Fat composition may be a clue to explain the primary therapeutic effect of enteral nutrition in Crohn's disease: results of a double blind randomised multicentre European trial

British Dietetic Association evidence-based guidelines for the dietary management of Crohn's disease in adults

BACKGROUND

Crohn's disease is a debilitating chronic inflammatory bowel disease. Appropriate use of diet and nutritional therapy is integral to the overall management strategy of Crohn's disease. The aim was to develop evidence-based guidelines on the dietary management of Crohn's disease in adults.

METHODS

Questions relating to the dietary management of Crohn's disease were developed. These included the roles of enteral nutrition to induce remission, food re-introduction diets to structure food re-introduction and maintain remission, and dietary management of stricturing disease, as well as whether probiotics or prebiotics induce or maintain remission. A comprehensive literature search was conducted and relevant studies from January 1985 to November 2009 were identified using the electronic database search engines CINAHL, Cochrane Library, EMBASE, MEDLINE, Scopus and Web of Science. Evidence statements, recommendations, practical considerations and research recommendations were developed.

RESULTS

Fifteen research papers were critically appraised and the evidence formed the basis of these guidelines. Although corticosteroids appear to be more effective, enteral nutrition (elemental or non-elemental) can be offered as an alternative option to induce disease remission. After a course of enteral nutrition, food re-introduction diets may be useful to structure food re-introduction and help maintain disease remission. Dietary fibre is contraindicated in the presence of strictures as a result of the risk of mechanical obstruction. The use of probiotics and prebiotics is not currently supported.

CONCLUSIONS

As an alternative to corticosteroids, evidence supports enteral nutrition to induce disease remission. Food re-introduction diets provide structure to food re-introduction and help maintain disease remission. These guidelines aim to reduce variation in clinical practice.

Use of exclusive enteral nutrition in adults with Crohn's disease: a review

Exclusive enteral nutrition (EEN) is well-established as a first line therapy instead of corticosteroid (CS) therapy to treat active Crohn's disease (CD) in children. It also has been shown to have benefits over and above induction of disease remission in paediatric populations. However, other than in Japanese populations, this intervention is not routinely utilised in adults. To investigate potential reasons for variation in response between adult studies of EEN and CS therapy. The Ovid database was searched over a 6-mo period. Articles directly comparing EEN and CS therapy in adults were included. Eleven articles were identified. EEN therapy remission rates varied considerably. Poor compliance with EEN therapy due to unpalatable formula was an issue in half of the studies. Remission rates of studies that only included patients with previously untreated/new CD were higher than studies including patients with both existing and new disease. There was limited evidence to determine if disease location, duration of disease or age of diagnosis affected EEN therapy outcomes. There is some evidence to support the use of EEN as a treatment option for a select group of adults, namely those motivated to adhere to an EEN regimen and possibly those newly diagnosed with CD. In addition, the use of more palatable formulas could improve treatment compliance.

Anti-inflammatory effect of elemental diets with different fat composition in experimental colitis

The aim of the present study was to evaluate the effectiveness of two isoenergetic elemental formulae with different fat content in the rat model of trinitrobenzene sulphonic acid (TNBS) colitis that mimics human inflammatory bowel disease. A total of forty-five male Wistar rats were assigned to five groups: (1) control group; (2) TNBS-induced colitis group; (3) TNBS-induced colitis group fed a long-chain TAG (LCT)-rich diet; (4) TNBS-induced colitis group fed a medium-chain TAG (MCT)-rich diet; (5) TNBS-induced colitis group fed a baseline diet and administered infliximab. Nutritional management lasted 12 d before and 4 d after rectal administration of TNBS. Subsequently, the rats were killed, and colonic tissue samples were collected for the assessment of histology, inflammation and oxidative stress. The MCT-rich diet decreased IL-6, IL-8 and intercellular adhesion molecule-1 (ICAM-1) levels and glutathione S-transferase (GST) activity, while the LCT-rich diet reduced only ICAM-1 levels and GST activity (P< 0·05). Neither elemental formula affected IL-10 levels. Infliximab reduced IL-8 and ICAM-1 levels and GST activity and increased IL-10 levels (P< 0·05). No significant differences were detected in oxidative stress. Histological damage scores differed significantly only between the control and the TNBS-induced colitis group. A MCT-rich formula seems to exert stronger anti-inflammatory effects than a LCT-rich formula in TNBS colitis.

Nutritional management of Crohn's disease

Nutritional care and therapy forms an integral part of the management of patients with Crohn's disease (CD). Nutritional deficiencies result from reduced oral intake, malabsorption, medication side effects and systemic inflammation due to active disease. Enteral nutrition has a role in support for the malnourished patient, as well as in primary therapy to induce and maintain remission. The use of parenteral nutrition in CD is mainly limited to the preoperative setting or for patients with intestinal failure, but does not offer any additional advantage over EN in disease control. Dietary modifications, including elimination-reintroduction diets and a low fermentable, oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet may improve symptoms but there are currently no data to suggest that these approaches have any role in the induction or maintenance of remission.

Nutrition and diet in inflammatory bowel disease

PURPOSE OF REVIEW

Diet is known to have a major role in the expression of inflammatory bowel disease (IBD). The role of dietary interventions and enteral nutrition in the management of IBD remains unelucidated. This study was to review the current evidence for dietary risk factors for the development of IBD and the efficacies of dietary and enteral interventions.

RECENT FINDINGS

High dietary intakes of total fats, polyunsaturated fatty acids, omega-6 fatty acids, and meat are associated with an increased risk of Crohn's disease and ulcerative colitis. Further prospective studies are required to confirm these observations. Among various dietary interventions, none has shown striking efficacy. Meta-analyses have shown enteral nutrition to be inferior to corticosteroids in adults with active Crohn's disease. However, in children, a meta-analysis has shown no significant difference in the remission rates between enteral nutrition and corticosteroid therapy. Although the evidence level is not striking, enteral nutrition may be useful for maintaining remission in patients with quiescent Crohn's disease.

SUMMARY

Dietary risk factors for IBD and the therapeutic benefit of dietary and enteral interventions need to be confirmed by further well designed studies in large cohorts of patients.

Polyunsaturated fatty acids in inflammatory bowel diseases: a reappraisal of effects and therapeutic approaches

Recent epidemiological studies highlight the key role of the type of consumed unsaturated fatty acid and the development of ulcerative colitis (UC). We aimed to review the potential mechanisms behind the antiinflammatory effects of unsaturated fatty acids on intestinal inflammation, to discuss their potential limitations, and to propose a new reappraisal of polyunsaturated fatty acids (PUFAs) in the pathophysiology of inflammatory bowel disease (IBD). A literature search using PubMed was carried out to identify relevant studies (basic science, epidemiological studies, or clinical trials) with unsaturated fatty acids and IBD. Only articles published in English were included. IBD patients exhibit an altered lipid metabolism. While in vitro and in vivo studies have demonstrated the antiinflammatory properties of n-3 polyunsaturated fatty acids in experimental models IBD, results of clinical trials have been disappointing. In addition, the impact of fatty acid on innate immunity as an alternative therapeutic approach is explored. This may offer insight into therapeutic avenues for designing n-3 PUFA diet therapy for IBD.

Impact of environmental and dietary factors on the course of inflammatory bowel disease

Besides their possible effects on the development of inflammatory bowel disease (IBD), some environmental factors can modulate the clinical course of both ulcerative colitis (UC) and Crohn’s disease (CD). This review is mainly devoted to describing the current knowledge of the impact of some of these factors on the outcome of IBD, with special emphasis on smoking and diet. Although the impact of smoking on the susceptibility to develop CD and UC is firmly established, its influence on the clinical course of both diseases is still debatable. In CD, active smoking is a risk factor for postoperative recurrence. Beyond this clinical setting, smoking cessation seems to be advantageous in those CD patients who were smokers at disease diagnosis, while smoking resumption may be of benefit in ex-smokers with resistant UC. The role of dietary habits on the development of IBD is far from being well established. Also, food intolerances are very frequent, but usually inconsistent among IBD patients, and therefore no general dietary recommendations can be made in these patients. In general, IBD patients should eat a diet as varied as possible. Regarding the possible therapeutic role of some dietary components in IBD, lessons should be drawn from the investigation of the primary therapeutic effect of enteral nutrition in CD. Low-fat diets seem to be particularly useful. Also, some lipid sources, such as olive oil, medium-chain triglycerides, and perhaps omega-3 fatty acids, might have a therapeutic effect. Fermentable fiber may have a role in preventing relapses in inactive UC.

An update of the role of nutritional therapy in the management of Crohn's disease

Crohn's disease is an increasingly global health concern. Currently without a cure, it significantly alters the quality of life of Crohn's disease sufferers and places a heavy financial burden on the community. Recent reports show that the rising prevalence of Crohn's disease is no longer confined to Western countries, with considerable increases seen particularly in Asia. Nutritional problems are often associated with Crohn's disease, most notably in the paediatric population, with underweight and stunting commonly seen at presentation. In addition, linear growth retardation and pubertal delay can also manifest in these younger patients. Therefore, exclusive enteral nutrition has been used as a therapeutic option to treat Crohn's disease, in part to address the nutritional complications of the disease. Exclusive enteral nutrition can improve nutrition as well as induce remission at a rate equivalent to corticosteroids. It is safe particularly with long-term use and can induce mucosal healing, considered the gold standard for therapy, at a rate superior to corticosteroids. Exclusive enteral nutrition has thus become the preferred therapeutic option in many centres for the treatment of paediatric Crohn's disease. This review discusses the role of exclusive enteral nutrition as a therapeutic option for the treatment of Crohn's disease, as well as the latest findings into its mechanisms of action.

Partial replacement of ω-6 fatty acids with medium-chain triglycerides, but not olive oil, improves colon cytokine response and damage in experimental colitis

BACKGROUND

Soybean oil is rich in ω-6 fatty acids, which are associated with higher incidence and more severe cases of inflammatory bowel diseases. The authors evaluated whether partial replacement of soybean oil by medium-chain triglycerides (MCTs) or olive oil influenced the incidence and severity of experimental ulcerative colitis by using different parenteral lipid emulsions (LEs).

METHODS

Wistar rats (n = 40) were randomized to receive parenteral infusion of the following LE: 100% soybean oil (SO), 50% MCT mixed with 50% soybean oil (MCT/SO), 80% olive oil mixed with 20% soybean oil (OO/SO), or saline (CC). After 72 hours of infusion, acetic acid experimental colitis was induced. After 24 hours, colon histology and cytokine expression were analyzed.

RESULTS

SO was not significantly associated with overall tissue damage. MCT/SO was not associated with necrosis (P < .005), whereas OO/SO had higher frequencies of ulcer and necrosis (P < .005). SO was associated with increased expression of interferon-γ (P = .005) and OO/SO with increased interleukin (IL)-6 and decreased tumor necrosis factor-α expression (P < .05). MCT/SO appeared to decrease IL-1 (P < .05) and increase IL-4 (P < .001) expression.

CONCLUSIONS

Parenteral SO with high concentration of ω-6 fatty acids was not associated with greater tissue damage in experimental colitis. SO partial replacement with MCT/SO decreased the frequency of histological necrosis and favorably modulated cytokine expression in the colon; however, replacement with OO/SO had unfavorable effects.

The role of nutrition in the etiology of inflammatory bowel disease

Many foods have been implicated in theories about the etiology of inflammatory bowel disease. While evidence has accumulated that nutritional factors as part of overall lifestyle changes may play a role in the growing incidence, no specific dietary recommendations except the promotion of breastfeeding can currently be given to decrease the risk of developing Crohn's disease or ulcerative colitis. For the treatment of Crohn's disease in children and adolescents, however, enteral feeding with a semi-elemental diet seems to be as effective as corticosteroids in inducing and maintaining remission. In the meta-analyses, advantages of one formula over the other are evened out, and more research is warranted into the anti-inflammatory properties of different nutrients, such as polyunsaturated fatty acids, butyrate, glutamine, and cytokines, such as transforming growth factors-beta. Unfortunately, for practical reasons, nutritional therapy remains underutilized, even though pediatric patients are most vulnerable to the harmful effects of nutrient deficiencies on growth, pubertal development, and bone health. There is hope that in the future the new field of nutrigenomics may enable physicians to more accurately tailor a specific diet to the patient genotype.

New insights into the role of fatty acids in the pathogenesis and resolution of inflammatory bowel disease

Dietary and endogenously modified lipids modulate inflammation by functioning as intra- and intercellular signaling molecules. Proinflammatory lipid mediators such as the eicosanoids compete against the signaling actions of newly discovered modified fatty acids that act to resolve inflammation. In inflammatory bowel disease, multiple aberrancies in lipid metabolism have been discovered, which shed further light on the pathogenesis of intestinal inflammation. Mechanisms by which lipids modulate inflammation, abnormalities of lipid metabolism in the setting of inflammatory bowel disease, and potential therapeutic application of lipid derivatives in this setting are discussed.

Nutrition in inflammatory bowel disease

The diet of industrialized nations may contribute to the pathogenesis of both ulcerative colitis (UC) and Crohn disease (CD). Malnutrition is relatively unusual in UC, but in CD, which often affects the small intestine, it is frequent and may be severe. Nutrition support is therefore frequently indicated. First principles of artificial nutrition can be applied effectively using the gut whenever possible. Parenteral nutrition is generally required only in those with short bowel syndrome. An increasing literature (especially in pediatrics) favors the use of defined exclusive enteral nutrition (EN) in the primary treatment of active CD. Controlled trials are, however, lacking, and recommendations are accordingly not of the highest rank. It appears that in this context, simple polymeric regimens are usually sufficient, and there is currently insufficient evidence to make a strong recommendation for disease-specific feeds. In the maintenance of remission in CD, controlled data demonstrate that defined EN reduces the risk of relapse requiring steroid treatment. There are no data in support of primary nutrition therapy in UC either in management of the acute flare or in maintenance. In conclusion, nutrition therapy in adults with inflammatory bowel disease is probably both undervalued and underused, but the evidence base needs to be strengthened to confirm its efficacy, determine better those patients most likely to benefit, and optimize the regimens to be employed.

Existing dietary guidelines for Crohn's disease and ulcerative colitis

Patients with inflammatory bowel disease (IBD) often question their doctors about diet. The objectives of this article are to provide clinicians with existing dietary advice by presenting the dietary information proposed by medical societies in the form of clinical practice guidelines as it relates to IBD; listing dietary guidelines from patient-centered IBD-related organizations; and creating a new 'global practice guideline' that attempts to consolidate the existing information regarding diet and IBD. The dietary suggestions derived from sources found in this article include nutritional deficiency screening, avoiding foods that worsen symptoms, eating smaller meals at more frequent intervals, drinking adequate fluids, avoiding caffeine and alcohol, taking vitamin/mineral supplementation, eliminating dairy if lactose intolerant, limiting excess fat, reducing carbohydrates and reducing high-fiber foods during flares. Mixed advice exists regarding probiotics. Enteral nutrition is recommended for Crohn's disease patients in Japan, which differs from practices in the USA.

Dietary and nutritional considerations for inflammatory bowel disease

Nutritional assessment and dietary advice are fundamental to inflammatory bowel disease (IBD) patient management and all patients should have access to a dietitian. Newly diagnosed patients often think that their pre-illness diet has contributed to the development of their IBD. However, epidemiological evidence to support diet as a risk factor is lacking. How the diet contributes to the gastrointestinal microbiota is interesting, although the role is not yet clearly defined. Nutritional problems in IBD are common. Malnutrition occurs in up to 85% of patients and weight loss affects up to 80% of patients with Crohn's disease and 18-62% of patients with ulcerative colitis. Nutritional deficiencies are prevalent, particularly in relation to anaemia and osteoporosis. Intestinal strictures can be problematic in Crohn's disease and limiting fibrous foods that may cause a mechanical obstruction in the gastrointestinal tract is helpful. Patients often explore dietary exclusion to alleviate symptoms but such changes may be self-directed or inappropriately advised and can lead to further nutritional deficiencies. Some patients experience concurrent functional symptoms (e.g. abdominal bloating, abdominal pain, flatulence and diarrhoea) that can significantly affect quality of life. Recently, a group of poorly absorbed carbohydrates that occur naturally in the diet called fermentable oligo-, di-, mono-saccharides and polyols have been associated with functional symptoms by intestinal bacterial fermentation leading to rapid gas production, and an osmotic effect increasing fluid delivery to the colon. Emerging evidence indicates that a diet low in fermentable oligo-, di-, mono-saccharides and polyols can alleviate functional symptoms in IBD.

Nutritional consequences and nutrition therapy in Crohn's disease

75% of hospital patients with Crohn's disease (CD) suffer from malnutrition and one third of CD patients have a body mass index below 20. Inflammatory bowel diseases (IBD) patients have many vitamin and nutrient deficiencies which can lead to important consequences such as hyperhomocysteinemia which is associated with a higher risk of thromboembolic disease. Nutritional deficiencies in IBD patients are the result of insufficient intake, malabsorption and protein-losing enteropathy as well as the metabolic distubances directly induced by the chronic disease and its treatments, in particular corticosteroids. Screening for nutritional deficiencies in chronic disease patients is warranted. Managing the deficiencies involves simple nutritional guidelines, vitamin supplements, and nutritional support in the worst cases, in particular in children in order to limit the impact of IBD on growth. In active CD, enteral nutrition is the first line therapy in children and should be used as sole therapy in adults mainly when treatment with corticosteroids is not feasible.

Risk factors for metabolic bone disease in Crohn's disease patients

BACKGROUND

The aim was to evaluate the presence of metabolic bone disease (MBD) in patients with Crohn's disease (CD) and to identify potential etiologic factors.

METHODS

The case-control study included 99 patients with CD and 56 controls with a similar age and gender distribution. Both groups had dual-energy x-ray absorptionmetry and a nutritional evaluation. Single nucleotide polymorphisms at the IL1, TNF-α, LTα, and IL-6 genes were analyzed in patients only. Statistical analysis was performed using SPSS software.

RESULTS

The prevalence of MBD was significantly higher in patients (P = 0.006). CD patients with osteoporosis were older (P < 0.005), small bowel involvement and surgical resections were more frequent (P < 0.005), they more often exhibited a penetrating or stricturing phenotype (P < 0.05), duration of disease over 15 years (P < 0.005), and body mass index (BMI) under 18.5 kg/m(2) (P < 0.01) were more often found. No association was found with steroid use. Patients with a Z-score < -2.0 more frequently had chronic active disease (P < 0.05). With regard to diet, low vitamin K intake was more frequent (P = 0.03) and intake of total, monounsaturated, and polyunsaturated fat was higher in patients with Z-score < -2.0 (P < 0.05). With respect to genetics, carriage of the polymorphic allele for LTα252 A/G was associated with a higher risk of osteoporosis (P = 0.02). Regression analysis showed that age over 40 years, chronic active disease, and previous colonic resections were independently associated with the risk of developing MBD.

CONCLUSIONS

The prevalence of MBD was significantly higher in CD patients. Besides the usual risk factors, we observed that factors related to chronic active and long-lasting disease increased the risk of MBD.

Combining nutrition, food science and engineering in developing solutions to Inflammatory bowel diseases--omega-3 polyunsaturated fatty acids as an example

The Inflammatory bowel diseases, Crohn's disease and ulcerative colitis, are debilitating conditions, characterised by lifelong sensitivity to certain foods, and often a need for surgery and life-long medication. The anti-inflammatory effects of long chain omega-3 polyunsaturated acids justify their inclusion in enteral nutrition formulas that have been associated with disease remission. However, there have been variable data in clinical trials to test supplementary omega-3 polyunsaturated fatty acids in inducing or maintaining remission in these diseases. Although variability in trial design has been suggested as a major factor, we suggest that variability in processing and presentation of the products may be equally or more important. The nature of the source, and rapidity of getting the fish or other food source to processing or to market, will affect the percentage of the various fatty acids, possible presence of heavy metal contaminants and oxidation status of the various fatty acids. For dietary supplements or fortified foods, whether the product is encapsulated or not, whether storage is under nitrogen or not, and length of time between harvest, processing and marketing will again profoundly affect the properties of the final product. Clinical trials to test efficacy of these products in IBD to date have utilised the relevant skills of pharmacology and gastroenterology. We suggest that knowledge from food science, nutrition and engineering will be essential to establish the true role of this important group of compounds in these diseases.

Fat intake interacts with polymorphisms of Caspase9, FasLigand and PPARgamma apoptotic genes in modulating Crohn's disease activity

BACKGROUND & AIMS

Crohn's disease (CD) is a multifactorial disease where resistance to apoptosis is one major defect. Also, dietary fat intake has been shown to modulate disease activity. We aimed to explore the interaction between four single nucleotide polymorphisms (SNPs) in apoptotic genes and dietary fat intake in modulating disease activity in CD patients.

METHODS

Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP) techniques were used to analyze Caspase9+93C/T, FasLigand-843C/T, Peroxisome Proliferator-Activated Receptor gamma+161C/T and Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNPs in 99 patients with CD and 116 healthy controls. Interactions between SNPs and fat intake in modulating disease activity were analyzed using regression analysis.

RESULTS

None of the polymorphisms analyzed influenced disease susceptibility and/or activity, but a high intake of total, saturated and monounsaturated fats and a higher ratio of n-6/n-3 polyunsaturated fatty acids(PUFA), was associated with a more active phenotype (p < 0.05). We observed that the detrimental effect of a high intake of total and trans fat was more marked in wild type carriers of the Caspase9+93C/T polymorphism [O.R(95%CI) 4.64(1.27-16.89) and O.R(95%CI) 4.84(1.34-17.50)]. In the Peroxisome Proliferator-Activated Receptor gamma Pro12Ala SNP, we also observed that a high intake of saturated and monounsaturated fat was associated to a more active disease in wild type carriers [OR(95%CI) 4.21(1.33-13.26) and 4.37(1.52-12.51)]. Finally, a high intake of n-6 PUFA was associated with a more active disease in wild type carriers for the FasLigand-843C/T polymorphism [O.R(95%CI) 5.15(1.07-24.74)].

CONCLUSIONS

To our knowledge, this is the first study to disclose a synergism between fat intake and SNPs in apoptotic genes in modulating disease activity in CD patients.

Crohn's disease as an immunodeficiency

The pathogenesis of Crohn's disease (CD) has widely been regarded as the consequence of a dysregulated T-cell-mediated response to intestinal microbes, and the majority of the worldwide research effort has focused on characterizing and treating the chronic inflammatory phase of the disease. However, recent molecular biological and clinical investigations indicate that CD is actually a primary immunodeficiency. At first counter-intuitive, the apparent paradox of a pathogenic innate immune defect can be linked mechanistically to the granulomatous chronic inflammation characteristic of the disease. Genome-wide association studies have corroborated the involvement of innate immune dysfunction in the pathogenesis of CD, but less than 20% of the heritable risk is accounted for. By contrast, in vitro and in vivo stimulation of the immune system has highlighted novel areas of interest that may lead to the development of targeted therapeutic and diagnostic tools.

Nutritional considerations in pediatric inflammatory bowel disease

Nutrition is a critical part of the management of inflammatory bowel disease (IBD) in children and adults. Malnutrition and micronutrient deficiencies are common at the time of diagnosis and may persist throughout the course of the disease. There are a number of similarities with regards to the nutritional complications and the approach to nutritional management in IBD in both children and adults, but there are also important differences. Growth failure, pubertal delay and the need for corticosteroid-sparing regimens are of higher importance in pediatrics. In the pediatric population, exclusive enteral nutrition may be equivalent to corticosteroids in inducing remission in acute Crohn's disease, and may have benefits over corticosteroids in children. Adherence with exclusive enteral nutrition is better in children than in adults. Iron deficiency anemia is an important problem for adults and children with IBD. Intravenous iron administration may be superior to oral iron supplementation. Ensuring adequate bone health is another critical component of nutritional management in IBD, but guidelines for screening and therapeutic interventions for low bone mineral density are lacking in children.

Does evidence exist to include dietary therapy in the treatment of Crohn's disease?

Prescription drugs and surgery are two common medical therapies for Crohn's disease (CD), an inflammatory bowel disease that affects the GI tract. Unfortunately, certain drugs can cause serious side effects, and surgeries must often be repeated. No diet has been established to alleviate the pain and suffering of CD patients. This is curious given the fact that a higher prevalence of food sensitivities exist in this population of patients, and enteral nutrition is not only the first-line of therapy in Japan, but a known research method used to place the majority of CD patients into remission. Although not all patients respond equally to diet, many simply remove symptom-provoking foods, such as dairy, wheat, corn and certain fruits and vegetables. We suggest assisting these patients in their self-assessment of irritating and symptom-provoking foods by educating them in the use of a food-symptom diary followed by a customized elimination diet trialed for 2-4 weeks to determine if there is any benefit to the individual patient.

Dietary factors in chronic inflammation: food tolerances and intolerances of a New Zealand Caucasian Crohn's disease population

Diet is known to play a major role in the symptoms of the inflammatory bowel disease, Crohn's disease (CD). Although no single diet is appropriate to all individuals, most CD patients are aware of foods that provide adverse or beneficial effects. This study seeks to categorise foods in relation to their effects on symptoms of CD, in a New Zealand Caucasian population. Four hundred and forty-six subjects from two different centres in New Zealand were recruited into the study. An extensive dietary questionnaire (257 food items in 15 groups) recorded self-reported dietary tolerances and intolerances. Across each of the food groups, there were statistically significant differences among responses to foods. A two-dimensional graphical summary enabled stratification of foods according to the probability that they will be either beneficial or detrimental. A small number of foods are frequently considered to be beneficial, including white fish, salmon and tuna, gluten-free products, oatmeal, bananas, boiled potatoes, sweet potatoes (kumara), pumpkin, soya milk, goat's milk and yoghurt. Foods that are typically considered detrimental include grapefruit, chilli or chilli sauce, corn and corn products, peanuts, cream, salami, curried foods, cola drinks, high energy drinks, beer, and red wine. For a number of the food items, the same item that was beneficial for one group of subjects was detrimental to others; in particular soya milk, goat's milk, yoghurt, oatmeal, kiwifruit, prunes, apple, broccoli, cauliflower, linseed, pumpkin seed, sunflower seed, ginger and ginger products, beef, lamb, liver, and oily fish. It was not possible to identify a specific group of food items that should be avoided by all CD patients. The wide range of detrimental items suggests that dietary maintenance of remission is likely to be difficult, and to exclude a substantial number of foods. Personalised diets may be especially important to these individuals.

Cholesterol metabolism in active Crohn's disease

Hypocholesterolemia has been investigated as a typical feature of critical illness and is connected with poor prognosis. Crohn's disease is an inflammatory process and is associated with several metabolic disturbances. In recent decades clinical studies have established a link between lipid metabolism and systemic inflammation. In our study we examined the serum profile of cholesterol (total cholesterol, LDL- and HDL-cholesterol) and changes in the cholesterol absorption/synthesis process by determination of plasma non-cholesterol sterol (squalene, lathosterol, campesterol, sitosterol) concentrations. Serum concentrations of total cholesterol, LDL- and HDL-cholesterol and non-cholesterol sterols were evaluated in 24 patients with active Crohn's disease during a period of 28 days. We detected lower serum levels of total cholesterol (P < 0.001), LDL- and HDL-cholesterol (P < 0.05) in the patients with active Crohn's disease than in the control group. In addition, the patients had significantly lower plasma levels of lathosterol (P < 0.001) and higher concentrations of squalene, although without significant differences. A significant decrease of campesterol plasma levels (P < 0.001) was detected, but lower plasma concentrations of sitosterol were without statistical significance. The active phase of Crohn's disease is characterized by altered metabolism of lipids, mainly of cholesterol. Our results show abnormalities in plasma concentrations of non-cholesterol sterols and provide evidence that the process of cholesterol synthesis and absorption is altered in active Crohn's disease.

Fatty acids, IL6, and TNFalpha polymorphisms: an example of nutrigenetics in Crohn's disease

OBJECTIVES

The aim of this work was to study the interaction between genetic polymorphisms (single-nucleotide polymorphisms, SNPs) of pro- and anti-inflammatory cytokines and fat intake on the risk of developing Crohn's disease (CD) or modifying disease activity.

METHODS

Seven SNPs in interleukin 1 (IL1), tumor necrosis factor alpha (TNFalpha), lymphotoxin alpha (LTalpha), and IL6 genes were analyzed in 116 controls and 99 patients with CD. The type of fat intake was evaluated, and the interaction between SNPs and dietary fat in modulating disease activity was analyzed.

RESULTS

Individuals who were homozygous for the IL6-174G/C polymorphism had a six-fold higher risk for CD (odds ratio (OR)=6.1; 95% confidence interval (95% CI)=1.9-19.4), whereas the TT genotype on the TNFalpha-857C/T polymorphism was associated with more active disease (OR=10.4; 95% CI=1.1-94.1). A high intake of total, saturated, and monounsaturated fats, as well as a higher ratio of n-6/n-3 polyunsaturated fatty acid (PUFA), was associated with a more active phenotype (P<0.05). Furthermore, there was an interaction between dietary fat intake and SNPs, with a high intake of saturated and monounsaturated fats being associated with active disease, mainly in patients carrying the variant alleles of the 857 TNFalpha polymorphism (OR=6.0, 95% CI=1.4-26.2; OR=5.17; 95% CI=1.4-19.2, respectively) and the 174 IL6 polymorphism (OR=2.95; 95% CI=1.0-9.1; OR=3.21; 95% CI=1.0-10.4, respectively). Finally, low intake of n-3 PUFA and high n-6/n-3 PUFA ratio in patients with the TNFalpha 857 polymorphism were associated with higher disease activity (OR=3.6; 95% CI=1.0-13.0; OR=5.92; 95% CI=1.3-26.5, respectively).

CONCLUSIONS

These results show that different types of fat may interact with cytokine genotype, modulating disease activity.

Importance of nutrition in inflammatory bowel disease

Inflammatory bowel disease (IBD) results from the interaction between an individual's immune response and precipitant environmental factors, which generate an anomalous chronic inflammatory response in those who are genetically predisposed. Various feeding practices have been implicated in the origin of IBD based on epidemiological observations in developed countries, but we do not have solid evidence for the etiological role played by specific food types. IBD is associated with frequent nutritional deficiencies, the pattern and severity of which depends on the extent, duration and activity of the inflammation. Nutritional support allows these deficiencies in calories, macro- and micro-nutrients to be rectified. Enteral nutrition is also a primary therapy for IBD, especially for Crohn's disease, as it allows the inflammatory activity to be controlled, kept in remission, and prevents or delays the need for surgery. Nutritional support is especially important in childhood IBD as an alternative to pharmacological treatment. This report discusses the complex relationship between diet and IBD.

Review article: diet and inflammatory bowel disease--epidemiology and treatment

BACKGROUND

Diet is thought to have an important role in the immunopathogenesis and treatment of inflammatory bowel disease (IBD).

AIM

To identify dietary constituents as risk factors for development of IBD and the therapeutic efficacy of dietary modifications or enteral nutrition in IBD.

METHODS

The Medline and the Cochrane Library were searched for clinical trials and meta-analyses in the scope of diet and nutrition in IBD.

RESULTS

There are many studies in small cohorts of patients that claim that intake of certain diet constituents like fat, refined sugar, fruits, vegetables and fibre affect the expression of IBD. These are often compromised by insufficient data or methodological limitations and do not provide unequivocal evidence to incriminate any particular dietary factor. Among various dietary interventions, none has shown striking efficacy with the possible exception of complete enteral nutrition. Enteral nutrition appears effective in both active and quiescent Crohn's disease (CD), but independent meta-analyses have shown enteral nutrition to be inferior to corticosteroids in the management of active CD, when assessed on an intention-to-treat basis.

CONCLUSIONS

The current levels of knowledge concerning dietary risk factors for IBD, and the therapeutic efficacy of dietary and nutritional interventions need to be supported by well-designed trials in large cohorts of patients.

Nutritional status and nutritional therapy in inflammatory bowel diseases

Underweight and specific nutrient deficiencies are frequent in adult patients with inflammatory bowel disease (IBD). In addition, a significant number of children with IBD, especially Crohn’s disease (CD) have impaired linear growth. Nutrition has an important role in the management of IBD. In adults with CD, enteral nutrition (EN) is effective in inducing clinical remission of IBD, although it is less efficient than corticosteroids. Exclusive EN is an established primary therapy for pediatric CD. Limited data suggests that EN is as efficient as corticosteroids for induction of remission. Additional advantages of nutritional therapy are control of inflammation, mucosal healing, positive benefits to growth and overall nutritional status with minimal adverse effects. The available evidence suggests that supplementary EN may be effective also for maintenance of remission in CD. More studies are needed to confirm these findings. However, EN supplementation could be considered as an alternative or as an adjunct to maintenance drug therapy in CD. EN does not have a primary therapeutic role in ulcerative colitis. Specific compositions of enteral diets-elemental diets or diets containing specific components-were not shown to have any advantage over standard polymeric diets and their place in the treatment of CD or UC need further evaluation. Recent theories suggest that diet may be implicated in the etiology of IBD, however there are no proven dietary approaches to reduce the risk of developing IBD.

Importance of nutrition in inflammatory bowel disease

Inflammatory bowel disease (IBD) results from the interaction between an individual’s immune response and precipitant environmental factors, which generate an anomalous chronic inflammatory response in those who are genetically predisposed. Various feeding practices have been implicated in the origin of IBD based on epidemiological observations in developed countries, but we do not have solid evidence for the etiological role played by specific food types. IBD is associated with frequent nutritional deficiencies, the pattern and severity of which depends on the extent, duration and activity of the inflammation. Nutritional support allows these deficiencies in calories, macro- and micro-nutrients to be rectified. Enteral nutrition is also a primary therapy for IBD, especially for Crohn’s disease, as it allows the inflammatory activity to be controlled, kept in remission, and prevents or delays the need for surgery. Nutritional support is especially important in childhood IBD as an alternative to pharmacological treatment. This report discusses the complex relationship between diet and IBD.

Partial replacement of dietary (n-6) fatty acids with medium-chain triglycerides decreases the incidence of spontaneous colitis in interleukin-10-deficient mice

Enteral nutrition has a primary therapeutic effect in active Crohn's disease. It is unknown which nutrient(s) account for this action, but a role for both the amount and type of dietary fat has been postulated. Some clinical and experimental data suggest that medium-chain triglycerides (MCT) may reduce intestinal inflammation. We aimed to assess the effect of replacing part of the dietary fat with MCT on the incidence and severity of colitis in interleukin (IL)-10(-/-) mice under specific pathogen-free conditions. Twenty-four IL-10(-/-) 4-wk-old mice were randomized to receive a control diet based on sunflower oil [(n-6) fatty acids (FA)] and an experimental isocaloric, isonitrogenous diet with 50% sunflower and 50% coconut oil (MCT diet). When the mice were 12 wk old, they were killed and the colon was examined for the presence of colitis, lymphocyte subpopulations and apoptosis, ex vivo cytokine production in supernatant of colon explants, toll-like receptor (TLR)-2 and TLR-9 mRNA, and FA profile in colonic tissue homogenates. Colitis incidence was lower in the IL-10(-/-) mice fed the MCT diet (1/12) than in the mice fed the control diet (8/12; P = 0.03). The histological damage score was also lower in the former (P < 0.0005). Feeding the MCT diet resulted in fewer total and apoptotic intraepithelial CD3+ and lamina propria CD3+CD4+ lymphocytes, as well as downregulated production of IL-6 and interferon-gamma, and reduced TLR-9 mRNA. We conclude that partial replacement of dietary (n-6) FA with MCT decreases the incidence of colitis in a model of spontaneous intestinal inflammation and provide experimental arguments for a possible primary therapeutic effect of MCT in human Crohn's disease.

Symposium on 'The challenge of translating nutrition research into public health nutrition'. Session 3: Joint Nutrition Society and Irish Nutrition and Dietetic Institute Symposium on 'Nutrition and autoimmune disease'. Nutrition in Crohn's disease

The exact aetiology of Crohn's disease remains unknown. The consensus is that the disease results from a complex interaction between genes, immunity and environmental factors. Diet is attractive, in theory, as an environmental risk factor in the aetiology of the disease. The epidemiological data, often impeded by methodological issues, have failed to confirm a direct link between pre-diet illness and the development of Crohn's disease. Once diagnosed, however, nutrition has an important role in disease management. Among the nutritional issues are malnutrition, weight loss and suboptimal nutritional status; these outcomes may be present at any stage of the disease but are likely to be overt during acute illness and hospitalisation. Malnutrition has been identified in approximately 40% of hospital admissions with Crohn's disease and is associated with higher mortality, longer hospital stays and higher healthcare costs. Patients in remission may indeed be overweight and appear to be influenced by the general population trends toward overweight and obesity. Irrespective of BMI, patients are at risk of micronutrient deficiencies. Vitamin D deficiency, for example, is common in Crohn's disease and has important implications for bone health. Moreover, newer evidence suggests that vitamin D has potential anti-inflammatory effects. Dietary approaches, in the form of enteral nutrition, have previously been shown to reduce inflammation and treat the active disease. Current guidelines now recommend that corticosteroids are more effective than enteral nutrition for treating adults. Enteral nutrition has important growth and developmental benefits and continues to be a recommended therapy for children with Crohn's disease.

Nutritional therapy for active Crohn’s disease

Nutritional therapy for active Crohn’s disease (CD) is an underutilized form of treatment in adult patients, though its use is common in the paediatric population. There is evidence that nutritional therapy can effectively induce remission of CD in adult patients. Enteral nutrition therapy is safe and generally well tolerated. Meta-analysis data suggest that corticosteroids are superior to nutritional treatment for induction of remission in active CD. However, the potential side effects of such pharmacotherapy must be taken into consideration. This review examines the evidence for the efficacy of elemental and polymeric diets, and the use of total parenteral nutrition in active CD.

Comparison of cytokine modulation by natural peroxisome proliferator-activated receptor gamma ligands with synthetic ligands in intestinal-like Caco-2 cells and human dendritic cells--potential for dietary modulation of peroxisome proliferator-activated receptor gamma in intestinal inflammation

BACKGROUND

Peroxisome proliferator-activated receptor gamma (PPARgamma) plays a role in the regulation of intestinal inflammation and is activated by both natural (polyunsaturated fatty acid; PUFAs) and synthetic (troglitazone) ligands. The fatty acid content of defined formula diets may play a role in mediating the antiinflammatory effect, but the mechanism is unclear.

OBJECTIVE

We evaluated to what extent the effect of PUFAs on intestinal inflammation is mediated via PPARgamma.

DESIGN

The human enterocyte-like cell line Caco-2 and human dendritic cells were stimulated by interleukin (IL) 1beta and lipoprotein polysaccharide, respectively, in the presence of PPARgamma agonists (troglitazone or PUFAs) or antagonist (GW9662). Five PUFAs were tested: alpha-linolenic acid (ALA), conjugated linoleic acid (CLA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and gamma-linolenic acid (GLA). Cytokine production was measured by enzyme-linked immunosorbent assay and PPARgamma, I-kappaB, and inducible nitric oxide synthase (iNOS) expression by Western blot.

RESULTS

In Caco-2 cells, IL-6 secretion was significantly decreased by troglitazone, DHA, EPA, and GLA. IL-8 production was significantly decreased by troglitazone, ALA, DHA, EPA, and GLA. PPARgamma expression was significantly increased by troglitazone, DHA, and EPA. iNOS expression was significantly decreased by troglitazone, DHA, and EPA. Troglitazone and PUFAs at 0.1 mumol/L tended to increase the expression of I-kappaB. Addition of GW9662 reversed the effect of troglitazone and PUFAs at 0.1 mumol/L on IL-8 production and decreased the expression of PPARgamma. EPA and DHA also modulated the dendritic cell response to lipoprotein polysaccharide.

CONCLUSIONS

The tested PUFAs exerted an antiinflammatory effect in vitro in both models. This effect of PUFAs in Caco-2 cells is similar to that of troglitazone on intestinal inflammation mediated by PPARgamma, and the potency of the antiinflammatory effect is linked to the number of double bonds.

Nutrition in inflammatory bowel disease

PURPOSE OF REVIEW

Nutrition plays a significant role in the pathogenesis and treatment of the two major forms of inflammatory bowel disease: Crohn's disease and ulcerative colitis. In addition, patients with inflammatory bowel disease are often found to have nutrient deficiencies at the time of diagnosis, whereas others develop features of malnutrition over the course of their illness. Therefore, an understanding of the relationship between nutrients and inflammatory bowel disease is important if these patients are to receive optimal care.

RECENT FINDINGS

Epidemiologic and basic research has helped to shed light on the interaction between diet and the pathogenesis of inflammatory bowel disease. Numerous clinical trials utilizing various types of lipids, including fish oil and short chain fatty acids, suggest that fats play an important role in the inflammatory response that characterizes inflammatory bowel disease. Vitamins and other micronutrients involved in nutrient metabolism and modulation of oxidative stress are also considered in this review.

SUMMARY

This update discusses nutritional issues that can be used to help prevent and treat nutrient deficiencies and ameliorate disease activity in individuals with inflammatory bowel disease.

Genes, diet and inflammatory bowel disease

Inflammatory bowel disease (IBD) arises in part from a genetic predisposition, through the inheritance of a number of contributory genetic polymorphisms. These variant forms of genes may be associated with an abnormal response to normal luminal bacteria. A consistent observation across most populations is that any of three polymorphisms of the Caspase-activated recruitment domain (CARD15) gene are more prevalent in IBD patients as compared with unaffected controls. Similar aberrant responses to bacteria are associated with variants in Autophagy-related 16-like 1 (ATG16L1) and human defensin (HBD-2, -3 and -4) genes. The defective bacterial signal in turn leads to an excessive immune response, presenting as chronic gut inflammation in susceptible individuals. Inconsistent population reports implicate the major histocompatability complex (MHC), that encodes a number of human leukocyte antigens (HLA), MHC class I chain-related gene A (MICA) or cytokines, such as tumour necrosis factor-alpha (TNF-alpha). Toll-like receptors encoded by the TLR4 or TLR9 genes may also play a role. Recent whole genome scans suggest that a rare variant in the interleukin-23 receptor (IL23R) gene may actually protect against IBD. Other implicated genes may affect mucosal cell polarity (Drosophila discs large homologue 5, DLG5) or mucosal transporter function (sodium dependent organic cation transporters, SLC22A4 and SLC22A5). A variant in ABCB1 (ATP-binding cassette subfamily B member 1) may be especially associated with increased risk of UC. While pharmacogenetics is increasingly being used to predict and optimise clinical response to therapy, nutrigenetics may have even greater potential. In many cases, IBD can be controlled through prescribing an elemental diet, which appears to act through modulating cytokine response and changing the gut microbiota. More generally, no single group of dietary items is beneficial or detrimental to all patients, and elimination diets have been used to individualise dietary requirements. However, recognising the nature of the genes involved may suggest a more strategic approach. Pro- or prebiotics will directly influence the microbial flora, while immunonutrition, including omega-3 fatty acids and certain polyphenols, may reduce the symptoms of gut inflammation. The expression of gut transporters may be modulated through various herbal remedies including green tea polyphenols. Such approaches would require that the gene of interest is functioning normally, other than its expression being up or down-regulated. However, new approaches are being developed to overcome the effects of polymorphisms that affect the function of a gene. A combination of human correlation studies with experimental models could provide a rational strategy for optimising nutrigenetic approaches to IBD.

Novel substrates

Enteral and parenteral feeds need at least to contain adequate amounts of water, energy, protein, electrolytes, vitamins and trace elements. Ready-manufactured parenteral feeds for example are incomplete because of shelf-life constraints and require the addition of vitamins (especially) and trace elements. Acute vitamin deficiencies, notably thiamine deficiency, can be precipitated if this is not adhered to. An increasing interest, however, exists in the use of feeds containing substrates, which are intended to improve patient outcome in particular clinical circumstances. The purpose of this article is to examine as to what is available and make recommendations on their use. It deals with artificial feeds only - disease-specific diets are outside our remit.

Lipid metabolism in active Crohn's disease: pre-results

BACKGROUND

Crohn's disease (CD) is a chronic relapsing disease. Especially acute period may be associated with metabolic disturbances. Alteration of lipid metabolism has been described in critically ill patients and hypocholesterolemia is associated with poor prognosis. The human organism acquires cholesterol by two principal processes - synthesis de novo, and absorption from the diet. It is possible to assess, using cholesterol synthesis markers (lathosterol) and cholesterol absorption markers (sitosterol, campesterol) the leading form of cholesterol acquisition.

AIM

The aim of this study is assess the association between the lipid profile in plasma and the plasma concentration of sterols in active CD patients and in control subjects.

METHOD

Routine laboratory tests, CDAI, lipid and non-cholesterol sterols plasma levels were performed on days 3, 14 and 28. The metabolic parameters have been compared with a control cohort of 100 healthy blood donors.

RESULTS

Presently, complete data for 8 patients are available The serum total cholesterol, LDL and HDL cholesterol, and triglyceride concentrations were lower in patients with acute Crohn's disease than in the control group. Moreover lathosterol, campesterol and sitosterol concentrations were lower, whereas squalene concentration was higher than in controls. As mentioned above, complete data are not currently available. Therefore statistical analysis has not been finished.

CONCLUSION

Our pre-results show substantial abnormalities in the concentrations of plasma lipids and non-cholesterol sterols, which are presented as markers of cholesterol requirement, in patients with acute CD.

Enteral nutritional therapy for induction of remission in Crohn's disease

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This meta-analysis aims to provide an update on the existing effectiveness data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the effectiveness of exclusive enteral nutrition (EN) as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on effectiveness.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2006) and EMBASE (1984-2006), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: American Journal of Gastroenterology, Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two authors and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstract publications, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 15 included eligible trials (one abstract) comparing different formulations of EN for the treatment of active CD, 11 compared one (or more) elemental formula to a non-elemental one, three compared enteral diets of similar protein composition but different fat composition, and one compared non-elemental diets differing only in glutamine enrichment. Meta-analysis of ten trials comprising 334 patients demonstrated no difference in the efficacy of elemental versus non-elemental formulas (OR 1.10; 95% CI 0.69 to 1.75). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no statistically significant differences. Further analysis of seven trials including 209 patients treated with EN formulas of differing fat content (low fat: < 20 g/1000 kCal versus high fat: > 20 g/1000 kCal) demonstrated no statistically significant difference in efficacy (OR 1.13; 95% CI 0.63 to 2.01). Similarly, the effect of very low fat content (< 3 g/1000 kCal) or type of fat (long chain triglycerides) were investigated, but did not demonstrate a difference in efficacy in the treatment of active CD, although a non significant trend was demonstrated favoring very low fat and very low long chain triglyceride content. This result should be interpreted with caution due to statistically significant heterogeneity and small sample size. Sensitivity analyses had no significant effects on the results. The role of specific fatty acids or disease characteristics on response to therapy could not be evaluated. In part B, eight trials (including two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of six trials that included 192 patients treated with enteral nutrition and 160 treated with steroids yielded a pooled OR of 0.33 favouring steroid therapy (95% CI 0.21 to 0.53). A sensitivity analysis including the abstracts resulted in an increase in the number of participants to 212 in the enteral nutrition group and 179 in the steroid group but the meta-analysis yielded a similar result (OR 0.36; 95% CI 0.23 to 0.56). There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

AUTHORS' CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in previous systematic reviews. Protein composition does not influence the effectiveness of EN in the treatment of active CD. A non significant trend favouring very low fat and/or very low long chain triglyceride content exists but larger trials are required to explore the significance of this finding.

Perinodal Adipose Tissue and Fatty Acid Composition of Lymphoid Tissues in Patients with and without Crohn's Disease and Their Implications for the Etiology and Treatment of CD

The physiological bases for roles of adipose tissue and fatty acids in the symptoms and dietary treatments of Crohn's disease are poorly understood. The hypothesis developed from experiments on rodents that perinodal adipocytes are specialized to provision adjacent lymphoid tissues was tested by comparing the composition of triacylglycerol fatty acids in homologous samples of mesenteric adipose tissue and lymph nodes from patients with or without Crohn's disease. Mesenteric perinodal and other adipose tissue, and lymph nodes, were collected during elective surgery for Crohn's disease and other conditions. Fatty acids were extracted, identified, and quantified by thin-layer and gas-liquid chromatography. Perinodal adipose tissue contained more unsaturated fatty acids than other adipose tissue in controls, as reported for other mammals, but site-specific differences were absent in Crohn's disease. Lipids from adipose and lymphoid tissues had more saturated fatty acids, but fewer polyunsaturates in Crohn's disease patients than controls. In adipose tissue samples, depletion of n-3 polyunsaturates was greatest, but n-6 polyunsaturates, particularly arachidonic acid, were preferentially reduced in lymphoid cells. Ratios of n-6/n-3 polyunsaturates were higher in adipose tissue but lower in lymphoid cells in Crohn's disease patients than in controls. Site-specific differences in fatty acid composition in normal human mesentery are consistent with local interactions between lymph node lymphoid cells and adjacent adipose tissue. But these site-specific properties are absent in Crohn's disease, causing anomalies in composition of lymphoid cell fatty acids, which may explain the efficacy of elemental diets containing oils rich in n-6 polyunsaturates.

Enteral feeding in inflammatory bowel disease

PURPOSE OF REVIEW

Treatment algorithms for inflammatory bowel disease are changing rapidly. Increased and earlier use of immunomodulatory drugs and availability of biologic agents have reduced dependence on corticosteroids and made mucosal healing a realistic goal. It is timely to debate the role of enteral nutrition in this evolving therapeutic armamentarium for Crohn's disease, and to examine the mechanisms of its anti-inflammatory effects in light of current understanding of disease pathogenesis.

RECENT FINDINGS

Clinical studies have suggested that response to enteral nutrition is associated with decreased mucosal inflammation in Crohn's disease, that isolated Crohn's colitis is less responsive and that exclusive enteral nutrition is required. Basic research has demonstrated that lipids in the intestinal lumen can alter signalling of the mucosal immune system by intestinal epithelial cells. Exclusive enteral nutrition is associated with alteration of enteric microflora.

SUMMARY

Enteral nutrition is an efficacious treatment of active inflammation involving the ileum; recent-onset disease may be particularly responsive. The significance of effects on enteric flora deserves further exploration in view of the importance of microbes to disease pathogenesis.

ESPEN Guidelines on Enteral Nutrition: Gastroenterology

Undernutrition as well as specific nutrient deficiencies have been described in patients with Crohn's disease (CD), ulcerative colitis (UC) and short bowel syndrome (SBS). The present guideline gives evidence-based recommendations for the indication, application and type of formula of enteral nutrition (EN) (oral nutritional supplements (ONS) or tube feeding (TF)) in these patients. It was developed in an interdisciplinary consensus-based process in accordance with officially accepted standards and is based on all relevant publications since 1985. ONS and/or TF in addition to normal food is indicated in undernourished patients with CD or CU to improve nutritional status. In active CD EN is the first line therapy in children and should be used as sole therapy in adults mainly when treatment with corticosteroids is not feasible. No significant differences have been shown in the effects of free amino acid, peptide-based and whole protein formulae for TF. In remission ONS is recommended only in steroid dependent patients in CD. In patients with SBS TF should be introduced in the adaptation phase and should be changed with progressing adaptation to ONS in addition to normal food.

To feed or not to feed? Are nutritional supplements worthwhile in active Crohn's disease?

Partial enteral nutrition is unlikely to suppress inflammation and so treat active Crohn's disease

Treatment of active Crohn's disease in children using partial enteral nutrition with liquid formula: a randomised controlled trial

BACKGROUND AND AIMS

Total enteral nutrition (TEN) with a liquid formula can suppress gut inflammation and induce remission in active Crohn's disease. The mechanism is obscure. Studies have suggested that long term nutritional supplementation with a liquid formula (partial enteral nutrition (PEN)) may also suppress inflammation and prevent relapse. The aim of this study was to compare PEN with conventional TEN in active Crohn's disease.

PATIENTS AND METHODS

Fifty children with a paediatric Crohn's disease activity index (PCDAI)>20 were randomly assigned to receive 50% (PEN) or 100% (TEN) of their energy requirement as elemental formula for six weeks. The PEN group was encouraged to eat an unrestricted diet while those receiving TEN were not allowed to eat. The primary outcome was achievement of remission (PCDAI<10). Secondary analyses of changes in erythrocyte sedimentation rate (ESR), C reactive protein, albumin, and platelets were performed to look for evidence of anti-inflammatory effects.

RESULTS

Remission rate with PEN was lower than with TEN (15% v 42%; p=0.035). Although PCDAI fell in both groups (p=0.001 for both), the reduction was greater with TEN (p=0.005). Moreover, the fall in PCDAI with PEN was due to symptomatic and nutritional benefits. With both treatments there were significant improvements in relation to abdominal pain, "sense of wellbeing", and nutritional status. However, only TEN led to a reduction in diarrhoea (p=0.02), an increase in haemoglobin and albumin, and a fall in platelets and ESR.

CONCLUSIONS

TEN suppresses inflammation in active Crohn's disease but PEN does not. This suggests that long term nutritional supplementation, although beneficial to some patients, is unlikely to suppress inflammation and so prevent disease relapse.

Nutrition in inflammatory bowel disease

Nutrition has an important role in the management of inflammatory bowel disease. This role includes the prevention and correction of malnutrition, the prevention of osteoporosis and in children the promotion of optimal growth and development. In active Crohn's disease nutritional therapy (in the form of enteral feeding) is an effective primary therapy for many patients. Corticosteroids, however, are more effective than enteral diet therapy in adults. Enteral diets should be considered as primary therapy in pediatric Crohn's disease, especially in children with poor nutritional status or growth impairment. Enteral nutrition does not have a proven primary therapeutic role in ulcerative colitis. There are many theories that suggest that diet may be implicated in the aetiology of inflammatory bowel disease, however, there are, as yet, no dietary approaches proven to reduce the risk of developing IBD.