better control of symptoms, a deeper remission, and overall improve the quality of life of Inflammatory Bowel Disease patients.

Association between dietary acid load and the odds of ulcerative colitis: a case-control study

Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBDs), which have a pivotal role in weakening the quality of lives of suffering patients. According to some recent studies, significant changes in dietary patterns may have contributed to the increased prevalence of UC. Potential renal acid load (PRAL) is an index used to estimate dietary acid load of the diet. The aim of the current study is to investigate the association between PRAL and odds of UC. The current case-control study included 62 newly diagnosed cases of UC and 124 healthy controls. Dietary habits of participants in the last year were collected with a valid food frequency questionnaire (FFQ). Thereafter, PRAL score was calculated based on a formula containing the dietary intake of protein, phosphorus, potassium, calcium, and magnesium. Participants were categorized according to quartiles of PRAL. Multivariable logistic regression models were used to estimate the odds' ratio (OR) with 95% confidence intervals (CIs) of UC across quartiles of PRAL. The results of the current study indicated that in the crude model, participants in the fourth quartile of PRAL had 2.51 time higher odds of UC compared with those in the first quartile of the PRAL [(OR 2.51; 95% CI 1.03-6.14), (P = 0.043)]. After adjustment for age and biological gender, this positive association remained significant [(OR 2.99; 95% CI 1.16-7.72), (P = 0.023)]. In the final model, after further adjustment for BMI, current smoking, education, Helicobacter pylori infection, and dietary intakes of total energy, omega-3 fatty acids, trans-fatty acids, and total dietary fiber, the odds of UC in the highest quartile of PRAL was significantly higher compared to the lowest quartile [(OR 3.08; 95% CI 1.01-9.39), (P = 0.048)]. So, we observed that higher dietary acid load assessed by PRAL score is associated with greater odds of UC.

Plant-derived exosomal nanoparticles: potential therapeutic for inflammatory bowel disease

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic autoimmune disorder characterized by inflammation. However, currently available disease-modifying anti-IBD drugs exhibit limited efficacy in IBD therapy. Furthermore, existing therapeutic approaches provide only partial relief from IBD symptoms and are associated with certain side effects. In recent years, a novel category of nanoscale membrane vesicles, known as plant-derived exosome-like nanoparticles (PDENs), has been identified in edible plants. These PDENs are abundant in bioactive lipids, proteins, microRNAs, and other pharmacologically active compounds. Notably, PDENs possess immunomodulatory, antitumor, regenerative, and anti-inflammatory properties, making them particularly promising for the treatment of intestinal diseases. Moreover, PDENs can be engineered as targeted delivery systems for the efficient transport of chemical or nucleic acid drugs to the site of intestinal inflammation. In the present study, we provided an overview of PDENs, including their biogenesis, extraction, purification, and construction strategies, and elucidated their physiological functions and therapeutic effects on IBD. Additionally, we summarized the applications and potential of PDENs in IBD treatment while highlighting the future directions and challenges in the field of emerging nanotherapeutics for IBD therapy.

Plant-based diets in gastrointestinal diseases: Which evidence?

Plant-based diets (PBDs), rich in high-quality plant foods, offer multiple benefits for the overall and gastrointestinal health. Recently, it has been demostrated that the positive effects of PBDs on gastrointestinal health can be mediated by the gut microbiota, in particular, by inducing a greater diversity of bacteria. This review summarizes current knowledge on the relationship between nutrition, the gut microbiota, and host metabolic status. We discussed how dietary habits modify the composition and physiological activity of the gut microbiota and how gut dysbiosis affects the most prevalent gastrointestinal diseases, including inflammatory bowel diseases, functional bowel disorders, liver disorders, and gastrointestinal cancer. The beneficial role of PBDs is being increasingly recognized as potentially useful in the management of most diseases of the gastrointestinal tract.

Dietary-Induced Bacterial Metabolites Reduce Inflammation and Inflammation-Associated Cancer via Vitamin D Pathway

Environmental factors, including westernised diets and alterations to the gut microbiota, are considered risk factors for inflammatory bowel diseases (IBD). The mechanisms underpinning diet-microbiota-host interactions are poorly understood in IBD. We present evidence that feeding a lard-based high-fat (HF) diet can protect mice from developing DSS-induced acute and chronic colitis and colitis-associated cancer (CAC) by significantly reducing tumour burden/incidence, immune cell infiltration, cytokine profile, and cell proliferation. We show that HF protection was associated with increased gut microbial diversity and a significant reduction in Proteobacteria and an increase in Firmicutes and Clostridium cluster XIVa abundance. Microbial functionality was modulated in terms of signalling fatty acids and bile acids (BA). Faecal secondary BAs were significantly induced to include moieties that can activate the vitamin D receptor (VDR), a nuclear receptor richly represented in the intestine and colon. Indeed, colonic VDR downstream target genes were upregulated in HF-fed mice and in combinatorial lipid-BAs-treated intestinal HT29 epithelial cells. Collectively, our data indicate that HF diet protects against colitis and CAC risk through gut microbiota and BA metabolites modulating vitamin D targeting pathways. Our data highlights the complex relationship between dietary fat-induced alterations of microbiota-host interactions in IBD/CAC pathophysiology.

Multi-omics reveals diet-induced metabolic disorders and liver inflammation via microbiota-gut-liver axis

The gut microbiota medicated gut-liver axis is vital for liver function and health. We aimed to explore the underlying molecular mechanism of diet-induced metabolic liver disorders via microbiota-gut-liver axis using multi-omics. Metataxonomics, metaproteomics, transcriptomics, and metabolomics were conducted on liver tissue and biofluids (gastrointestinal contents and blood) to elucidate the microbial mechanism related to metabolic disorders and liver injury. The hepatic inflammation occurred based on histomorphology after feeding a long-term grain-based high-energy diet, and the serum biochemical parameters and proinflammatory cytokines were significantly activated. Metaproteomics analysis indicated that the high-energy diet reduced anti-infection, immunity, anti-oxidant functions, and increased cell death and damage of rumen microbiome. Ruminal Ruminococcus_2, Solobacterium, and Syntrophococcu and jejunal Pirellula were potential microbial markers of liver disorders. The high-energy diet promoted hepatic inflammatory response and cytokine/chemokine-mediated signaling pathways located in the core of the functional genomic network. The high-energy diet increased indoxyl sulfate and p-cresol sulfate and decreased triterpenoids in the liver that were the potential biomarkers associated with metabolic liver disorders. Integrated multi-omics analyses showed interactions among the rumen and jejunum microbiota, circulating metabolites, and liver gene expression, suggesting a systemic immune response and liver disorder that signals through the microbiota-gut-liver axis.

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.

Advances in understanding of effects of dietary nutrients in inflammatory bowel disease patients

The occurrence of inflammatory bowel disease (IBD) is influenced by environmental factors. Diet, as an important environmental factor, is closely associated with intestinal ecology and plays a critical role in the pathological process of IBD. This review summarizes the role of major dietary nutrients in the pathogenesis of IBD, with an aim to provide clues for the prevention and treatment of IBD.

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.

Processed Food as a Risk Factor for the Development and Perpetuation of Crohn's Disease-The ENIGMA Study

(1) Background: Developing countries have experienced a rapid recent rise in Inflammatory Bowel Disease (IBD) incidence and emerging evidence suggests processed foods and food additives may predispose one to the development and perpetuation of Crohn’s disease (CD). The aim of this study was to evaluate processed food and food additive intake in CD patients and controls, in Australia (high CD incidence), Hong Kong (intermediate incidence) and mainland China (emerging incidence). (2) Methods: In 274 CD patients (CD), 82 first-degree relatives (FDR), 83 household members (HM) and 92 healthy unrelated controls (HC) from Australia (n = 180), Hong Kong (HK) (n = 160) and mainland China (n = 191) we estimated early life (0–18 years), recent (12 months), and current processed and food additive intake, using validated questionnaires and a 3-day-food diary. (3) Results: Early life processed food intake: Combining all regions, CD were more likely to have consumed soft drinks and fast foods than HM, more likely to have consumed processed fruit and snacks than their FDR, and more likely to have consumed a range of processed foods than HC. HK and China CD patients were more likely to have consumed a range of processed foods than HC. Recent food-additive intake (12-months): Combining all regions, CD patients had significantly higher intakes of aspartame and sucralose, and polysorbate-80, than HC, and more total emulsifiers, artificial sweeteners, and titanium dioxide than FDR and HC. HK and China CD patients had a higher intake of almost all food additives than all controls. Current additive intake (3-days): Australian and HK CD patients had higher total food-additive intake than FDR, and HK CD patients had a higher intake of total food-additives and emulsifiers than HM. (4) Conclusions: CD patients have been exposed to more processed food and food additives than control groups, which may predispose them to CD development and ongoing inflammation.

Meat consumption and all-cause mortality in 5763 patients with inflammatory bowel disease: A retrospective cohort study

BACKGROUND

Whether meat consumption is related to risk of mortality in patients with inflammatory bowel disease (IBD) remains poorly understood.

METHODS

In the UK Biobank, 5763 patients with IBD were recruited from 2007 to 2010 and finished a brief food frequency questionnaire at baseline. We followed them until March 13, 2021 to document all-cause death events. Cox proportional hazard models were used to estimate hazard ratios (HRs) for all-cause mortality associated with consumptions of fish, unprocessed poultry, unprocessed red meat, and processed meat among the patients.

FINDINGS

During 67,095 person-years (mean follow-up 11·7 years, mean age 57·3, 52·5% female), we documented 590 death events. Higher consumption of processed meat was associated with an increased risk of all-cause mortality in patients with IBD (HR comparing >4·0 with 0-0·9 time/week=1·52, 95% confidence interval (CI) 1·05-2·19), but the P-trend for each 25 g increment was 0·075. This association remained significant in patients with Crohn's disease (HR 1·77, 95% CI 1·01-3·10) but not in patients with ulcerative colitis (HR 1·34, 95% CI 0·82-2·20). Consumptions of fish (HR 1·27, 95% CI 0·84-1·91), unprocessed poultry (HR 0·59, 95% CI 0·28-1·21), or unprocessed red meat (HR 0·87, 95% CI 0·60-1·26) were not significantly associated with the mortality of patients with IBD.

INTERPRETATION

More frequent consumption of processed meat was associated with an increased risk of mortality in patients with IBD, while no associations were observed for consumption of other types of meat. Our exploratory and speculative findings should be cautiously interpreted and need further replication in other cohorts.

FUNDING

The National Natural Science Foundation of China (81,970,494); Key Project of Research and Development Plan of Hunan Province (2019SK2041).

Self-reported flares among people living with IBD are associated with stress and worry but not associated with recent diet changes: The Manitoba Living with IBD Study

BACKGROUND

In this matched case-control longitudinal study among people living with inflammatory bowel disease (IBD), we investigated beliefs about what triggers a flare.

METHODS

Adults with confirmed IBD and active disease within 2 years were enrolled in the Manitoba Living with IBD Study and followed biweekly with online surveys for 1 year. The 7-point IBD Symptom Change Indicator was used for participant identification of a flare. Flare cases were matched to non-flare controls by sex and disease type. Members of each matched pair completed supplemental information on diet changes and psychological functioning in the previous two weeks, and provided stool samples to assess fecal calprotectin (FCAL).

RESULTS

Of 128 enrolled participants, 95 matched flare/non-flare pairs were created. Those reporting a flare were more likely to have elevated FCAL (51% vs 34% among non-flares, p=0.043). Although 61% of study participants believed at baseline that a food may trigger flares, and 25% of those in a flare believed that a food may have triggered their current flare, there was no difference in consumption of assessed foods between flares and non-flares in the previous two weeks. Flares were more likely to be having difficulties in emotional state than controls (40% vs 18%, p=0.001) and more likely to be stressed or worried (64% vs 33%, p=0.001).

CONCLUSION

While a majority of individuals with IBD believe that specific foods trigger their disease flares, this was not supported by the current findings. Recent psychological functioning was associated with self-reported IBD flare. This article is protected by copyright. All rights reserved.

Dietary Habits of a Group of Children with Crohn’s Disease Compared to Healthy Subjects: Assessment of Risk of Nutritional Deficiencies through a Bromatological Analysis

Diet is a matter of interest in the pathogenesis and management of Crohn’s Disease (CD). Little is known about CD children’s dietary habits. Our aim was assessing the quality and the amount of nutrient intake in a group of CD pediatric patients. Data were compared with those of healthy subjects (HS). In total, 20 patients (13 males) and 48 HS (24 males) aged 4–18 years were provided with a food diary to fill out for one week. Winfood software performed the bromatological analysis, providing data about intakes of proteins and amino acids, fatty acids, carbohydrates, cholesterol, fibers, minerals, vitamins, and polyphenols. Estimates of the antioxidant activity of foods and of the dietetic protein load were also calculated. The diet of CD patients was poorer in fibers, polyphenols, vitamin A, beta-carotene, and fatty acids, and richer in animal proteins, vitamin B12, and niacin. PRAL was higher in CD patients’ diets, while ORAC was higher in HS. No significant differences were observed in carbohydrate and other macro- and micronutrient consumptions. CD dietary habits seem to reflect the so-called Western diet, possibly involved in CD pathogenesis. Furthermore, analysis of dietary habits allows for prevention of nutritional deficiencies and timely correction through education and supplementation.

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.

Diet and microbiome in the beginning of the sequence of gut inflammation

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract due, at least partially, to an aberrant and excessive mucosal immune response to gut bacteria in genetically-predisposed individuals under certain environmental factors. The incidence of IBD is rising in western and newly industrialized countries, paralleling the increase of westernized dietary patterns, through new antigens, epithelial function and permeability, epigenetic mechanisms (e.g., DNA methylation), and alteration of the gut microbiome. Alteration in the composition and functionality of the gut microbiome (including bacteria, viruses and fungi) seems to be a nuclear pathogenic factor. The microbiome itself is dynamic, and the changes in food quality, dietary habits, living conditions and hygiene of these western societies, could interact in a complex manner as modulators of dysbiosis, thereby influencing the activation of immune cells' promoting inflammation. The microbiome produces diverse small molecules via several metabolic ways, with the fiber-derived short-chain fatty acids (i.e., butyrate) as main elements and having anti-inflammatory effects. These metabolites and some micronutrients of the diet (i.e., vitamins, folic acid, beta carotene and trace elements) are regulators of innate and adaptive intestinal immune homeostasis. An excessive and unhealthy consumption of sugar, animal fat and a low-vegetable and -fiber diet are risk factors for IBD appearance. Furthermore, metabolism of nutrients in intestinal epithelium and in gut microbiota is altered by inflammation, changing the demand for nutrients needed for homeostasis. This role of food and a reduced gut microbial diversity in causing IBD might also have a prophylactic or therapeutic role for IBD. The relationship between dietary intake, symptoms, and bowel inflammation could lead to dietary and lifestyle recommendations, including diets with abundant fruits, vegetables, olive oil and oily fish, which have anti-inflammatory effects and could prevent dysbiosis and IBD. Dietary modulation and appropriate exclusion diets might be a new complementary management for treatment at disease flares and in refractory patients, even reducing complications, hospitalizations and surgery, through modifying the luminal intestinal environment.

Adherence to mediterranean diet in patients with inflammatory bowel disease

BACKGROUND & AIMS

Mediterranean diet may be beneficial for inflammatory bowel disease (IBD). The aim of this study was to evaluate the level of adherence to MD in Italian patients with IBD.

METHODS

Eighty consecutive outpatients with IBD, 62 with Crohn's Disease (CD) and 18 with Ulcerative Colitis (UC) were included in the study. Demographic and clinical data, previous and current medical history, nutritional status and Quality of Life (QoL) assessed with the Short Inflammatory Bowel Disease Questionnaire (SIBDQ) were assessed. Adherence to MD was studied with the Medi-Lite questionnaire.

RESULTS

IBD patients reported a mean Medi-Lite score of 10.4 with no significant differences between CD and UC patients (p = 0.543). Among CD patients, adherence to MD was higher in patients with inactive disease (p < 0.001) than in patients during the active phase, while no significant difference was found regarding disease activity in UC patients. A significant negative correlation of the Medi-Lite score with SIBDQ score (r = -0.2; p = 0.040) was found. MD adherence was lower in CD patients who had undergone ≥2 surgeries, whereas for patients with UC we found no significant differences in MD adherence in relation to pervious surgery.

CONCLUSIONS

Adherence to MD in IBD is influenced by disease activity, QoL and patients' surgical history. A greater adherence to MD achieved with nutritional education may help improve quality of life and modulate disease activity.

GPR35 in Intestinal Diseases: From Risk Gene to Function

Diet and gut microbial metabolites mediate host immune responses and are central to the maintenance of intestinal health. The metabolite-sensing G-protein coupled receptors (GPCRs) bind metabolites and trigger signals that are important for the host cell function, survival, proliferation and expansion. On the contrary, inadequate signaling of these metabolite-sensing GPCRs most likely participate to the development of diseases including inflammatory bowel diseases (IBD). In the intestine, metabolite-sensing GPCRs are highly expressed by epithelial cells and by specific subsets of immune cells. Such receptors provide an important link between immune system, gut microbiota and metabolic system. Member of these receptors, GPR35, a class A rhodopsin-like GPCR, has been shown to be activated by the metabolites tryptophan-derived kynurenic acid (KYNA), the chemokine CXCL17 and phospholipid derivate lysophosphatidic acid (LPA) species. There have been studies on GPR35 in the context of intestinal diseases since its identification as a risk gene for IBD. In this review, we discuss the pharmacology of GPR35 including its proposed endogenous and synthetic ligands as well as its antagonists. We elaborate on the risk variants of GPR35 implicated in gut-related diseases and the mechanisms by which GPR35 contribute to intestinal homeostasis.

Dietary Regulation of the Crosstalk between Gut Microbiome and Immune Response in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), a chronic, recurring inflammatory response, is a growing global public health issue. It results from the aberrant crosstalk among environmental factors, gut microbiota, the immune system, and host genetics, with microbiota serving as the core of communication for differently-sourced signals. In the susceptible host, dysbiosis, characterized by the bloom of facultative anaerobic bacteria and the decline of community diversity and balance, can trigger an aberrant immune response that leads to reduced tolerance against commensal microbiota. In IBD, such dysbiosis has been profoundly proven in animal models, as well as clinic data analysis; however, it has not yet been conclusively ascertained whether dysbiosis actually promotes the disease or is simply a consequence of the inflammatory disorder. Better insight into the complex network of interactions between food, the intestinal microbiome, and host immune response will, therefore, contribute significantly to the diagnosis, treatment, and management of IBD. In this article, we review the ways in which the mutualistic circle of dietary nutrients, gut microbiota, and the immune system becomes anomalous during the IBD process, and discuss the roles of bacterial factors in shaping the intestinal inflammatory barrier and adjusting immune capacity.

Systematic review and meta-analysis: Association of a pre-illness Western dietary pattern with the risk of developing inflammatory bowel disease

OBJECTIVE

Previous studies have presented conflicting results on Western diets and the risk of inflammatory bowel disease (IBD). This study aimed to evaluate the role of a pre-illness Western dietary pattern in the development of IBD.

METHODS

The Western dietary pattern was defined as that met at least two of the following, either a high intake of refined grains, red and processed meat, animal protein, animal fats or high-fat dairy products, or with a low consumption of fruit and vegetables. Four medical databases (PubMed, EMBASE, the Cochrane Library and the China National Knowledge Infrastructure) were searched to identify all relevant references. Risk estimate and corresponding 95% confidence interval (CI) were pooled using a random-effects model.

RESULTS

Nine studies (seven case-control studies and two prospective cohorts) were included, with a total of 1491 IBD cases and 53 089 controls. A Western dietary pattern was associated with a risk of all IBD (relative risk [RR] 1.92, 95% CI 1.37-2.68) and separately with Crohn's disease (CD) (RR 1.72, 95% CI 1.01-2.93) and ulcerative colitis (UC) (RR 2.15, 95% CI 1.38-3.34). Subgroup analysis by region showed that a Western dietary pattern was associated with the risk of CD and UC for studies performed in Europe (RR 2.25, 95% CI 1.44-3.50 for CD; RR 2.65, 95% CI 1.61-4.36 for UC). The pooled RR was 2.26 (95% CI 1.42-3.59) in the pediatric CD subgroup.

CONCLUSION

This meta-analysis indicates that a pre-illness Western dietary pattern may increase the risk of developing CD and UC.

Examination of food consumption in United States adults and the prevalence of inflammatory bowel disease using National Health Interview Survey 2015

Various diets and food components have been implicated as one of the environmental factors associated with inflammatory bowel disease (IBD). Patients are often recommended nutritional guidelines to manage disease symptoms. However, the current food consumption pattern of US adults with IBD that are nationally representative is unclear. A secondary analysis of National Health Interview Survey 2015 was performed to characterize the estimated US adults with IBD and their food intake and consumption frequency using bivariate and multivariate logistic regression. Fries were consumed by a greater number of people with IBD. IBD population drank less 100% fruit juice and ate more cheese and cookies than non-IBD population. Intake of fries (OR 1.60, 95% CI 1.14-2.25) and sports and energy drinks (OR 1.46, 95% CI 1.07-1.97) and more frequent drinking of regular soda were significantly associated with the likelihood of having been told one have IBD, while popcorn (OR 0.73, 95% CI 0.548-0.971) and milk (OR 0.70, 95% CI 0.497-0.998) were associated with smaller odds, adjusting for covariates. Foods typically labeled as junk food were positively associated with IBD. Nonetheless, of the assessed 26 foods, we found eating patterns between IBD and non-IBD population to be mostly analogous. It is unclear whether the results reflect potential change in food intake in IBD population long before the survey interview. Understanding the role of food intake in IBD risk/prevalence would benefit from identifying other environmental factors (i.e. food desert), food processing (i.e. frying), and potential bioactive food components that can induce intestinal inflammation that can increase the individual's susceptibility to IBD.

Marked regional variations in the prevalence of inflammatory bowel disease in a limited geographical region are not associated with compounds in the drinking water

Objective: The incidence of autoimmune diseases, especially inflammatory bowel disease (IBD), has increased substantially. Globally, there are vast differences varying from 0.2/10⁵ in some Asian countries to over 80/10⁵ in the Faroe Islands. Environmental factors have been suggested as triggers. The aim was to investigate the incidence and prevalence of IBD in the 33 municipalities in the county Scania in Southern Sweden, an area comprising 100 × 100 km with 1,274,069 inhabitants. Furthermore, we wanted to explore whether compounds in the drinking water could contribute to IBD; one report from Norway has suggested that iron in drinking water could contribute to UC.Methods: Patients with CD and UC were identified through the ICD-10 diagnosis database during the period 2000-2013. Water analyses for pH, alkaline, nitrate, sulphate, iron, magnesium and calcium were based on established methods and compared with the prevalence of IBD using Student's t-test.Results: A total number of 8925 patients were identified. The incidence for CD and UC were high (mean 16.4/10⁵, range 13.6-17.9 and 25.3/10⁵, range 21.3-28.0, respectively). The prevalence varied substantially (p < .0001 for both; CD mean 0.30%, range 0.15-0.42 and UC mean 0.42%, range 0.32-0.56). No correlation between IBD and the chemical compounds in the drinking water could be shown.Conclusions: The incidence rates of both CD and UC were high. The prevalence varied from 200% to 300% between the municipalities, despite the limited geographical area indicating that local conditions are of importance. However, chemical compounds in the water were not associated with this variation.

Beneficial effects of nutritional supplements on intestinal epithelial barrier functions in experimental colitis models in vivo

Acute and chronic colitis affect a huge proportion of the population world-wide. The etiology of colitis cases can be manifold, and diet can significantly affect onset and outcome of colitis. While many forms of acute colitis are easily treatable, chronic forms of colitis such as ulcerative colitis and Crohn’s disease (summarized as inflammatory bowel diseases) are multifactorial with poorly understood pathogenesis. Inflammatory bowel diseases are characterized by exacerbated immune responses causing epithelial dysfunction and bacterial translocation. There is no cure and therapies aim at reducing inflammation and restoring intestinal barrier function. Unfortunately, most drugs can have severe side effects. Changes in diet and inclusion of nutritional supplements have been extensively studied in cell culture and animal models, and some supplements have shown promising results in clinical studies. Most of these nutritional supplements including vitamins, fatty acids and phytochemicals reduce oxidative stress and inflammation and have shown beneficial effects during experimental colitis in rodents induced by dextran sulphate sodium or 2,4,6-trinitrobenzene sulfonic acid, which remain the gold standard in pre-clinical colitis research. Here, we summarize the mechanisms through which such nutritional supplements contribute to epithelial barrier stabilization.

Dietary Beliefs and Behaviors Among Parents of Children with Inflammatory Bowel Disease

Diet is regarded as one of the important environmental factors triggering inflammatory bowel disease (IBD). Many IBD patients avoid numerous types of foods in fear of disease exacerbation. The aim of the study was to investigate dietary beliefs and food avoidance among pediatric patients with IBD. This questionnaire-based study was conducted in three University-affiliated children's hospitals in Poland. Data were collected from parents of children who were diagnosed with IBD. A total of 155 parents of IBD patients participated in the survey: 104 (67.1%) had a child with Crohn's disease and 51 (32.9%) with ulcerative colitis. Parents of older children and those with longer disease duration predicted diet being considered one of the causative agents of IBD, and differences were statistically significant (P = .01 and P = .04, respectively). Also, patients with a shorter history of disease rarely shared food with other family members (P = .02). In total, 61.5% of patients avoided some kind of food in fear of disease flares. In the parent's opinion, the food the children liked but avoided included fried dishes, sweets (e.g., chocolate, cookies, cakes, candies, jellies), and fast food. Due to their dietary beliefs, parents of children with IBD commonly introduced dietary restrictions for their offspring. Frequent and unjustified food avoidance may influence not only nutritional status but also general well-being of pediatric patients. Our results underscore the urgent need for IBD patients and parents of ill children to receive reliable dietary advice based on strong scientific evidence.

Beverage intake and risk of Crohn disease: A meta-analysis of 16 epidemiological studies

Epidemiological studies were controversial in the association between beverage intake and risk of Crohn disease (CD). This study aimed to investigate the role of beverage intake in the development of CD. A systematic search was conducted in public databases to identify all relevant studies, and study-specific relative risks (RRs) and 95% confidence intervals (CIs) were pooled using a random-effects model. Sixteen studies were identified with a total of 130,431 participants and 1933 CD cases. No significant association was detected between alcohol intake and CD risk (RR for the highest vs the lowest consumption level: 0.85, 95% CI 0.68-1.08), and coffee intake and the risk (RR 0.82, 95% CI 0.46-1.46). High intake of soft drinks was associated with CD risk (RR 1.42, 95% CI 1.01-1.98), and tea intake was inversely associated with CD risk (RR 0.70, 95% CI 0.53-0.93). In conclusion, high intake of soft drinks might increase the risk of CD, whereas tea intake might decrease the risk.

Diet Rich in Animal Protein Promotes Pro-inflammatory Macrophage Response and Exacerbates Colitis in Mice

Diet is a major factor determining gut microbiota composition and perturbances in this complex ecosystem are associated with the inflammatory bowel disease (IBD). Here, we used gnotobiotic approach to analyze, how interaction between diet rich in proteins and gut microbiota influences the sensitivity to intestinal inflammation in murine model of ulcerative colitis. We found that diet rich in animal protein (aHPD) exacerbates acute dextran sulfate sodium (DSS)-induced colitis while diet rich in plant protein (pHPD) does not. The deleterious effect of aHPD was also apparent in chronic DSS colitis and was associated with distinct changes in gut bacteria and fungi. Therefore, we induced acute DSS-colitis in germ-free mice and transferred gut microbiota from aCD or aHPD fed mice to find that this effect requires presence of microbes and aHPD at the same time. The aHPD did not change the number of regulatory T cells or Th17 cells and still worsened the colitis in immuno-deficient RAG2 knock-out mice suggesting that this effect was not dependent on adaptive immunity. The pro-inflammatory effect of aHPD was, however, abrogated when splenic macrophages were depleted with clodronate liposomes. This treatment prevented aHPD induced increase in colonic Ly-6C^high pro-inflammatory monocytes, but the ratio of resident Ly-6C^−/low macrophages was not changed. These data show that the interactions between dietary protein of animal origin and gut microbiota increase sensitivity to intestinal inflammation by promoting pro-inflammatory response of monocytes.

Dietary Protein Intake Level Modulates Mucosal Healing and Mucosa-Adherent Microbiota in Mouse Model of Colitis

Mucosal healing after an inflammatory flare is associated with lasting clinical remission. The aim of the present work was to evaluate the impact of the amount of dietary protein on epithelial repair after an acute inflammatory episode. C57BL/6 DSS-treated mice received isocaloric diets with different levels of dietary protein: 14% (P14), 30% (P30) and 53% (P53) for 3 (day 10), 6 (day 13) and 21 (day 28) days after the time of colitis maximal intensity. While the P53 diet worsened the DSS- induced inflammation both in intensity and duration, the P30 diet, when compared to the P14 diet, showed a beneficial effect during the epithelial repair process by accelerating inflammation resolution, reducing colonic permeability and increasing epithelial repair together with epithelial hyperproliferation. Dietary protein intake also impacted mucosa-adherent microbiota composition after inflammation since P30 fed mice showed increased colonization of butyrate-producing genera throughout the resolution phase. This study revealed that in our colitis model, the amount of protein in the diet modulated mucosal healing, with beneficial effects of a moderately high-protein diet, while very high-protein diet displayed deleterious effects on this process.

The Role of Dietary Nutrients in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disease of the gastrointestinal tract. Although the precise etiology of IBD remains incompletely understood, accumulating evidence suggests that various environmental factors, including dietary nutrients, contribute to its pathogenesis. Dietary nutrients are known to have an impact on host physiology and diseases. The interactions between dietary nutrients and intestinal immunity are complex. Dietary nutrients directly regulate the immuno-modulatory function of gut-resident immune cells. Likewise, dietary nutrients shape the composition of the gut microbiota. Therefore, a well-balanced diet is crucial for good health. In contrast, the relationships among dietary nutrients, host immunity and/or the gut microbiota may be perturbed in the context of IBD. Genetic predispositions and gut dysbiosis may affect the utilization of dietary nutrients. Moreover, the metabolism of nutrients in host cells and the gut microbiota may be altered by intestinal inflammation, thereby increasing or decreasing the demand for certain nutrients necessary for the maintenance of immune and microbial homeostasis. Herein, we review the current knowledge of the role dietary nutrients play in the development and the treatment of IBD, focusing on the interplay among dietary nutrients, the gut microbiota and host immune cells. We also discuss alterations in the nutritional metabolism of the gut microbiota and host cells in IBD that can influence the outcome of nutritional intervention. A better understanding of the diet-host-microbiota interactions may lead to new therapeutic approaches for the treatment of IBD.

The role of diet in the prevention and treatment of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) – Crohn’s disease (CD) and ulcerative colitis (UC) – are chronic conditions characterised by relapsing inflammation of the gastrointestinal tract. They represent an increasing public health concern and an aetiological enigma due to unknown causal factors. The current knowledge on the pathogenesis of IBD is that genetically susceptible individuals develop intolerance to a dysregulated gut microflora (dysbiosis) and chronic inflammation develops as a result of environmental triggers. Among the environmental factors associated with IBD, diet plays an important role in modulating the gut microbiome, and, consequently, it could have a therapeutic impact on the disease course. An overabundance of calories and some macronutrients typical of the Western dietetic pattern increase gut inflammation, whereas several micronutrients characteristic of the Mediterranean Diet have the potential to modulate gut inflammation, according to recent evidence. Immunonutrition has emerged as a new concept putting forward the role of vitamins such as vitamins A, C, E, and D, folic acid, beta carotene and trace elements such as zinc, selenium, manganese and iron. However, when assessed in clinical trials, specific micronutrients showed a limited benefit. Further research is required to evaluate the role of individual food compounds and complex nutritional interventions with the potential to decrease inflammation as a means of prevention and management of IBD. The current dietary recommendations for disease prevention and management are scarce and non evidence-based. This review summarizes the current knowledge on the complex interaction between diet, microbiome and immune-modulation in IBD, with particular focus to the role of the Mediterranean Diet as a tool for prevention and treatment of the disease. (www.actabiomedica.it)

High-protein diets for weight management: Interactions with the intestinal microbiota and consequences for gut health. A position paper by the my new gut study group

BACKGROUND & AIMS

This review examines to what extent high-protein diets (HPD), which may favor body weight loss and improve metabolic outcomes in overweight and obese individuals, may also impact the gut environment, shaping the microbiota and the host-microbe (co)metabolic pathways and products, possibly affecting large intestine mucosa homeostasis.

METHODS

PubMed-referenced publications were analyzed with an emphasis on dietary intervention studies involving human volunteers in order to clarify the beneficial vs. deleterious effects of HPD in terms of both metabolic and gut-related health parameters; taking into account the interactions with the gut microbiota.

RESULTS

HPD generally decrease body weight and improve blood metabolic parameters, but also modify the fecal and urinary contents in various bacterial metabolites and co-metabolites. The effects of HPD on the intestinal microbiota composition appear rather heterogeneous depending on the type of dietary intervention. Recently, HPD consumption was shown to modify the expression of genes playing key roles in homeostatic processes in the rectal mucosa, without evidence of intestinal inflammation. Importantly, the effects of HPD on the gut were dependent on the protein source (i.e. from plant or animal sources), a result which should be considered for further investigations.

CONCLUSION

Although HPD appear to be efficient for weight loss, the effects of HPD on microbiota-derived metabolites and gene expression in the gut raise new questions on the impact of HPD on the large intestine mucosa homeostasis leading the authors to recommend some caution regarding the utilization of HPD, notably in a recurrent and/or long-term ways.

Diet and Anthropometrics of Children With Inflammatory Bowel Disease: A Comparison With the General Population

BACKGROUND

There is a lack of knowledge regarding the diet of children with inflammatory bowel disease (IBD). Therefore, we investigated dietary intake in pediatric IBD compared to the general population and assessed anthropometrics and food avoidance.

METHODS

In this cross-sectional cohort study, patients younger than 18 years with IBD were included (2014-2017). Dietary intake (total energy, macro nutrients, food types) was assessed using a Food Frequency Questionnaire (FFQ) and compared with a matched reference population (n = 306).

RESULTS

There were 102 patients included (55% male, median age 15.0 years). Median height Z-score was -0.39 (interquartile range [IQR]: -1.17 to 0.26). Growth failure (height Z-scores<-1.64) was present in 11% of patients. Median BMI Z-score was 0.36 (IQR: -0.70 to 0.96). Acute malnutrition (weight-for-height Z-score<-2) was present in 3% of patients. Energy intake was lower in pediatric IBD compared to the reference population (mean kilojoule/day: 8286 vs 9794, P < 0.001). Protein intake did not differ, while fat intake was higher in pediatric IBD (mean gram/day: 101 vs 91, P < 0.001), with higher intake of vegetable oils/fats. Carbohydrate intake was lower in pediatric IBD (mean gram/day: 267 vs 305, P < 0.001), with lower intake of food types high in sugar. Food avoidance was reported in 53% of patients, with frequent avoidance of spicy (46%), high-fat food (30%), and dairy (30%).

CONCLUSIONS

The diet of children with IBD differs from the general pediatric population, with lower energy intake and high rates of food avoidance. Evaluation of the dietary intake alongside anthropometrics may be important to prevent nutrition deficiencies and promote health.

Dietary intake of patients with inflammatory bowel disease: A comparison with individuals from a general population and associations with relapse

BACKGROUND AND AIMS

Individuals with inflammatory bowel disease (IBD) often hold strong beliefs on how diet impacts their disease. This study aimed to compare dietary intakes between IBD patients and individuals from the general population and to assess associations of dietary factors with relapse in patients with IBD.

METHODS

Patients with longstanding Crohn's disease and ulcerative colitis (n = 165) filled out food frequency questionnaires, as did individuals participating in a Dutch population-based study (controls) (n = 1469). Multivariable regression analyses were used to assess differences in habitual dietary intake between IBD patients and controls, and to estimate associations of dietary factors in patients in remission with the development of disease relapse at follow-up.

RESULTS

IBD patients had higher intakes of animal protein (3.50 g/d, 95% confidence interval (CI) 1.67-5.34) and carbohydrate (10.1 g/d, 95% CI 5.23-14.9) than controls and lower intakes of (unsaturated) fat (-3.53 g/d, 95% CI -5.57- -1.50), dietary fiber (-2.19 g/d, 95% CI -3.05- -1.32) and alcohol (-0.84 g/d, 95% CI -1.46- -0.22). This was explained by a higher consumption of carbonated beverages, meat and poultry and lower consumption of fruit, vegetables and dairy products (except cheese) by IBD patients compared with controls. Several dietary factors, particularly (saturated) fat and fiber, appeared to be associated with risk of relapse.

CONCLUSIONS

IBD patients had higher dietary intakes of (animal) protein and carbohydrate and lower intakes of (unsaturated) fat, dietary fiber and alcohol compared with a general Dutch population. The results further underscore that dietary factors may have a role in disease course.

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.

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

BACKGROUND AND AIMS

Population-based prospective cohort studies investigating fibre intake and development of inflammatory bowel disease are lacking. Our aim was to investigate the association between fibre intake and the development of Crohn's disease [CD] and ulcerative colitis [UC] in a large European population.

METHODS

In total, 401326 participants, aged 20-80 years, were recruited in eight countries in Europe between 1991 and 1998. At baseline, fibre intake [total fibres, fibres from fruit, vegetables and cereals] was recorded using food frequency questionnaires. The cohort was monitored for the development of inflammatory bowel disease. Each case was matched with four controls and odds ratios [ORs] for the exposures were calculated using conditional logistic regression. Sensitivity analyses according to smoking status were computed.

RESULTS

In total, 104 and 221 participants developed incident CD and UC, respectively. For both CD and UC, there were no statistically significant associations with either quartiles, or trends across quartiles, for total fibre or any of the individual sources. The associations were not affected by adjusting for smoking and energy intake. Stratification according to smoking status showed null findings apart from an inverse association with cereal fibre and CD in non-smokers [Quartile 4 vs 1 OR = 0.12, 95% confidence interval = 0.02-0.75, p = 0.023, OR trend across quartiles = 0.50, 95% confidence interval = 0.29-0.86, p = 0.017].

CONCLUSION

The results do not support the hypothesis that dietary fibre is involved in the aetiology of UC, although future work should investigate whether there may be a protective effect of specific types of fibre according to smoking status in CD.

Dietary Patterns in women with Inflammatory Bowel Disease and Risk of Adverse Pregnancy Outcomes: Results from The Norwegian Mother and Child Cohort Study (MoBa)

BACKGROUND

The aim of the study was to examine dietary patterns and risk of adverse pregnancy outcomes among mothers with inflammatory bowel disease (IBD) in the Norwegian Mother and Child Cohort Study (MoBa).

METHOD

MoBa enrolled participants from all over Norway between 1999 and 2008, and the study comprised 83,988 mothers, of whom there were 183 mothers with Crohn's disease (CD) and 240 with ulcerative colitis (UC). An additional questionnaire was submitted to mothers with IBD in 2013. We extracted three exploratory dietary patterns: a "Prudent," a "Western," and a "Traditional" pattern. We explored the relationship between dietary patterns and IBD and dietary patterns and adverse pregnancy outcomes: small for gestational age (SGA) and preterm delivery (PTD).

RESULTS

IBD mothers had a significantly lower adherence to the Traditional dietary pattern [mean score -0.10 (95% CI: - 0.2 - - 0.01)] than non-IBD mothers. In IBD mothers, middle and high adherence to the Traditional dietary pattern was associated with lower risk of SGA [OR tertile 2 vs. tertile 1: 0.44 (95% CI: 0.20 - 0.97) and OR tertile 3 vs. tertile 1: 0.23 (95% CI: 0.08-0.61)] than in IBD and non-IBD mothers with low adherence. In the IBD-subset analyses, similar results were demonstrated for UC mothers [OR tertile 2 vs. tertile 1: 0.21 (95% CI: 0.05 - 0.80) and OR tertile 3 vs. tertile 1: 0.16 (95% CI: 0.04 - 0.60)].

CONCLUSION

In IBD mothers, higher adherence to a Traditional dietary pattern, characterized by high consumption of lean fish, fish products, potatoes, rice porridge, cooked vegetables, and gravy, was associated with lower risk of SGA.

Research Gaps in Diet and Nutrition in Inflammatory Bowel Disease. A Topical Review by D-ECCO Working Group [Dietitians of ECCO]

Although the current doctrine of IBD pathogenesis proposes an interaction between environmental factors and gut microbiota in genetically susceptible individuals, dietary exposures have attracted recent interest and are, at least in part, likely to explain the rapid rise in disease incidence and prevalence. The D-ECCO working group along with other ECCO experts with expertise in nutrition, microbiology, physiology, and medicine reviewed the evidence investigating the role of diet and nutritional therapy in the onset, perpetuation, and management of IBD. A narrative topical review is presented where evidence pertinent to the topic is summarised collectively under three main thematic domains: i] the role of diet as an environmental factor in IBD aetiology; ii] the role of diet as induction and maintenance therapy in IBD; and iii] assessment of nutritional status and supportive nutritional therapy in IBD. A summary of research gaps for each of these thematic domains is proposed, which is anticipated to be agenda-setting for future research in the area of diet and nutrition in IBD.

Diet as a Therapeutic Option for Adult Inflammatory Bowel Disease

There are many mechanisms to explain how food may drive and ameliorate inflammation. Although there are no consistent macronutrient associations inflammatory bowel disease (IBD) development, many exclusion diets have been described: IgG-4 guided exclusion diet; semivegetarian diet; low-fat, fiber-limited exclusion diet; Paleolithic diet; Maker's diet; vegan diet; Life without Bread diet; exclusive enteral nutrition (EEN), the Specific Carbohydrate Diet (SCD) and the low FODMAP diet. The literature on diet and IBD is reviewed with a particular focus on EEN, SCD, and low FODMAP diets. Lessons learned from the existing observations and strengths and shortcomings of existing data are presented.

Beverage consumption and risk of ulcerative colitis: Systematic review and meta-analysis of epidemiological studies

Epidemiological studies have provided controversial evidence between beverage consumption and the risk of ulcerative colitis (UC). This study aimed to determine the role of beverage consumption in the development of UC. A systematic search was conducted in public databases to identify all relevant studies, and study-specific relative risks (RRs) and 95% confidence intervals (CIs) were pooled using a random-effects model. Sixteen studies were identified with a total of 3689 cases and 335,339 controls. Alcohol consumption showed no significant association with UC risk (RR for the highest vs the lowest consumption level: 0.95, 95% CI: 0.65-1.39). Coffee consumption tended to be inversely associated with UC risk (RR: 0.58, 95% CI: 0.33-1.05), but it was not significant and confounded by smoking adjustment. Soft drinks consumption was associated with UC risk (RR: 1.69, 95% CI: 1.24-2.30), and tea consumption was inversely associated with UC risk (RR: 0.69, 95% CI: 0.58-0.83). In conclusion, high consumption of soft drinks might increase the risk of UC, while tea consumption might decrease the risk.

Quantity and source of dietary protein influence metabolite production by gut microbiota and rectal mucosa gene expression: a randomized, parallel, double-blind trial in overweight humans

Background: Although high-protein diets (HPDs) are frequently consumed for body-weight control, little is known about the consequences for gut microbiota composition and metabolic activity and for large intestine mucosal homeostasis. Moreover, the effects of HPDs according to the source of protein need to be considered in this context.Objective: The objective of this study was to evaluate the effects of the quantity and source of dietary protein on microbiota composition, bacterial metabolite production, and consequences for the large intestinal mucosa in humans.Design: A randomized, double-blind, parallel-design trial was conducted in 38 overweight individuals who received a 3-wk isocaloric supplementation with casein, soy protein, or maltodextrin as a control. Fecal and rectal biopsy-associated microbiota composition was analyzed by 16S ribosomal DNA sequencing. Fecal, urinary, and plasma metabolomes were assessed by ¹H-nuclear magnetic resonance. Mucosal transcriptome in rectal biopsies was determined with the use of microarrays.Results: HPDs did not alter the microbiota composition, but induced a shift in bacterial metabolism toward amino acid degradation with different metabolite profiles according to the protein source. Correlation analysis identified new potential bacterial taxa involved in amino acid degradation. Fecal water cytotoxicity was not modified by HPDs, but was associated with a specific microbiota and bacterial metabolite profile. Casein and soy protein HPDs did not induce inflammation, but differentially modified the expression of genes playing key roles in homeostatic processes in rectal mucosa, such as cell cycle or cell death.Conclusions: This human intervention study shows that the quantity and source of dietary proteins act as regulators of gut microbiota metabolite production and host gene expression in the rectal mucosa, raising new questions on the impact of HPDs on the large intestine mucosa homeostasis. This trial was registered at clinicaltrials.gov as NCT02351297.

A 20-Year Temporal Change Analysis in Incidence, Presenting Phenotype and Mortality, in the Dutch IBDSL Cohort-Can Diagnostic Factors Explain the Increase in IBD Incidence?

BACKGROUND

The aim was to study temporal changes in incidence, disease phenotype at diagnosis, and mortality of adult inflammatory bowel disease [IBD] patients in South Limburg, The Netherlands, diagnosed between 1991 and 2010. In addition, the 2010 IBD prevalence was estimated.

METHODS

A multi-faceted approach including hospital administrations, the national pathology registry [PALGA], and general practitioners led to the identification of 1162 patients with Crohn's disease [CD], 1663 with ulcerative colitis [UC], and 84 with unclassified IBD [IBD-U]. Temporal changes in incidence, disease phenotype, and mortality were studied using linear, multinomial regression analyses, and standardised mortality rates [SMR], respectively.

RESULTS

The annual incidences increased from 17.90/100000 in 1991 to 40.36/100000 in 2010 for IBD, from 5.84/100000 to 17.49/100000 for CD, and from 11.67/100000 to 21.47/100000 for UC [p < 0.01 for all]. A shift towards milder disease at diagnosis was observed over time [eg decrease of complicated disease in CD, increase of proctitis in UC]. IBD mortality was similar to that in the general population (SMR 0.92; 95% confidence interval [CI] 0.81-1.05), and did not change over time. The estimated IBD prevalence was 830/100000.

CONCLUSIONS

The IBD incidence in South Limburg increased significantly between 1991 and 2010. The shift towards milder disease at diagnosis in parallel with the improved diagnostics and ability to detect low-grade inflammation was suggestive of an important role of diagnostic factors in this increase. Environmental factors probably played a role as well. The mortality was low and, together with the increasing incidence, led to the high prevalence of IBD in South Limburg.

Diet, Gut Microbiome and Epigenetics: Emerging Links with Inflammatory Bowel Diseases and Prospects for Management and Prevention

Inflammatory bowel diseases (IBD) represent a growing public health concern due to increasing incidence worldwide. The current notion on the pathogenesis of IBD is that genetically susceptible individuals develop intolerance to dysregulated gut microflora (dysbiosis) and chronic inflammation develops as a result of environmental triggers. Among the environmental factors associated with IBD, diet plays an important role in modulating the gut microbiome, influencing epigenetic changes, and, therefore, could be applied as a therapeutic tool to improve the disease course. Nevertheless, the current dietary recommendations for disease prevention and management are scarce and have weak evidence. This review summarises the current knowledge on the complex interactions between diet, microbiome and epigenetics in IBD. Whereas an overabundance of calories and some macronutrients increase gut inflammation, several micronutrients have the potential to modulate it. Immunonutrition has emerged as a new concept putting forward the importance of vitamins such as vitamins A, C, E, and D, folic acid, beta carotene and trace elements such as zinc, selenium, manganese and iron. However, when assessed in clinical trials, specific micronutrients exerted a limited benefit. Beyond nutrients, an anti-inflammatory dietary pattern as a complex intervention approach has become popular in recent years. Hence, exclusive enteral nutrition in paediatric Crohn’s disease is the only nutritional intervention currently recommended as a first-line therapy. Other nutritional interventions or specific diets including the Specific Carbohydrate Diet (SCD), the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diet and, most recently, the Mediterranean diet have shown strong anti-inflammatory properties and show promise for improving disease symptoms. More work is required to evaluate the role of individual food compounds and complex nutritional interventions with the potential to decrease inflammation as a means of prevention and management of IBD.

Dietary phosphate exacerbates intestinal inflammation in experimental colitis

The recent widespread consumption of Western diets and food additives worldwide is associated with excessive inorganic phosphate intake. However, researchers have known little about the impact of dietary phosphate intake on the development of inflammatory bowel disease to date. In this study, we investigated the effects of dietary phosphate on intestinal inflammation in experimental colitis. Sprague-Dawley rats were fed different phosphate diets (0.5%, 1.0% and 1.5% phosphate) with or without dextran sulfate sodium. For in vitro study, the effects of phosphate on proinflammatory cytokine induction and reactive oxygen species production in RAW264.7 macrophage were examined. Dietary phosphate exacerbated intestinal inflammation in experimental colitis in a dose-dependent manner, as assessed by the clinical disease activity score, colon length, and histology. Furthermore, the high phosphate diet increased myeloperoxidase activity and proinflammatory cytokine mRNA expression through the activation of nuclear factor κB in the inflamed colon. In addition, high phosphate loading in RAW264.7 cells directly enhanced reactive oxygen species production and proinflammatory cytokine gene expression. Our results demonstrated that the high phosphate diet exacerbated intestinal inflammation in experimental colitis. These findings have important therapeutic implications for inflammatory bowel disease patients.

Dietary Protein and Amino Acid Supplementation in Inflammatory Bowel Disease Course: What Impact on the Colonic Mucosa?

Inflammatory bowel diseases (IBD), after disease onset, typically progress in two cyclically repeated phases, namely inflammatory flare and remission, with possible nutritional status impairment. Some evidence, either from epidemiological, clinical, and experimental studies indicate that the quantity and the quality of dietary protein consumption and amino acid supplementation may differently influence the IBD course according to the disease phases. For instance, although the dietary protein needs for mucosal healing after an inflammatory episode remain undetermined, there is evidence that amino acids derived from dietary proteins display beneficial effects on this process, serving as building blocks for macromolecule synthesis in the wounded mucosal area, energy substrates, and/or precursors of bioactive metabolites. However, an excessive amount of dietary proteins may result in an increased intestinal production of potentially deleterious bacterial metabolites. This could possibly affect epithelial repair as several of these bacterial metabolites are known to inhibit colonic epithelial cell respiration, cell proliferation, and/or to affect barrier function. In this review, we present the available evidence about the impact of the amount of dietary proteins and supplementary amino acids on IBD onset and progression, with a focus on the effects reported in the colon.

Animal Models for the Study of the Relationships between Diet and Obesity: A Focus on Dietary Protein and Estrogen Deficiency

Obesity is an increasing major public health concern asking for dietary strategies to limit weight gain and associated comorbidities. In this review, we present animal models, particularly rats and mice, which have been extensively used by scientists to understand the consequences of diet quality on weight gain and health. Notably, modulation of dietary protein quantity and/or quality has been shown to exert huge effects on body composition homeostasis through the modulation of food intake, energy expenditure, and metabolic pathways. Interestingly, the perinatal window appears to represent a critical period during which the protein intake of the dam can impact the offspring’s weight gain and feeding behavior. Animal models are also widely used to understand the processes and mechanisms that contribute to obesity at different physiological and pathophysiological stages. An interesting example of such aspect is the situation of decreased estrogen level occurring at menopause, which is linked to weight gain and decreased energy expenditure. To study metabolic disorders associated with such situation, estrogen withdrawal in ovariectomized animal models to mimic menopause are frequently used. According to many studies, clear species-specific differences exist between rats and mice that need to be taken into account when results are extrapolated to humans.

Lipocalin 2 prevents intestinal inflammation by enhancing phagocytic bacterial clearance in macrophages

Lipocalin 2 (Lcn2), also called neutrophil gelatinase B-associated lipocalin (NGAL), is an anti-microbial peptide originally identified in neutrophil granules. Although Lcn2/NGAL expression is increased in the inflamed intestinal tissues of patients with inflammatory bowel disease, the role of Lcn2/NGAL in the development of intestinal inflammation remains unclear. Here we investigated the role of Lcn2/NGAL in intestinal inflammation using a spontaneous mouse colitis model, interleukin-10 knock out (IL-10 KO) mice. Lcn2 expression in the colonic tissues of IL-10 KO mice increased with the development of colitis. Lcn2/IL-10 double-KO mice showed a more rapid onset and development of colitis compared to IL-10 KO mice. Lcn2 enhanced phagocytic bacterial clearance in macrophages in vitro after infection with Escherichia coli. Transfer of Lcn2-repleted macrophages prevented the development of colitis in Lcn2/IL-10 double-KO mice in vivo. Our findings revealed that Lcn2 prevents the development of intestinal inflammation. One crucial factor seems to be the enhancement of phagocytic bacterial clearance in macrophages by Lcn2.

Faecal calprotectin: factors affecting levels and its potential role as a surrogate marker for risk of development of Crohn's Disease

Background

Faecal calprotectin (FC) is one of the most widely used non-invasive tests for the diagnosis and assessment of Crohn’s disease (CD) activity. Despite this, factors other than disease activity which affect levels have not been extensively reviewed. This is of importance when using FC in the diagnostic setting but also may be of utility in studying the aetiology of disease.

Objectives

Our review outlines environmental risk factors that affect FC levels influencing diagnostic accuracy and how these may be associated with risk of developing CD. FC as a surrogate marker could be used to validate risk factors established in case control studies where prospective studies are not feasible. Proof of this concept is provided by our identification of obesity as being associated with elevated FC, our subsequent confirmation of obesity as risk factor for CD and the subsequent verification in prospective studies, as well as associations of lack of physical activity and dietary fibre intake with elevated FC levels and their subsequent confirmation as risk factors in prospective studies.

Conclusion

We believe that FC is likely to prove a useful surrogate marker for risk of developing CD. This review has given a theoretical basis for considering the epidemiological determinants of CD which to date has been missing.