Nutrition and ulcerative colitis

The Role of Autophagy in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory disease, including ulcerative colitis (UC) and Crohn’s disease (CD). The abnormality of inflammatory and immune responses in the intestine contributes to the pathogenesis and progression of IBD. Autophagy is a vital catabolic process in cells. Recent studies report that autophagy is highly involved in various kinds of diseases, especially inflammation-related diseases, such as IBD. In this review, the biological characteristics of autophagy and its role in IBD will be described and discussed based on recent literature. In addition, several therapies for IBD through modulating the inflammasome and intestinal microbiota taking advantage of autophagy regulation will be introduced. We aim to bring new insight in the exploration of mechanisms for IBD and development of novel therapeutic strategies against IBD.

Sulphate-reducing bacteria from ulcerative colitis patients induce apoptosis of gastrointestinal epithelial cells

The human microbiome consists of a multitude of bacterial genera and species which continuously interact with one another and their host establishing a metabolic equilibrium. The dysbiosis can lead to the development of pathology, such as inflammatory bowel diseases. Sulfide-producing prokaryotes, including sulphate-reducing bacteria (SRB) constituting different genera, including the Desulfovibrio, are commonly detected within the human microbiome recovered from fecal material or colonic biopsy samples. It has been proposed that SRB likely contribute to colonic pathology, for example ulcerative colitis (UC). The interaction of SRB with the human colon and intestinal epithelial cell lines has been investigated using Desulfovibrio indonesiensis as a model mono-culture and in a co-culture with E. coli isolate, and with SRB consortia from human biopsy samples. We find that D. indonesiensis, whether as a mono- or co-culture, was internalized and induced apoptosis in colon epithelial cells. This effect was enhanced in the presence of E. coli. The SRB combination obtained through enrichment of biopsies from UC patients induced apoptosis of a human intestinal epithelial cell line. This response was not observed in SRB enrichments from healthy (non-UC) controls. Importantly, apoptosis was detected in epithelial cells from UC patients and was not seen in epithelial cells of healthy donors. Furthermore, the antibody raised against exopolysaccharides (EPS) of D. indonesiensis cross reacted with the SRB population from UC patients but not with the SRB combination from non-UC controls. This study reinforces a correlation between the presence of sulphate-reducing bacteria and an inflammatory response in UC sufferers.

Intracellular mechanisms involved in docosahexaenoic acid-induced increases in tight junction permeability in Caco-2 cell monolayers

We recently showed that enrichment of Caco-2 cells with docosahexaenoic acid (DHA) increases lipid peroxidation and the formation of hydrogen peroxide and peroxynitrite, which disrupt the epithelial barrier function. Studies were designed to test whether the participation of phospholipase C (PLC)/Ca(2+)/protein kinase C (PKC), cyclooxygenase (COX), and 5-lipooxygenase pathways are involved in mediating the effects of DHA. Paracellular permeability was assessed from D-mannitol flux and transepithelial electrical resistance (TER) in differentiated Caco-2 cell monolayers incubated in control or DHA-enriched conditions (100 micromol/L). The effect of DHA was prevented by U73122 (PLC inhibitor), chelerytrine (PKC inhibitor), and 1-[5-iodonaphtalene-1-sulfonyl]-1H-hexahydro-1,4-diazepine hydrochloride (myosin light chain kinase inhibitor). In contrast, the effect of DHA was enhanced by A23187 (Ca(2+) ionophore) and BAPTA-AM (Ca(2+) chelator). Indomethacin (COX inhibitor) and AA961 (5-lipooxygenase inhibitor) also prevented the changes in D-mannitol flux induced by DHA, but no effect was detected for TER. Moreover, occludin and ZO-1 immunogold staining microscopy showed that the increase in paracellular permeability was accompanied by the redistribution of both tight junction proteins. We conclude that the disruption of epithelial barrier function by DHA is partly mediated by the PLC/Ca(2+)/PKC pathway and by the formation of eicosanoids.

Nutritional follow-up of patients with ulcerative colitis during periods of intestinal inflammatory activity and remission

CONTEXT: Ulcerative colitis is an inflammatory bowel disease involving superficial inflammation of the mucosa of the colon, rectum, and anus, sometimes including the terminal ileum. When in clinical activity, the disease is characterized by various daily evacuations containing blood, mucus and/or pus alternating periods of remission. OBJECTIVE: To compare nutritional parameters (dietary, biochemical and anthropometric) among patients with ulcerative colitis followed up on an outpatient basis over a period of 1 year and during periods of intestinal inflammatory activity and remission. METHODS: Sixty-five patients were studied over a period of 1 year and divided into two groups: group 1 with inflammatory disease activity (n = 24), and group 2 without disease activity (n = 41). Anthropometric measures, biochemical parameters, quantitative food intake, and qualitative food frequency were analyzed. RESULTS: A significant reduction in body mass index and weight and in the intake of energy, proteins, lipids, calcium, iron and phosphorus was observed in the group with inflammatory activity (group 1) when compared to the period of clinical remission. The most affected food groups were cereals, legumes, oils, and fats. In contrast, in group 2 significant differences in triceps and sub scapular skin fold thickness, total protein, hemoglobin and hematocrit were observed between the first and final visit. Calcium and vitamin B6 intake, as well as the consumption of legumes, meat and eggs, and sugar and sweets, was significantly higher than on the first visit. CONCLUSION: Patients with ulcerative colitis followed up on an outpatient basis tend to be well nourished. However, the nutritional aspects studied tend to worsen during the period of inflammatory disease activity.

Nationwide prevalence and prognostic significance of clinically diagnosable protein-calorie malnutrition in hospitalized inflammatory bowel disease patients

BACKGROUND

Inflammatory bowel disease (IBD) patients are at increased risk of protein-calorie malnutrition. We sought to determine the prevalence of clinically diagnosable malnutrition among those hospitalized for IBD throughout the United States and whether this malnutrition influenced health outcomes.

METHODS

We queried the Nationwide Inpatient Sample between 1998 and 2004 to identify admissions for Crohn's disease (CD) or ulcerative colitis (UC) and a representative sample of non-IBD discharges. We assessed the prevalence and predictors of malnutrition and its association with in-hospital mortality and resource utilization.

RESULTS

The prevalence of malnutrition was greater in CD and UC patients than in non-IBD patients (6.1% and 7.2% versus 1.8%, P < 0.0001). The adjusted odds ratio for malnutrition among IBD admissions compared with non-IBD admissions was 5.57 [95% confidence interval (CI): 5.29-5.86]. More IBD discharges than non-IBD discharges with malnutrition received parenteral nutrition (26% versus 6%, P < 0.0001). There was increased likelihood of malnutrition among those with fistulizing CD (OR 1.65; 95% CI: 1.50-1.82) and among those who had undergone bowel resection (OR 1.37; 95% CI: 1.27-1.48). Malnutrition was associated with increased in-hospital mortality 3.49 (95% CI: 2.89-4.23), length of stay (11.9 days versus 5.8 days, P < 0.00001), and total charges ($45,188 versus $20,295, P < 0.0001).

CONCLUSIONS

Clinically apparent malnutrition is more frequent among IBD admissions than among non-IBD admissions. Its association with greater mortality and resource utilization may reflect more severe underlying disease that can lead to both malnutrition and worse outcomes. Nonetheless, diagnosable malnutrition may serve as a clinical marker of poor IBD prognosis in hospitalized patients.

In vitro determination of prebiotic properties of oligosaccharides derived from an orange juice manufacturing by-product stream

Fermentation properties of oligosaccharides derived from orange peel pectin were assessed in mixed fecal bacterial culture. The orange peel oligosaccharide fraction contained glucose in addition to rhamnogalacturonan and xylogalacturonan pectic oligosaccharides. Twenty-four-hour, temperature- and pH-controlled, stirred anaerobic fecal batch cultures were used to determine the effects that oligosaccharides derived from orange products had on the composition of the fecal microbiota. The effects were measured through fluorescent in situ hybridization to determine changes in bacterial populations, fermentation end products were analyzed by high-performance liquid chromatography to assess short-chain fatty acid concentrations, and subsequently, a prebiotic index (PI) was determined. Pectic oligosaccharides (POS) were able to increase the bifidobacterial and Eubacterium rectale numbers, albeit resulting in a lower prebiotic index than that from fructo-oligosaccharide metabolism. Orange albedo maintained the growth of most bacterial populations and gave a PI similar to that of soluble starch. Fermentation of POS resulted in an increase in the Eubacterium rectale numbers and concomitantly increased butyrate production. In conclusion, this study has shown that POS can have a beneficial effect on the fecal microflora; however, a classical prebiotic effect was not found. An increase in the Eubacterium rectale population was found, and butyrate levels increased, which is of potential benefit to the host.

An oral supplement enriched with fish oil, soluble fiber, and antioxidants for corticosteroid sparing in ulcerative colitis: a randomized, controlled trial

BACKGROUND & AIMS

N-3 fatty acids from fish oil, antioxidants, and short-chain fatty acids (SCFAs) produced during the fermentation of soluble fiber may attenuate inflammation associated with ulcerative colitis (UC). We assessed the efficacy of a nutritionally balanced oral supplement enriched with fish oil, fructooligosaccharides, gum arabic, vitamin E, vitamin C, and selenium on disease activity and medication use in adults with mild to moderate UC.

METHODS

A total of 121 patients with UC and a disease activity index (DAI) from 3-9 on a 12-point scale were block randomized for extent of disease and smoking status. In addition to their usual diet, patients consumed 18 oz of the oral supplement or a carbohydrate-based placebo formula each day for 6 months. Clinical and histologic responses were assessed at 3 and 6 months or at the final visit. A change in average prednisone use between groups was tested by using a linear mixed-effects model.

RESULTS

Eighty-six patients completed the study. Baseline characteristics were not different between groups except for a higher total DAI score in the oral supplement group (7.3 +/- 1.3; n = 36) compared with the placebo group (6.2 +/- 2.0; n = 50) ( P < .05). Both groups showed significant and similar degree of improvement at 6 months in DAI (-2.5 for oral supplement and -2.8 for placebo) and histologic index (-1.9 for oral supplement vs. -2.0 for placebo). Both intent-to-treat and completed patients given oral supplement had a significantly greater rate of decrease in the dose of prednisone required to control clinical symptoms over 6 months as compared with the placebo group ( P < .001).

CONCLUSIONS

The improvement in clinical response combined with a decreased requirement for corticosteroids suggest that this enriched oral supplement can be a useful adjuvant therapy in patients with UC.

Polyunsaturated fatty acids and inflammatory diseases

Inflammation is overall a protective response, whose main goal is to liberate the human being of cellular lesions caused by micro-organisms, toxins, allergens, etc., as well as its consequences, and of death cells and necrotic tissues. Chronic inflammation, which is detrimental to tissues, is the basic pathogenic mechanism of hypersensitivity reactions against xenobiotics. Other frequent pathologies, for instance atherosclerosis, chronic hepatitis, inflammatory bowel disease (IBD), liver cirrhosis, lung fibrosis, psoriasis, and rheumatoid arthritis are also chronic inflammatory diseases. Chemical mediators of inflammation are derived from blood plasma or different cell-type activity. Biogenic amines, eicosanoids and cytokines are within the most important mediators of inflammatory processes. The different activities of eicosanoids derived from arachidonic acid (20:4 n-6) versus those derived from eicosapentaenoic acid (20:5 n-3) are one of the most important mechanisms to explain why n-3, or omega-3, polyunsaturated fatty acids (PUFA) exhibit anti-inflammatory properties in many inflammatory diseases. Dietary supplements ranging 1-8 g per day of n-3 PUFA have been reportedly beneficial in the treatment of IBD, eczema, psoriasis and rheumatoid arthritis. In addition, recent experimental studies in rats with experimental ulcerative colitis, induced by intrarectal injection of trinitrobenzene sulphonic acid, have documented that treatment with n-3 long-chain PUFA reduces mucosal damage as assessed by biochemical and histological markers of inflammation. Moreover, the defence antioxidant system in this model is enhanced in treated animals, provided that the n-3 PUFA supply is adequately preserved from oxidation.

Effect of dietary fatty acids on the intestinal permeability of marker drug compounds in excised rat jejunum

The aim of this study was to explore the effects of diets containing saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and omega-3 and omega-6 polyunsaturated fatty acids (omega-3 and omega-6 PUFA, respectively) on the passive and active transport properties of rat jejunum using marker compounds. Rats were fed diets supplemented with 18.4% (w/w) lipid (4 groups) or standard rat chow (1 group) for a period of 30 days. At the end of the dietary period, mucosal scrapings were taken for the determination of membrane phospholipids, and the apparent jejunal permeability of radiolabelled marker compounds was determined using modified Ussing chambers. Changes in the phospholipid content of the brush border membrane reflected the different lipid content of the diets. The passive paracellular permeability of mannitol was not significantly affected by the fatty acid composition of the diet, although there was a trend toward decreased mannitol permeability in the rats fed both the omega-3 and omega-6 PUFA diets. In comparison, the transcellular diffusion of diazepam was reduced by 20% (P < 0.05) in rats fed diets supplemented with omega-3 and omega-6 PUFA. In the lipid-fed rats, the serosal to mucosal flux of digoxin, an intestinal P-glycoprotein substrate, was reduced by 20% (P < 0.05) relative to the chow-fed group, however there were no significant differences between the different lipid groups. The active absorption of D-glucose via the Na+-dependent transport pathway was highest in the SFA, MUFA and PUFA omega-3 dietary groups, intermediate in the low-fat chow group and lowest in the PUFA omega-6 group, and was positively correlated with short-circuit current. These studies indicate that dietary fatty acid changes can result in moderate changes to the active and passive transport properties of excised rat jejunum.

Dietary polyunsaturated fatty acids improve histological and biochemical alterations in rats with experimental ulcerative colitis

The aim of the present study was to determine whether dietary intake of monounsaturated (MUFA) and/or polyunsaturated fatty acids (PUFA) of the (n- 3) and (n-6) series could improve intestinal damage and reduce inflammation in experimental ulcerative colitis (UC). Rats were treated with 80 mg/kg body of 2,4,6-trinitrobenzenesulfonic acid and fed for 1 or 2 wk diets enriched in olive oil (OO), fish oil (FO), or purified pig brain phospholipids (BPL), as sources of monounsaturated and PUFA of the (n-3) and (n-3) + (n-6) series. Evaluation of macroscopic and microscopic colonic damage was assessed. Ultrastructural and histologic changes were analyzed as well as plasma and colonic mucosa fatty acid profiles and some biochemical markers of injury and inflammation [alkaline phosphatase (AP), mieloperoxidase (MPO), prostaglandin E(2) (PGE(2)) and leukotriene B(4)]. Fatty acid profiles of both plasma and mucosa mostly reflected the dietary fatty acid composition. Plasma MUFA proportions were higher in UC animals fed the OO diet compared with FO or BPL groups 1 and 2 wk and (n-3) long chain PUFA (LC-PUFA) were higher in the FO than in the OO and BPL groups. At 1 wk, UC led to lower MUFA mucosa levels and (n-3)LC-PUFA were higher in the FO group compared with the OO and BPL groups. Rats with UC fed FO at 1 wk showed significantly less macroscopic and microscopic colonic damage. They also have lower AP and MPO activities and PGE(2) levels compared with the OO and BPL groups and showed enhanced histological repair, less necrotic areas within the mucosa, and more goblet cells with mature mucin granules. These results suggest that the use of balanced diets containing (n-3) LC-PUFA could ameliorate the inflammation and mucosal damage in UC.

Oligofructose and long-chain inulin: influence on the gut microbial ecology of rats associated with a human faecal flora

Dietary incorporation of fermentable, indigestible fructans may be of benefit to gastrointestinal health by providing short-chain fatty acids, stimulating the proliferation of bifidobacteria or lactobacilli and suppressing potential pathogenic organisms in the gut. We tested the hypothesis that the effects of fructans on caecal, colonic and faecal short-chain fatty acid concentration and microflora composition depend on their chain length. Germ-free rats associated with a human faecal flora were randomly assigned to one of four treatments as follows: (1) commercial standard diet as a control (Con); (2) Con+50 g short-chain oligofructose/kg (OF); (3) C+50 g long-chain inulin/kg (lcIN); or (4) Con+50 g OF-lcIN/kg (Mix OF-lcIN). Changes in bacterial population groups in response to feeding these diets were investigated with 16S rRNA-targeted probes applied in in situ hybridization. Mix OF-lcIN- and lcIN-containing diets resulted in larger numbers of caecal, colonic and faecal bacteria of the Clostridium coccoides-Eubacterium rectale cluster than Con (10.6 and 10.3 v. 9.5 log10/g wet wt), whereas OF alone did not affect this bacterial group in caecum, colon or faeces. A bifidogenic effect was only observed in the colon and faeces of OF-treated rats. More lactobacilli were found in caecal and colonic contents of Mix OF-lcIN-fed rats and in faeces of OF-fed rats compared with Con. Mix OF-lcIN and OF led to significantly smaller numbers of caecal, colonic and faecal bacteria belonging to the Clostridium histolyticum and C. lituseburense groups than Con (6.8 and 6.9 v. 7.9 log10/g wet wt). Counts of total bacteria, Bacteroides-Prevotella and Enterobacteriaceae did not differ between the groups. OF and/or lcIN-containing diets significantly increased the caecal and colonic concentration of butyrate and its relative molar proportion. Only lcIN-containing diets resulted in a higher faecal concentration of butyrate than Con. Higher molar proportions of faecal butyrate were observed with all diets that had been supplemented with OF and/or lcIN. Stimulation of butyrate production could be of interest for the prevention of ulcerative colitis and colon cancer.

Jejunal feeding, even when instituted late, improves outcomes in patients with severe pancreatitis and peritonitis

This study assessed the feasibility and effectiveness of jejunal feeding (JF) after surgery due to secondary peritonitis or failed conservative therapy of severe pancreatitis. Of 60 patients, 30 were randomly assigned to receive postoperative JF and the remaining 30 constituted the control group. Acute Physiology and Chronic Health Evaluation II, nutritional intake, systemic inflammatory response syndrome, and outcomes were measured. Patients in JF group received the daily mean of 1294.6 (362.6) kcal including 830.6 (372.7.0) kcal enterally, versus 472.8 (155.8) kcal daily in the control group (P < 0.0001). There were fewer complications in the JF patients, with no significant difference; length of stay in the intensive care unit and in the hospital did not differ. The frequency of systemic inflammatory response syndrome was similar in both groups, but outcomes differed. The first surgical intervention resulted in 3.3% of relaparotomies in JF patients, caused by unresolved peritonitis, versus 26.7% in the control subjects (P = 0.03). Recovery of bowel transit took significantly less time in the JF patients (mean: 54.6 h versus 76.8 h in control subjects, P = 0.01). JF resulted in 3.3% mortality as opposed to 23.3% in the control group (P = 0.05). In conclusion, JF is feasible and effective in postoperative treatment of patients due to secondary peritonitis or severe pancreatitis. Improved bowel and peritoneal function could be the main impact of JF.

Comparative tolerability of treatments for inflammatory bowel disease

Despite limited understanding of therapeutic aetiopathogenesis of ulcerative colitis and Crohn's disease, there is a strong evidence base for the efficacy of pharmacological and biological therapies. It is equally important to recognise toxicity of the medical armamentarium for inflammatory bowel disease (IBD). Sulfasalazine consists of sulfapyridine linked to 5-aminosalicylic acid (5-ASA) via an azo bond. Common adverse effects related to sulfapyridine 'intolerance' include headache, nausea, anorexia, and malaise. Other allergic or toxic adverse effects include fever, rash, haemolytic anaemia, hepatitis, pancreatitis, paradoxical worsening of colitis, and reversible sperm abnormalities. The newer 5-ASA agents were developed to deliver the active ingredient of sulfasalazine while minimising adverse effects. Adverse effects are infrequent but may include nausea, dyspepsia and headache. Olsalazine may cause a secretory diarrhoea. Uncommon hypersensitivity reactions, including worsening of colitis, pancreatitis, pericarditis and nephritis, have also been reported. Corticosteroids are commonly prescribed for treatment of moderate to severe IBD. Despite short term efficacy, corticosteroids have numerous adverse effects that preclude their long term use. Adverse effects include acne, fluid retention, fat redistribution, hypertension, hyperglycaemia, psycho-neurological disturbances, cataracts, adrenal suppression, growth failure in children, and osteonecrosis. Newer corticosteroid preparations offer potential for targeted therapy and less corticosteroid-related adverse effects. Azathioprine and mercaptopurine are associated with pancreatitis in 3 to 15% of patients that resolves upon drug cessation. Bone marrow suppression is dose related and may be delayed. The adverse effects of methotrexate include nausea, leucopenia and, rarely, hypersensitivity pneumonia or hepatic fibrosis. Common adverse effects of cyclosporin include nephrotoxicity, hypertension, headache, gingival hyperplasia, hyperkalaemia, paresthesias, and tremors. These adverse effects usually abate with dose reduction or cessation of therapy. Seizures and opportunistic infections have also been reported. Antibacterials are commonly employed as primary therapy for Crohn's disease. Common adverse effects of metronidazole include nausea and a metallic taste. Peripheral neuropathy can occur with prolonged administration. Ciprofloxacin and other antibacterials may be beneficial in those intolerant to metronidazole. Newer immunosuppressive agents previously reserved for transplant recipients are under investigation for IBD. Tacrolimus has an adverse effect profile similar to cyclosporin, and may cause renal insufficiency. Mycophenolate mofetil, a purine synthesis inhibitor, has primarily gastrointestinal adverse effects. Biological agents targeting specific sites in the immunoinflammatory cascade are now available to treat IBD. Infliximab, a chimeric antibody targeting tumour necrosis factor-or has been well tolerated in clinical trials and early postmarketing experience. Additional trials are needed to assess long term adverse effects.

Polyunsaturated fatty acids reduce non-receptor-mediated transcellular permeation of protein across a model of intestinal epithelium in vitro

BACKGROUND

Dietary polyunsaturated fatty acids influence the natural history of intestinal inflammatory diseases. Varying the types of long-chain fatty acids that are exposed to cells alters the physicochemical properties of cell membranes. This study aimed to determine whether such variations alter transcellular and paracellular permeability in intestinal epithelium.

METHODS

Monolayers of Caco-2 cells, allowed to differentiate by culturing for 7 days following confluence, were used as the model for intestinal epithelium. Paracellular permeability was assessed by measurement of transepithelial resistance, while transcellular permeability was assessed by the transepithelial flux of horseradish peroxidase.

RESULTS

Exposure of the cells to 100 micromol/L of palmitic acid, oleic acid, eicosapentaenoic acid, or linoleic acid, was not toxic to cells (measured by leakage of lactate dehydrogenase), and altered cell membrane fatty acid composition (as measured by gas chromatography). Flux of horseradish peroxidase was significantly affected by 24 h fatty acid exposure (P= 0.038, ANOVA), being decreased by 23 +/- 6% (mean +/- SEM) by eicosapentaenoic acid and 25 +/- 3% by linoleic acid. Oleic acid, palmitic acid and butyrate, had no effect. Transepithelial resistance also varied significantly across the treatment groups (P< 0.001) due to a 28 +/- 5% increase induced by butyrate. The long-chain fatty acids had no effect.

CONCLUSIONS

Both omega-3 and omega-6 polyunsaturated fatty acids reduce transcellular, non-receptor-mediated permeation of proteins across differentiated Caco2 cell monolayers, without altering paracellular permeability. Alteration of intestinal barrier function should be considered as a possible mechanism of action of dietary polyunsaturated fatty acids.

Therapeutic potential of infliximab in inflammatory bowel disease

Traditional treatment approaches for patients with inflammatory bowel disease involve 1) pharmacologic management with aminosalicylates, corticosteroids, immunomodulatory agents, and antibiotics; and 2) nonpharmacologic management by surgical and dietary means. Complications and inadequate responses to current treatment modalities have resulted in the development of new and more specific biologic therapies. The proinflammatory cytokine tumor necrosis factor alpha (TNF alpha) is present in elevated concentrations in patients with inflammatory bowel disease; therefore, it has been targeted for treatment approaches. Infliximab is a chimeric, monoclonal antibody to TNF alpha developed to inhibit the interaction of TNF alpha with its receptor, to result in amelioration of inflammation. This biologic agent has received the most attention and is the most studied of those for the treatment of patients with Crohn's disease. This article reviews the symptoms of inflammatory bowel disease, the traditional treatment approaches used, the role of TNF alpha in disease pathogenesis, and the value of infliximab in treatment.

Antioxidants and mucosa protectives: realistic therapeutic options in inflammatory bowel disease?

Oxidative damage is involved in the pathogenic process of idiopathic chronic inflammatory bowel disease. Although specific intervention in the oxidative cascade showed promising results in animal models and preliminary patient trials, the clinical efficacy of antioxidants still has to be established. Mucosa protection, for example by dietary fatty acids, seems to attenuate the intestinal inflammatory process as well but awaits definite clinical proof for the treatment of inflammatory bowel disease.