Krill Oil and Its Bioactive Components as a Potential Therapy for Inflammatory Bowel Disease: Insights from In Vivo and In Vitro Studies

Krill oil is extracted from krill, a small crustacean in the Antarctic Ocean. It has received growing attention because of krill oil's unique properties and diverse health benefits. Recent experimental and clinical studies suggest that it has potential therapeutic benefits in preventing the development of a range of chronic conditions, including inflammatory bowel disease (IBD). Krill oil is enriched with long-chain n-3 polyunsaturated fatty acids, especially eicosapentaenoic and docosahexaenoic acids, and the potent antioxidant astaxanthin, contributing to its therapeutic properties. The possible underlying mechanisms of krill oil's health benefits include anti-inflammatory and antioxidant actions, maintaining intestinal barrier functions, and modulating gut microbiota. This review aims to provide an overview of the beneficial effects of krill oil and its bioactive components on intestinal inflammation and to discuss the findings on the molecular mechanisms associated with the role of krill oil in IBD prevention and treatment.

Dietary intake of yacon roots (Smallanthus sonchifolius) affects gut microbiota and fecal mucin and prevents intestinal inflammation in mice

Consumption of yacon (Smallanthus sonchifolius) is associated with beneficial effects such as prevention of metabolic diseases. Yacon root is known to contain various bioactive components including indigestible carbohydrates, but the alteration of intestinal environment after treatment with yacon has not been fully investigated. This study investigated yacon-containing diet effects on the intestinal environment in mice, including microbial composition, short-chain fatty acid levels, and mucus content. After mice were administered yacon-containing diet for 4 weeks, 16S rRNA gene sequencing analyses revealed their fecal microbiota profiles. Organic acid concentrations in cecal contents were measured using an HPLC system. Compared to the control group, yacon-containing diet-received mice had significantly higher the concentrations of succinic acid, lactic acid, acetic acid, and propionic acid. The fecal mucin content was also higher in yacon-containing diet-received mice. Results of 16S rRNA gene sequencing analyses showed that the relative abundances of 27 taxa differed significantly in yacon-containing diet-received mice. Furthermore, results show effects of yacon administration on intestinal inflammation using 2,4,6-trinitrobenzene sulfonic acid induced colitis model in mice. Increased colonic damage and myeloperoxidase activity after 2,4,6-trinitrobenzene sulfonic acid treatment were suppressed in yacon-containing diet-received mice. Results suggest that oral intake of yacon root modulates the intestinal environment, thereby inhibiting intestinal inflammation.

Omega-3 Polyunsaturated Fatty Acids and the Intestinal Epithelium-A Review

Epithelial cells (enterocytes) form part of the intestinal barrier, the largest human interface between the internal and external environments, and responsible for maintaining regulated intestinal absorption and immunological control. Under inflammatory conditions, the intestinal barrier and its component enterocytes become inflamed, leading to changes in barrier histology, permeability, and chemical mediator production. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) can influence the inflammatory state of a range of cell types, including endothelial cells, monocytes, and macrophages. This review aims to assess the current literature detailing the effects of ω-3 PUFAs on epithelial cells. Marine-derived ω-3 PUFAs, eicosapentaenoic acid and docosahexaenoic acid, as well as plant-derived alpha-linolenic acid, are incorporated into intestinal epithelial cell membranes, prevent changes to epithelial permeability, inhibit the production of pro-inflammatory cytokines and eicosanoids and induce the production of anti-inflammatory eicosanoids and docosanoids. Altered inflammatory markers have been attributed to changes in activity and/or expression of proteins involved in inflammatory signalling including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), peroxisome proliferator activated receptor (PPAR) α and γ, G-protein coupled receptor (GPR) 120 and cyclooxygenase (COX)-2. Effective doses for each ω-3 PUFA are difficult to determine due to inconsistencies in dose and time of exposure between different in vitro models and between in vivo and in vitro models. Further research is needed to determine the anti-inflammatory potential of less-studied ω-3 PUFAs, including docosapentaenoic acid and stearidonic acid.

Trans-unsaturated fatty acid activates NLRP3 inflammasome in macrophages and exacerbates intestinal inflammation in mice

Higher consumption of trans fatty acid (TFA) is a risk factor for several inflammatory diseases including inflammatory bowel disease (IBD). However, the detailed mechanisms by which TFA intake affects IBD pathology remain unclear. We demonstrate here that elaidate, a trans-isomer of oleate, enhances interleukin (IL)-1β production through the activation of NLRP3 inflammasome in mouse bone marrow-derived macrophages (BMDMs). Oleate has no effect on IL-1β production. Elaidate also induces oxidative stress and activates endoplasmic reticulum stress in BMDMs. The elaidate-induced IL-1β production is suppressed by co-treatments with antioxidants and a chemical chaperone. Furthermore, we analyze the effects of elaidate administration on intestinal inflammation using 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model in mice. Increased colonic damage and myeloperoxidase activity after TNBS treatment are elevated by elaidate administration. Also, TNBS treatment induces IL-1β production in colonic mucosa; elaidate administration enhances the induction. We believe that these data reveal some mechanisms by which the TFA intake is associated with increased risk for IBD.

Nutrition and the Immune System: A Complicated Tango

Enthusiasm exists for the potential of diet to impact the immune system, prevent disease and its therapeutic potential. Herein, we describe the challenge to nutrition scientists in defining this relationship through case studies of diets and nutrients in the context of allergic and autoimmune diseases. Moderate-quality evidence exists from both human intervention and observational studies to suggest that diet and individual nutrients can influence systemic markers of immune function and inflammation; numerous challenges exist for demonstrating the impact of defined diets and nutrient interventions on clearly influencing immune-mediated-clinical disease endpoints. A growing body of evidence suggests that further consideration of dietary patterns, immune system and gut microbiome composition and function, and subsequent epigenetic modifications are needed to improve our understanding of diet-immune system interactions.

Therapeutic effect of adenosine on experimentally induced acute ulcerative colitis model in rats

Purpose

To examine the therapeutic effect of external adenosine on an acetic acid-induced acute ulcerative colitis model in rats.

Methods

Thirty male mature rats were divided into three groups as control, acute colitis (AC) and AC+adenosine group (AC+AD). AC was induced by rectal administration of 4% acetic acid (AA). 5mg/kg/day adenosine was performed i.p for 4 weeks to AC+AD group. Rectum and colon were excised for microscopic and histopathological histopathologic evaluations, and immunohistochemical analysis of nuclear factor kappa B (NF-kB). Blood samples were collected for biochemical detection of TNF-α, Pentraxin-3 and malondialdehyde (MDA) levels.

Results

AC group had generalized hyperemia and hemorrhage with increased macroscopic and histopathological scores compared with control (P <0.0001) while adenosine treatment decreased these scores significantly (P <0.001), with reduced distribution of disrupted epithelium, leukocyte infiltrates, and focal hemorrhage. AC group showed significantly increased immunoexpression of NF-kB in rectum, plasma and tissue levels of TNF-α, plasma Pentraxin-3 and MDA levels (P <0.0001) while adenosine reduced these levels (P < 0.05).

Conclusion

Adenosine appears to promote healing of colon and rectum exposed to AA-induced AC, suggesting a boosting effect of adenosine on the intestinal immune system to cure ulcerative colitis.

European Crohn's and Colitis Organisation Topical Review on Complementary Medicine and Psychotherapy in Inflammatory Bowel Disease

Patients with inflammatory bowel disease [IBD] increasingly use alternative and complementary therapies, for which appropriate evidence is often lacking. It is estimated that up to half of all patients with IBD use various forms of complementary and alternative medicine during some point in their disease course. Considering the frequent use of such therapies, it is crucial that physicians and patients are informed about their efficacy and safety in order to provide guidance and evidence-based advice. Additionally, increasing evidence suggests that some psychotherapies and mind-body interventions may be beneficial in the management of IBD, but their best use remains a matter of research. Herein, we provide a comprehensive review of some of the most commonly used complementary, alternative and psychotherapy interventions in IBD.

Eicosapentaenoic Acid Reduces Fecal Levels of Calprotectin and Prevents Relapse in Patients With Ulcerative Colitis

BACKGROUND & AIMS

High fecal levels of calprotectin indicate mucosal inflammation and have been shown to predict relapse in patients with ulcerative colitis (UC). Eicosapentaenoic acid (EPA), the major component of n-3 fish oil, has anti-inflammatory properties in patients with chronic inflammatory disorders. We performed a placebo-controlled trial of patients with UC at risk of relapse to determine the ability of the free fatty acid form of EPA (EPA-FFA) to reduce intestinal inflammation, using fecal level of calprotectin as a marker.

METHODS

From June 2014 to May 2016, 60 patients with UC with a partial Mayo score < 2 and fecal calprotectin ≥150 μg/g, in stable therapy for at least the 3 previous months, were randomly assigned to groups (1:1) given either EPA-FFA (500 mg, twice daily) or placebo for 6 months. A colonoscopy was performed at baseline. Clinical assessments and measurements of fecal calprotectin were made at baseline, at study months 3 and 6, or the time of clinical relapse. Patients with a relapse of UC underwent a second colonoscopy. The primary end point was a 100-point reduction in fecal levels of calprotectin at 6 months from the baseline value; the secondary end point was maintenance of clinical remission at 6 months.

RESULTS

The primary end point was achieved by 19 of 30 patients (63.3%) in the EPA-FFA group vs 4 of 30 patients (13.3%) in the placebo group (odds ratio, 12.0; 95% CI, 3.12-46.24; P < .001). The secondary end point was achieved by 23 of 30 patients (76.7%) in the EPA-FFA group vs 15 of 30 (50%) patients in the placebo group (OR, 3.29; 95% CI, 1.08-9.95; P = .035). No serious adverse events were observed.

CONCLUSIONS

In a placebo-controlled trial of 60 patients with UC, we found 6 months' administration of EPA-FFA to reduce fecal levels of calprotectin with no serious adverse events. This agent might be used to induce and maintain symptom-free remission in patients with UC. ClinicalTrials.gov number: NCT02179372.

Treatment with Mesna and n-3 polyunsaturated fatty acids ameliorates experimental ulcerative colitis in rats

Oxidative damage is a central feature of ulcerative colitis. Here, we tested whether the antioxidant Mesna, when administered alone or in combination with n-3 polyunsaturated fatty acids (n-3 PUFAs), affects the outcome of dextran sodium sulphate (DSS)-induced ulcerative colitis in rats. After the induction of colitis, DSS-treated rats were further treated orally (p.o), intraperitoneally (i.p) or intrarectally (i.r) for either 7 or 14 days with Mesna, n-3 PUFAs or both. Rats were euthanized at the end of each treatment period. Clinical disease activity index was recorded throughout the experiment. At necropsy colorectal gross lesions were scored. Colitis was scored histologically, and the expression of myeloperoxidase (MPO), caspase-3, inducible nitric oxide synthase (iNOS) and nuclear factor κB (NF-κΒ) in colonic tissue was assessed by immunohistochemistry. Mesna alone was sufficient to significantly reduce colorectal tissue damage when administered orally or intraperitoneally. Orally coadministered n-3 PUFAs enhanced this effect, resulting in the significant suppression of DSS colitis after 7 days, and a remarkable recovery of colorectal mucosa was evident after 14 days of treatment. The amelioration of colon pathology co-existed with a significant decrease in MPO expression, overexpression of iNOS and reduction of nuclear NF-κB p65 in inflammatory cells, and the suppression of apoptosis in colonic epithelial cells. The simultaneous administration of Mesna and n-3 PUFAs is particularly effective in ameliorating DSS colitis in rats, by reducing oxidative stress, inflammation and apoptosis, probably through a mechanism that involves the inhibition of NF-κB and overexpression of iNOS.

Metabolic phenotyping of an adoptive transfer mouse model of experimental colitis and impact of dietary fish oil intake

Inflammatory bowel diseases are acute and chronic disabling inflammatory disorders with multiple complex etiologies that are not well-defined. Chronic intestinal inflammation has been linked to an energy-deficient state of gut epithelium with alterations in oxidative metabolism. Plasma-, urine-, stool-, and liver-specific metabonomic analyses are reported in a naïve T cell adoptive transfer (AT) experimental model of colitis, which evaluated the impact of long-chain n-3 polyunsaturated fatty acid (PUFA)-enriched diet. Metabolic profiles of AT animals and their controls under chow diet or fish oil supplementation were compared to describe the (i) consequences of inflammatory processes and (ii) the differential impact of n-3 fatty acids. Inflammation was associated with higher glycoprotein levels (related to acute-phase response) and remodeling of PUFAs. Low triglyceride levels and enhanced PUFA levels in the liver suggest activation of lipolytic pathways that could lead to the observed increase of phospholipids in the liver (including plasmalogens and sphingomyelins). In parallel, the increase in stool excretion of most amino acids may indicate a protein-losing enteropathy. Fecal content of glutamine was lower in AT mice, a feature exacerbated under fish oil intervention that may reflect a functional relationship between intestinal inflammatory status and glutamine metabolism. The decrease in Krebs cycle intermediates in urine (succinate, α-ketoglutarate) also suggests a reduction in the glutaminolytic pathway at a systemic level. Our data indicate that inflammatory status is related to this overall loss of energy homeostasis.

Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease

BACKGROUND

The anti-inflammatory effects of n-3 (omega-3 fatty acids, fish oil) have been suggested to be beneficial in chronic inflammatory disorders such as inflammatory bowel disease. This review is an update of a previously published Cochrane review.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintenance of remission in Crohn's disease (CD).

SEARCH METHODS

The following databases were searched from inception to November 2013 without language restriction: CENTRAL, MEDLINE, EMBASE, HealthSTAR, PubMed, and ACP journal club.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of n-3 for maintenance of remission in CD were included. Studies must have enrolled patients of any age group, who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil or n-3 given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups.

DATA COLLECTION AND ANALYSIS

The primary outcome was the relapse rate and secondary outcomes included change in disease activity scores, time to first relapse and adverse events. Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using the Cochrane risk of bias tool. The overall quality of the evidence supporting the primary and selected secondary outcomes was reassessed for the current update using the GRADE system. We used the RevMan software for analyses. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for dichotomous outcomes and the hazard ratio and 95% CI for time-to-event outcomes. Random-effects or fixed-effect models were used according to degree of heterogeneity and sensitivity analyses were performed in an attempt to explore possible sources of heterogeneity.

MAIN RESULTS

Six studies with a total of 1039 patients were eligible for inclusion. The two largest studies were rated as low risk of bias for all assessed items. Four studies were rated as unclear risk of bias for randomization and allocation concealment. Two studies were rated as high risk of bias for incomplete outcome data and selective reporting. There was a marginal significant benefit of n-3 therapy for maintenance of remission. Thirty-nine per cent of patients in the n-3 group relapsed at 12 months compared to 47% of placebo patients (6 studies, 1039 patients; RR 0.77, 95% CI 0.61 to 0.98). A GRADE analysis rated the overall quality of the evidence for the primary outcome (i.e. relapse) as very low due to unexplained heterogeneity (I2 = 58%), publication bias, and a high or unknown risk of bias in four studies in the pooled analysis. When two large studies at low risk of bias were considered the benefit was no longer statistically significant. Thirty-seven per cent of patients in the n-3 group relapsed at 12 months compared to 42% of placebo patients (2 studies, 738 patients; RR 0.88, 95% CI 0.74 to 1.05). No significant heterogeneity was identified for this pooled analysis ( I2 = 0%). A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was moderate due to sparse data (294 events). No serious adverse events were recorded in any of the studies but in a pooled analyses there was a significantly higher rate of diarrhea (4 studies, 862 patients; RR 1.36 95% CI 1.01 to 1.84) and upper gastrointestinal tract symptoms (5 studies, 999 patients; RR 1.65, 95% CI 1.25 to 2.18) in the n-3 treatment group.

AUTHORS' CONCLUSIONS

Evidence from two large high quality studies suggests that omega 3 fatty acids are probably ineffective for maintenance of remission in CD. Omega 3 fatty acids appear to be safe although they may cause diarrhea and upper gastrointestinal tract symptoms.

The Effect of n-3 Fatty Acids on Glucose Homeostasis and Insulin Sensitivity

Type 2 diabetes (T2D) as well as cardiovascular disease (CVD) represent major complications of obesity and associated metabolic disorders (metabolic syndrome). This review focuses on the effects of long-chain n-3 polyunsaturated fatty acids (omega-3) on insulin sensitivity and glucose homeostasis, which are improved by omega-3 in many animal models of metabolic syndrome, but remain frequently unaffected in humans. Here we focus on: (i) mechanistic aspects of omega-3 action, reflecting also our experiments in dietary obese mice; and (ii) recent studies analysing omega-3’s effects in various categories of human subjects. Most animal experiments document beneficial effects of omega-3 on insulin sensitivity and glucose metabolism even under conditions of established obesity and insulin resistance. Besides positive results obtained in both cross-sectional and prospective cohort studies on healthy human populations, also some intervention studies in prediabetic subjects document amelioration of impaired glucose homeostasis by omega-3. However, the use of omega-3 to reduce a risk of new-onset diabetes in prediabetic subjects still remains to be further characterized. The results of a majority of clinical trials performed in T2D patients suggest that omega-3 have none or marginal effects on metabolic control, while effectively reducing hypertriglyceridemia in these patients. Despite most of the recent randomized clinical trials do not support the role of omega-3 in secondary prevention of CVD, this issue remains still controversial. Combined interventions using omega-3 and antidiabetic or hypolipidemic drugs should be further explored and considered for treatment of patients with T2D and other diseases.

Trans fatty acids exacerbate dextran sodium sulphate-induced colitis by promoting the up-regulation of macrophage-derived proinflammatory cytokines involved in T helper 17 cell polarization

Numerous reports have shown that a diet containing large amounts of trans fatty acids (TFAs) is a major risk factor for metabolic disorders. Although recent studies have shown that TFAs promote intestinal inflammation, the underlying mechanisms are unknown. In this study, we examined the effects of dietary fat containing TFAs on dextran sodium sulphate (DSS)-induced colitis. C57 BL/6 mice were fed a diet containing 1·3% TFAs (mainly C16:1, C18:1, C18:2, C20:1, C20:2 and C22:1), and then colitis was induced with 1·5% DSS. Colonic damage was assessed, and the mRNA levels of proinflammatory cytokines and major regulators of T cell differentiation were measured. The TFA diet reduced survival and exacerbated histological damage in mice administered DSS compared with those fed a TFA-free diet. The TFA diet significantly elevated interleukin (IL)-6, IL-12p40, IL-23p19 and retinoic acid-related orphan receptor (ROR)γt mRNA levels in the colons of DSS-treated animals. Moreover, IL-17A mRNA levels were elevated significantly by the TFA diet, with or without DSS treatment. We also examined the expression of proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and peritoneal macrophages. These cells were exposed to TFAs (linoelaidic acid or elaidic acid) with or without LPS and the mRNA levels of various cytokines were measured. IL-23p19 mRNA levels were increased significantly by TFAs in the absence of LPS. Cytokine expression was also higher in LPS-stimulated cells exposed to TFAs than in unexposed LPS-stimulated cells. Collectively, our results suggest that TFAs exacerbate colonic inflammation by promoting Th17 polarization and by up-regulating the expression of proinflammatory cytokines in the inflamed colonic mucosa.

Effect of dietary fat on intestinal inflammatory diseases

Dietary fat has multiple roles on human health, and some dietary fat is used to treat organic diseases because of its anti-inflammatory effect. It is commonly accepted that omega-3 polyunsaturated fatty acid (PUFA) is beneficial on ischemic heart disease or rheumatic arthritis. On the contrary, effect of omega-3-PUFA on Crohn's disease remained controversial. That effect of omega-3 PUFA differs according to the location of inflamed intestine was hypothesized. To elucidate this hypothesis, to investigate the role of dietary fat on disease activity in different kind of murine models of intestinal inflammatory diseases was planned. The effect of omega-3 PUFA on small intestinal Crohn's disease model and large intestinal Crohn's disease model of mice. Chronic colitis model C57BL/6 mice received two cycles of dextran sodium sulfate solution treatment to induce chronic colitis. Feeding of omega-3 fat-rich diets exacerbated colitis with decrease in adiponectin expression. Chronic small intestinal inflammation model: SAMP1/Yit mice showed remarkable inflammation of the terminal ileum spontaneously. Feeding of omega-3 fat-rich diets for 16 weeks significantly ameliorated the inflammation of the terminal ileum. Enhanced infiltration of leukocytes and expression of mucosal addressin cell adhesion molecule-1 in intestinal mucosa was significantly decreased by omega-3 fat-rich diets treatment. Omega-3 PUFA has dual role, pro-/anti-inflammatory, on intestinal inflammatory diseases. The role of omega-3 fat and the potential for immunonutrition in inflammatory conditions of the gastrointestinal tract will be discussed.

Systematic review: the efficacy of herbal therapy in inflammatory bowel disease

BACKGROUND

Complementary and alternative medicine (CAM), particularly herbal therapy, is widely used by patients with inflammatory bowel disease (IBD) but controlled data are limited.

AIM

To systematically review the literature on the efficacy of herbal therapy in the treatment of ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

Publications in English and non-English literatures (MEDLINE, EMBASE, EBM Reviews, AMED, Global Health) were searched from 1947 to 2013 for controlled clinical studies of herbal therapy in IBD. Outcome measures included response and remission rates.

RESULTS

Twenty-one randomised controlled trials (14 UC; 7 CD) including a total of 1484 subjects (mean age 41, 50% female) were analysed. In UC, aloe vera gel, Triticum aestivum (wheat grass juice), Andrographis paniculata extract (HMPL-004) and topical Xilei-san were superior to placebo in inducing remission or response, and curcumin was superior to placebo in maintaining remission; Boswellia serrata gum resin and Plantago ovata seeds were as effective as mesalazine, whereas Oenothera biennis (evening primrose oil) had similar relapse rates as omega-3 fatty acids in the treatment of UC. In CD, Artemisia absinthium (wormwood) and Tripterygium wilfordii were superior to placebo in inducing remission, and preventing clinical recurrence of post-operative CD respectively.

CONCLUSIONS

Randomised controlled trials of herbal therapy for the treatment of IBD show encouraging results but studies remain limited and heterogenous. Larger controlled studies with stricter endpoints and better-defined patient groups are required to obtain more conclusive results on the use of CAM therapies in IBD.

Comparative protective effect of hawthorn berry hydroalcoholic extract, atorvastatin, and mesalamine on experimentally induced colitis in rats

The protective effect of hydroalcoholic extract of hawthorn berries (HBE) on acetic acid (AA)-induced colitis in rats was investigated. Forty-two Wistar rats were divided into seven groups, including control and test groups (n=6). The control animals received saline, and the test animals were treated with saline (sham group), mesalamine (50 mg/kg; M group), atorvastatin (20 mg/kg; A group), HBE (100 mg/kg; H group), mesalamine and HBE (HM group), or atorvastatin plus HBE (HA group), 3 days before and a week after colitis induction. Colitis was induced by administration of 1 mL AA (4%) via a polyethylene catheter intrarectally. High-performance liquid chromatography analyses showed that HBE contained 0.13% and 0.5% oleanolic acid and ursolic acid, respectively. Elevated myeloperoxidase activity and lipid peroxidation were attenuated in the HA group. The H and HM groups showed marked reductions in colitis-induced decreases in total thiol molecules and body weight. The histopathological studies revealed that HBE decreased colitis-induced edema and infiltration of neutrophils. Our data suggest the anti-inflammatory and antioxidant effects of HBE and atorvastatin protect against AA-induced colitis. The anti-inflammatory effect of HBE may be attributable to its ability to decrease myeloperoxidase activity as a biomarker of neutrophil infiltration.

Effects of increase in fish oil intake on intestinal eicosanoids and inflammation in a mouse model of colitis

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic intestinal inflammatory diseases affecting about 1% of western populations. New eating behaviors might contribute to the global emergence of IBD. Although the immunoregulatory effects of omega-3 fatty acids have been well characterized in vitro, their role in IBD is controversial.

METHODS

The aim of this study was to assess the impact of increased fish oil intake on colonic gene expression, eicosanoid metabolism and development of colitis in a mouse model of IBD. Rag-2 deficient mice were fed fish oil (FO) enriched in omega-3 fatty acids i.e. EPA and DHA or control diet for 4 weeks before colitis induction by adoptive transfer of naïve T cells and maintained in the same diet for 4 additional weeks. Onset of colitis was monitored by colonoscopy and further confirmed by immunological examinations. Whole genome expression profiling was made and eicosanoids were measured by HPLC-MS/MS in colonic samples.

RESULTS

A significant reduction of colonic proinflammatory eicosanoids in FO fed mice compared to control was observed. However, neither alteration of colonic gene expression signature nor reduction in IBD scores was observed under FO diet.

CONCLUSION

Thus, increased intake of dietary FO did not prevent experimental colitis.

Fish oil administration in older adults: is there potential for adverse events? A systematic review of the literature

Background

Omega-3 (n-3) fatty acid supplementation is becoming increasingly popular. However given its antithrombotic properties the potential for severe adverse events (SAE) such as bleeding has safety implications, particularly in an older adult population. A systematic review of randomized control trials (RCT) was conducted to explore the potential for SAE and non-severe adverse events (non-SAE) associated with n-3 supplementation in older adults.

Methods

A comprehensive search strategy using Medline and a variety of other electronic sources was conducted. Studies investigating the oral administration of n-3 fish oil containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or both against a placebo were sourced. The primary outcome of interest included reported SAE associated with n-3 supplementation. Chi-square analyses were conducted on the pooled aggregate of AEs.

Results

Of the 398 citations initially retrieved, a total of 10 studies involving 994 older adults aged ≥60 years were included in the review. Daily fish oil doses ranged from 0.03 g to 1.86 g EPA and/or DHA with study durations ranging from 6 to 52 weeks. No SAE were reported and there were no significant differences in the total AE rate between groups (n-3 intervention group: 53/540; 9.8%; placebo group: 28/454; 6.2%; p = 0.07). Non-SAE relating to gastrointestinal (GI) disturbances were the most commonly reported however there was no significant increase in the proportion of GI disturbances reported in participants randomized to the n-3 intervention (n-3 intervention group: 42/540 (7.8%); placebo group: 24/454 (5.3%); p = 0.18).

Conclusions

The potential for AEs appear mild-moderate at worst and are unlikely to be of clinical significance. The use of n-3 fatty acids and the potential for SAE should however be further researched to investigate whether this evidence is consistent at higher doses and in other populations. These results also highlight that well-documented data outlining the potential for SAE following n-3 supplementation are limited nor adequately reported to draw definitive conclusions concerning the safety associated with n-3 supplementation. A more rigorous and systematic approach for monitoring and recording AE data in clinical settings that involve n-3 supplementation is required.

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.

Dietary supplementation of krill oil attenuates inflammation and oxidative stress in experimental ulcerative colitis in rats

OBJECTIVE

To evaluate the effects of krill oil (KO) on inflammation and redox status in dextran sulfate sodium (DSS)-induced colitis in rats.

MATERIALS AND METHODS

Thirty male Wistar rats were divided into three groups: Control, DSS, and DSS + KO 5% in a 4-week diet study. Colitis was induced by 5% DSS in the drinking water the last week of the experiment. Weight and disease activity index (DAI), colon length, histological combined score (HCS), colon levels of selected cytokines and prostaglandins, markers of protein oxidative damage, fatty acid profile, and expression of selected genes were measured.

RESULTS

Rats in the DSS group increased their DAI and HCS compared with healthy controls. The colon length was significantly preserved after KO diet. Tumor necrosis factor (TNF)-α and interleukin (IL)-1β were elevated in the DSS group compared with controls. Cytokines and HCS were nonsignificantly lower in the KO versus the DSS group. Prostaglandin (PG)E(3) increased significantly in the KO versus the other groups. Peroxisome proliferator-activated receptor (PPAR)-γ expression was nonsignificantly increased while PPAR-γ coactivator 1α (Pparg1α) expression increased significantly after KO. The levels of protein oxidation markers decreased significantly.

CONCLUSIONS

KO showed protective potential against DSS colitis based on the preservation of colon length, reduction of oxidative markers and the consistent beneficial changes of HCS, cytokine, and (PG)E(3) levels, as well as PPAR-γ and Pparg1α expression compared with DSS alone. These findings indicate an anti-inflammatory and a protein antioxidant effect of KO.

Treatment of inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which includes Crohn's disease (CD) and ulcerative colitis (UC). These diseases have become important health problems. Medical therapy for IBD has advanced dramatically in the last decade with the introduction of targeted biologic therapies, the optimization of older therapies, including rugs such as immunomodulators and 5-aminosalicylic acid (5-ASA), and a better understanding of the mucosal immune system and the genetics involved in the pathogenesis of IBD. The goal of IBD therapy is to induce and maintain remission. The current treatment paradigm involves a step-up approach, moving to aggressive, powerful therapies only when milder therapies with fewer potential side effects fail or when patients declare themselves to have an aggressive disease. This review focuses on the current treatments for inflammatory bowel disease.

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.

Maintenance of remission in inflammatory bowel disease using omega-3 fatty acids (fish oil): a systematic review and meta-analyses

The objective was to systematically review the efficacy and safety of n-3 (omega-3 fatty acids, fish oil) for maintaining remission in Crohn's disease (CD) and ulcerative colitis (UC). Electronic databases were searched systematically for randomized controlled trials of n-3 for maintenance of remission in inflammatory bowel disease (IBD). Studies of patients of any age group who were in remission at the time of recruitment and were followed for at least 6 months were included. The primary outcome was relapse rate at the end of the follow-up period. Nine studies were eligible for inclusion; six studies of CD (n = 1039) and three of UC (n = 138). There was a statistically significant benefit for n-3 in CD (relative risk [RR] 0.77; 95% confidence interval [CI] 0.61-0.98); however, the studies were heterogeneous (I(2) = 58%). The absolute risk reduction was -0.14 (95% CI: -0.25 to -0.02). Opinions may vary on whether this is a clinically significant effect. Two well-done studies with a larger sample size reported no benefit. A sensitivity analysis excluding a small pediatric study resulted in the pooled RR being no longer statistically significant. A funnel plot analysis suggested publication bias for the smaller studies. For UC, there was no difference in the relapse rate between the n-3 and control groups (RR 1.02; 95% CI: 0.51-2.03). The pooled analysis showed a higher rate of diarrhea (RR 1.36; 95% CI: 1.01-1.84) and symptoms of the upper gastrointestinal tract (RR 1.96; 95% CI: 1.37-2.80) in the n-3 treatment group. There are insufficient data to recommend the use of omega 3 fatty acids for maintenance of remission in CD and UC.

Genes involved in the metabolism of poly-unsaturated fatty-acids (PUFA) and risk for Crohn's disease in children & young adults

Background and Objectives

Epidemiological evidence for the role of polyunsaturated fatty-acids (PUFA) in Crohn's disease (CD) is unclear, although the key metabolite leucotriene B4 (LTB₄) is closely linked to the inflammatory process. We hypothesized that inherited variation in key PUFA metabolic enzymes may modify susceptibility for CD.

Methods and Principal Results

A case-control design was implemented at three pediatric gastroenterology clinics in Canada. Children ≤20 yrs diagnosed with CD and controls were recruited. 19 single nucleotide polymorphisms (SNPs) across the ALOX5 (4) CYP4F3 (5) and CYP4F2 (10) genes, were genotyped. Associations between SNPs/haplotypes and CD were examined. A total of 431 cases and 507 controls were studied. The mean (±SD) age of the cases was 12.4 (±3.3) years. Most cases were male (56.4%), had ileo-colonic disease (L3±L4, 52.7%) and inflammatory behavior (B1±p, 87%) at diagnosis. One genotyped CYP4F3 SNP (rs2683037) not in Hardy-Weinberg Equilibrium was excluded. No associations with the remaining 4 CYP4F3 SNPs with CD were evident. However haplotype analysis revealed associations with a two-marker haplotype (TG) (rs3794987 & rs1290617) (p = 0.02; permuted p = 0.08). CYP4F2 SNPs, rs3093158 (OR (recessive) = 0.56, 95% CI = 0.35–0.89; p = 0.01), rs2074902 (OR (trend) = 1.26, 95% CI = 1.00–1.60; p = 0.05), and rs2108622 (OR (recessive) = 1.6, 95% CI = 1.00–2.57; p = 0.05) were significantly associated whereas rs1272 (OR (recessive) = 0.58, 95% CI = 0.30–1.13; p = 0.10) showed suggestions for associations with CD. A haplotype comprising these 4 SNPs was significantly associated (p = 0.007, permuted p = 0.02) with CD. Associations with SNP rs3780901 in the ALOX5 gene were borderline non-significant (OR (dominant) = 1.29, 95% CI = 0.99–1.67; p = 0.056). A haplotype comprising the 4 ALOX5 SNPs (TCAA, p = 0.036) was associated with CD, but did not withstand corrections for multiple comparisons (permuted p = 0.14).

Conclusions

Inherited variation in enzymes involved in the synthesis/metabolism of LTB₄ may be associated with CD. These findings implicate PUFA metabolism as a important pathway in the CD pathogenesis.

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.

Salmon diet in patients with active ulcerative colitis reduced the simple clinical colitis activity index and increased the anti-inflammatory fatty acid index--a pilot study

OBJECTIVE

Data concerning the anti-inflammatory effect of dietary n-3 polyunsaturated fatty acids (PUFAs) in patients with ulcerative colitis (UC) are inconsistent. Salmon fillet contains n-3 PUFAs and bioactive peptides that may improve its effects compared to fish oil alone. We assessed the efficacy of a salmon-rich diet in patients with mild ulcerative colitis.

METHODS

An 8-week intervention pilot study was designed to assess the effects of 600 grams Atlantic salmon consumption weekly in 12 UC patients. Simple clinical colitis activity index (SCCAI), a dietary questionnaire, sigmoidoscopy, selected serum inflammatory markers, fecal calprotectin, and plasma and rectal biopsy fatty acid profiles were assessed before and after intervention.

RESULTS

The levels of C20:4n-6 arachidonic acid in biopsies after dietary intervention were correlated with histology and endoscopy scores. The concentrations of n-3 PUFAs, C20:5n-3 eicosapentaenoic acid, C22:6n-3 docosahexaenoic acid, and the n-3/n-6 ratio increased in plasma and rectal biopsies. The anti-inflammatory fatty acid index (AIFAI) increased both in biopsies and plasma accompanied with a significantly reduced SCCAI.

CONCLUSION

Based on evidence of SCCAI and AIFAI and a tendency of decreased levels of CRP and homocysteine, intake of Atlantic salmon may have beneficial effects on disease activity in patients with mild ulcerative colitis.

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.

An α-linolenic acid-rich formula reduces oxidative stress and inflammation by regulating NF-κB in rats with TNBS-induced colitis

We have previously shown that α-linolenic acid (ALA), a (n-3) PUFA exerts in vitro antiinflammatory effects in the intestine. In this study, we aimed to evaluate its effect on inflammatory and oxidative stress in a colitis model. Colitis was induced in 2 groups at d 0 by intrarectal injection of 2-4-6-trinitrobenzen sulfonic acid (TNBS), whereas the control group received the vehicle. Rats we fed 450 mg . kg(-1) . d(-1) of ALA (TNBS+ALA) while the other colitic group (TNBS) and the control group were fed an isocaloric corn oil formula for 14 d (from d -7 to d 7). RBC fatty acid composition was assessed. Oxidative stress was studied by measuring urinary 8-isoprostanes (8-IP) and colon glutathione (GSH) concentration and inducible nitric oxide synthase (iNOS) expression. Colitis was assessed histologically, by production of proinflammatory mediators, including cytokines, leukotrienes B(4) (LTB(4)), and cyclooxygenase-2 (COX-2) and by nuclear factor-κB (NF-κB) activation. The ALA-rich diet significantly increased the RBC levels of ALA, eicosapentaenoic acid, and docosapentaenoic acid (n-3) compared with the TNBS group (P < 0.01 for all). The beneficial effect of ALA supplementation on oxidative stress was reflected by lower urinary 8-IP levels (P < 0.05), a normalized colon GSH concentration (P < 0.01), and reduced colon iNOS expression (P < 0.05) compared with the TNBS group. ALA also protected against colon inflammation as assessed by lower tumor necrosis factor-α secretion and mRNA level (P < 0.05), reduced NF-κB activation (P = 0.01), and lower colon lipid mediator concentrations such as LTB(4) and COX-2 (P < 0.05) compared with the TNBS group. These findings show that an ALA-rich formula is beneficial to TNBS-induced colitic rats via inhibition of oxidative and inflammatory stress.

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.

Dietary conjugated linoleic acid and n-3 polyunsaturated fatty acids in inflammatory bowel disease

PURPOSE OF REVIEW

Inflammatory bowel disease (IBD) is a debilitating and widespread immune-mediated illness of unknown etiology. Current treatments are modestly successful and with significant side-effects. The purpose of this review is to summarize the current understanding of mechanisms of action underlying the anti-inflammatory actions of conjugated linoleic acid (CLA) and n-3 polyunsaturated fatty acids (PUFAs) in IBD.

RECENT FINDINGS

Nutrition-based interventions that target peroxisome proliferator-activated receptors (PPARs) such as dietary CLA and n-3 PUFA have demonstrated anti-inflammatory efficacy in animal models of IBD. Clinical data on n-3 PUFA in IBD remains generally unimpressive, although results of a recent human study demonstrate that IBD remission can be maintained by maintaining the n-3: n-6 ratio more than 0.65 via n-3 PUFA intervention. In mice, CLA prevented inflammation-driven colorectal cancer by activating PPAR gamma and modulating regulatory T cells and macrophages. CLA is the subject of an ongoing clinical study in Crohn's disease patients.

SUMMARY

Compelling evidence demonstrates that n-3 PUFA and CLA prevent or ameliorate IBD in animal models. However, this basic knowledge has not been translated into novel nutrition-based clinical interventions. For both compounds there is an urgent need for placebo-controlled, large-scale, multicenter clinical trials.

Omega-3 polyunsaturated fatty acids ameliorate the severity of ileitis in the senescence accelerated mice (SAM)P1/Yit mice model

Clinical studies using omega-3 polyunsaturated fatty acids (omega3-PUFA) to Crohn's disease (CD) are conflicting. Beneficial effects of dietary omega3-PUFA intake in various experimental inflammatory bowel disease (IBD) models have been reported. However, animal models of large intestinal inflammation have been used in all previous studies, and the effect of omega3 fat in an animal model of small intestinal inflammation has not been reported. We hypothesized that the effects of omega3 fat are different between large and small intestine. The aim of this study was to determine whether the direct effect of omega3 fat is beneficial for small intestinal inflammation. Senescence accelerated mice (SAM)P1/Yit mice showed remarkable inflammation of the terminal ileum spontaneously. The numbers of F4/80-positive monocyte-macrophage cells as well as beta7-integrin-positive lymphocytes in the intestinal mucosa were increased significantly compared with those in the control mice (AKR-J mice). The area of mucosal addressin cell adhesion molecule-1 (MAdCAM-1)-positive vessels was also increased. The degree of expression levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6 and interferon (IFN)-gamma mRNA were increased significantly compared with those in the control mice. The feeding of two different kinds of omega3 fat (fish-oil-rich and perilla-oil-rich diets) for 16 weeks to SAMP1/Yit mice ameliorated inflammation of the terminal ileum significantly. In both the omega3-fat-rich diet groups, enhanced infiltration of F4/80-positive monocytes/macrophages in intestinal mucosa of SAMP1/Yit mice cells and the increased levels of MCP-1, IL-6 and IFN-gamma mRNA expression were ameliorated significantly compared with those in the control diet group. The results suggest that omega3 fat is beneficial for small intestinal inflammation by inhibition of monocyte recruitment to inflamed intestinal mucosa.

Therapeutic potential of n-3 polyunsaturated fatty acids in disease

PURPOSE

The potential therapeutic benefits of supplementation with n-3 polyunsaturated fatty acids (PUFAs) in various diseases are reviewed, and the antiinflammatory actions, activity, and potential drug interactions and adverse effects of n-3 PUFAs are discussed.

SUMMARY

Fish oils are an excellent source of long-chain n-3 PUFAs, such as eicosapentaenoic acid and docosahexaenoic acid. After consumption, n-3 PUFAs can be incorporated into cell membranes and reduce the amount of arachidonic acid available for the synthesis of proinflammatory eicosanoids (e.g., prostaglandins, leukotrienes). Likewise, n-3 PUFAs can also reduce the production of inflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1, and interleukin-6. Considerable research has been conducted to evaluate the potential therapeutic effects of fish oils in numerous conditions, including arthritis, coronary artery disease, inflammatory bowel disease, asthma, and sepsis, all of which have inflammation as a key component of their pathology. Additional investigations into the use of supplementation with fish oils in patients with neural injury, cancer, ocular diseases, and critical illness have recently been conducted. The most commonly reported adverse effects of fish oil supplements are a fishy aftertaste and gastrointestinal upset. When recommending an n-3 PUFA, clinicians should be aware of any possible adverse effect or drug interaction that, although not necessarily clinically significant, may occur, especially for patients who may be susceptible to increased bleeding (e.g., patients taking warfarin).

CONCLUSION

The n-3 PUFAs have been shown to be efficacious in treating and preventing various diseases. The wide variation in dosages and formulations used in studies makes it difficult to recommend dosages for specific treatment goals.

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.

ESPEN Guidelines on Parenteral Nutrition: gastroenterology

Undernutrition as well as specific nutrient deficiencies has been described in patients with Crohn's disease (CD), ulcerative colitis (UC) and short bowel syndrome. In the latter, water and electrolytes disturbances may be a major problem. The present guidelines provide evidence-based recommendations for the indications, application and type of parenteral formula to be used in acute and chronic phases of illness. Parenteral nutrition is not recommended as a primary treatment in CD and UC. The use of parenteral nutrition is however reliable when oral/enteral feeding is not possible. There is a lack of data supporting specific nutrients in these conditions. Parenteral nutrition is mandatory in case of intestinal failure, at least in the acute period. In patients with short bowel, specific attention should be paid to water and electrolyte supplementation. Currently, the use of growth hormone, glutamine and GLP-2 cannot be recommended in patients with short bowel.

Site specific delivery of microencapsulated fish oil to the gastrointestinal tract of the rat

The aim of this study was to design food grade matrices to deliver microencapsulated fish oil to the large bowel of the rat where the potential exists to retard inflammation and cancer development. Digestion in simulated gastric fluid and intestinal fluid demonstrated that only 4-6% of oil was released from the following dried emulsion formulations: 50% fish oil encapsulated in heated casein-glucose-dried glucose syrup (1:1:1) (Cas-Glu-DGS-50); 25% fish oil in casein-modified resistant starch (Hylon VII) (1:1) (Cas-Hylon-25); or 25% fish oil in Cas-Glu-Hylon (1:1:1) (Cas-Glu-Hylon-25). A short-term gavage study (0-12 h) with fish oil and Cas-Glu-DGS-50 demonstrated the appearance of fish oil long chain (LC) n-3 polyunsaturated fatty acids (PUFA) into the plasma indicating specific small intestinal absorption with little LC n-3 PUFA reaching the large bowel. In a 2-week-long term, daily gavage study, the bioavailability of fish oil and fish oil in Cas-Glu-DGS-50 or Cas-Hylon-25 demonstrated that fish oil and Cas-Glu-DGS-50 LC n-3 PUFA were incorporated into the tissue of the small intestine and colon, whereas Cas-Hylon-25 was resistant to degradation in the small intestine. The use of modified Hylon VII for targeted colonic delivery was confirmed in the final short-term gavage study (0-14 h) using Cas-Glu-Hylon-25 with [(14)C]-trilinolenin as a marker incorporated into the microcapsules, where up to 60% of the labeled oil reached the large bowel. Depending on the microencapsulating matrix employed, fish oil can be delivered selectively to the small intestine or to a high degree to the large bowel.

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.

Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease

BACKGROUND

The anti-inflammatory effects of n-3 (omega-3 fatty acids, fish oil) have been suggested to be beneficial in chronic inflammatory disorders such as inflammatory bowel disease.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintenance of remission in Crohn's disease (CD).

SEARCH STRATEGY

The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of n-3 for maintenance of remission in CD were included. Studies must have enrolled patients of any age group, who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil or n-3 given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was the relapse rate and secondary outcomes included change in disease activity scores, time to first relapse and adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. Meta-analyses were performed using RevMan 4.2 software weighted by the Mantel-Haenszel method. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed in an attempt to explore possible sources of heterogeneity.

MAIN RESULTS

Six studies were eligible for inclusion. There was a marginal significant benefit of n-3 therapy for maintaining remission (RR 0.77 0.; 95%CI 0.61 to 0.98; P = 0.03). However, the studies were both clinically and statistically heterogeneous (P = 0.03, I(2) = 58%). Two large studies showed negative results. When considering the estimated rather than the observed 1-year relapse rate of these two studies, the benefit was no longer statistically significant (RR 0.59; 95% CI 0.34 to 1.03; P=0.06). A funnel plot suggested publication bias. No serious adverse events were recorded in any of the studies but in a pooled analyses there was a significantly higher rate of diarrhea (RR 1.36 95% CI 1.01 to 1.84) and symptoms of the upper gastrointestinal tract (RR 1.98 95% CI 1.38 to 2.85) in the n-3 treatment group.

AUTHORS' CONCLUSIONS

Omega 3 fatty acids are safe but probably ineffective for maintenance of remission in CD. The existing data do not support routine maintenance treatment of Crohn's disease with omega 3 fatty acids.

Dietary supplements commonly used for prevention

The use of complimentary and alternative medicine is on the rise. This article reviews some of the commonly used herbal supplements and others focusing mainly on disease prevention. A summary table of medical conditions is provided, and when possible, a summary of efficacy and safety is provided to facilitate decision making.

Omega-3 fatty acids exacerbate DSS-induced colitis through decreased adiponectin in colonic subepithelial myofibroblasts

BACKGROUND

Although the immunoregulatory effects of omega-3 fatty acid and adiponectin have been postulated, their role in intestinal inflammation is controversial. The aim of this study was to determine whether dietary fat intake influences activity of colonic inflammation through modulating this system.

METHODS

C57BL/6 mice received dextran sulfate sodium for induction of colitis. Mice were fed a control diet, omega-3 fat-rich diet, omega-6 fat-rich diet, or saturated fat-rich diet. Some mice were administered a peroxisome proliferator activated receptor-gamma; agonist, pioglitazone. Messenger RNA expression of adiponectin and its receptors were analyzed. Adiponectin expression in colonic mucosa of ulcerative colitis patients was also analyzed.

RESULTS

The receptors for adiponectin were found to be ubiquitously expressed in epithelial cells, intraepithelial lymphocytes, lamina proprial mononuclear cells, and subepithelial myofibroblasts from colonic tissue, but adiponectin was only expressed in myofibroblasts. Induction of colitis significantly decreased the expression of adiponectin in colonic mucosa. The omega-3 fat diet group, but not the other fat diet groups, showed exacerbated colitis with a further decrease of adiponectin expression. Pioglitazone treatment ameliorated the level of decrease in adiponectin expression and improved colonic inflammation induced by the omega-3 fat-rich diet. In patients with ulcerative colitis, the expression level of adiponectin in colonic mucosa was also decreased compared with that in control mucosa.

CONCLUSIONS

Adiponectin was found to be expressed in myofibroblasts. Adiponectin expression was significantly suppressed by induction of colitis, and aggravation of colitis after exposure to omega-3 fat may be due to a further decrease in the expression level of adiponectin.

Chronic enteropathy and feeding in children: an update

Enteropathy defines abnormalities of the small intestinal mucosa of various etiologies in which nutrition has a causal or a therapeutic role. Breast milk is the gold-standard feeding during infancy for optimal nutrition in health and the majority of diseases. Therapeutic formulae have decreased the need for enteral or parenteral support. Gastrointestinal infections are worldwide the most frequent cause of enteropathy by increasing mucosal permeability, local expression of costimulatory molecules allowing antigen penetration in the mucosa, and T-cell activation leading sometimes to disruption of oral tolerance. Concomitant malnutrition impairs not only the immunologic response but also the recovery of damaged mucosa with secondary intestinal and pancreatic enzymatic reductions. Optimal nutritional rehabilitation is the cornerstone of the management of persisting diarrhea. Celiac disease and cow's milk protein allergy are examples of chronic enteropathy. Multiple food allergies, even during breast-feeding, are increasingly reported due to an impaired development of oral tolerance. The dietary approach to allergic disease is currently evolving from passive allergen avoidance to active modulation of the immune system to (re)establish tolerance. The gastrointestinal flora provides maturational signals for the lymphoid tissue, improves balance of inflammatory cytokines, reduces bacterial invasiveness and dietary antigen load, and normalizes gut permeability. The clinical effects of nucleotides and zinc merit further clinical evaluation. Major attention has recently focused on the immune effects of dietary lipids in terms of possible prevention of allergic sensitization by downregulating inflammatory response and protecting the epithelial barrier and host-microbe interactions modifying the adherence of microbes to the mucosa.

The contribution of animal fat oxidation products to colon carcinogenesis, through modulation of TGF-beta1 signaling

It is now unanimously accepted that neoplastic cells tend to become less susceptible to the growth regulatory effects of transforming growth factor-beta1 (TGF-beta1), mainly because of reduced expression and/or activity of TGF-beta1-specific receptors, as reported for many human cancers including colon cancer. Consequently, a sustained increase of TGF-beta1 in the intestinal mucosa, like that caused by inflammatory processes and/or high dietary intake of animal fat, might become crucial for the progression of a neoplastic clone. In fact, this proapoptotic and prodifferentiating cytokine could eliminate neoplastic cells still susceptible to TGF-beta1's antiproliferative action (TGF-beta1 receptor-positive cells), indirectly favoring the expansion of TGF-beta1 resistant ones (TGF-beta1 receptors deficient or negative cells). The actual concentration of TGF-beta1 in the colonic mucosa undergoing neoplastic transformation is still debated, and the phase of the relevant carcinogenetic process in which a reduced susceptibility to this antiproliferative molecule first occurs has not been precisely established yet. However, no doubt that TGF-beta1 level and activity may be upregulated in cells of the macrophage lineage by animal fat oxidation products, such as oxysterols and aldehydes, as reviewed here. But phagocytes as well as fibroblasts constitutively express TGF-beta1 and are accumulating in tumor-associated stroma. Thus, upregulation of this cytokine system within colonic tumor-associated stroma by excess dietary intake of cholesterol and n-6 polyunsaturated fatty acids appears as a primary mechanism of cancer progression at least in neoplastic lesions of the digestive tract.

A review of complementary and alternative approaches to immunomodulation

Current Western therapies for inflammatory diseases are suboptimal; increasingly, patients are turning to complementary and alternative medicine for symptom relief and improved quality of life. There is emerging evidence that many of these therapies have the ability to modulate the immune system and disrupt the proinflammatory cascade through a variety of mechanisms, including antioxidant effects, alterations in cell signaling (in particular the nuclear factor (NF)-kappaB pathway), cytokines, proinflammatory mediators, and disruption of bacterial flora. Using inflammatory bowel disease (IBD) as a model of inflammation, we explore the principal complementary and alternative medicine treatments that show promise in this regard, namely, resveratrol, green tea, curcumin, boswellia, fish oil, vitamin D, and probiotics. With each agent, we detail the mechanisms that have been described with regard to immune modulation, discuss the medical conditions for which it has been evaluated, and explore the data to date for the prevention or treatment of IBD.

Integrative medicine in gastrointestinal disease: evaluating the evidence

Current Western therapies for many gastrointestinal diseases are suboptimal and potentially toxic. The majority of patients with digestive diseases are turning to complementary and alternative medicine for symptom relief and improved quality of life, due to dissatisfaction with conventional medical therapies. There is emerging evidence that many of these complementary and alternative medicine modalities are highly effective in modulating the immune system, disrupting the proinflammatory cascade and restoring digestive health while improving patients' quality of life. We present evidence to support the potential utility of complementary and alternative medicine modalities for irritable bowel syndrome and inflammatory bowel disease. For each condition, we detail the proposed mechanisms of action and explore the current data for the prevention and/or treatment of disease.