Alleviation of Autoimmune Disease by Dietary Lipids Containing Omega-3 Fatty Acids

Elevated concentrations of linoleic acid in erythrocyte membrane phospholipids in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn disease (CD), is a disorder characterized by diffuse inflammation of the gastrointestinal tract. The immune response and inflammation are mediated by polyunsaturated fatty acids and influenced by dietary fats and lipid metabolism. This study examined the qualitative and quantitative fat intake of IBD patients and healthy controls on plasma phospholipid and erythrocyte membrane phospholipid (EMP) fatty acid content. Measurement of the fatty acid composition of plasma phospholipid and EMP were performed in 29 UC patients, 20 CD patients, and 31 healthy controls. Anthropometric characteristics and data on dietary intake were also collected. We observed significantly lower lipid intake in UC and CD patients vs controls. The UC and CD patients had significantly higher levels of linoleic acid in their EMP than did controls. There were no significant differences in the levels of n-3 polyunsaturated fatty acids, but there were significantly higher levels of the n-6 in the EMP of UC and CD patients compared with controls. The significant differences persisted after the data were adjusted for potential confounders and lipid intake. Higher levels of linoleic acids and n-6 fatty acids, which are involved in production of proinflammatory mediators, were found in IBD patients compared with controls, thereby implicating n-6 fatty acids in the pathophysiology of the disease.

Oxidative damage in rat tissue following excessive L-tryptophan and atherogenic diets

Numerous reports were published on the connection between diets containing excessive L-tryptophan and the development of Eosinophilia Myalgia Syndrome. It has been also demonstrated that some cell functions depend on fatty acid composition which can result in increased lipid peroxidation in cells such as macrophages and other inflammatory cells. The purpose of the present study was to investigate the combined effects of an atherogenic diet enriched with tryptophan on lipid peroxidation in rats. 3-week-old CD-1 female rats were fed (3 weeks) control or atherogenic diets and the same diets supplemented with 0.4% or 1.0% L-tryptophan. Liver and skeletal muscle samples from all groups were taken for histology, autoradiography and for determination of lipid peroxidation. Infiltration of cells into fascia of muscle was observed following tryptophan or atherogenic diet consumption. However, no change in 3H-thymidine incorporation into DNA was observed by autoradiography. A significant increase of lipid peroxidation was detected in muscle following consumption of L-tryptophan-rich diets, with no significant difference from control in animals treated with atherogenic diets. Contrastly, a reduced lipid peroxidation was detected in liver of animals treated with excessive tryptophan as well as in animals fed on L-tryptophan and atherogenic diet or atherogenic diet alone. Our results indicated that excessive dietary tryptophan, when consumed with an atherogenic diet, increased lipid peroxidation in muscle but not in liver. Consumption of these feeding diets with or without supplementation of tryptophan resulted in reduced lipid peroxidation in muscle as well as in liver.

Diets, dietary supplements, and nutritional therapies in rheumatic diseases

Rheumatoid arthritis and many other systemic rheumatic diseases remain illnesses of unknown cause for which current therapy is often inadequate. This leads patients to seek questionable remedies, prominent among which are dietary manipulations. Is there a role for dietary modifications in the routine therapy for patients with rheumatic diseases? This article discusses the relationships between diets, fasting, elemental nutrition, vitamins, minerals, and foods for rheumatic diseases. Known scientific-based evidence for the use, safety, and efficacy of diets and dietary-related practices subscribed by patients with rheumatic diseases are presented. Studies that link diet with arthritis offer the possibility of identifying new therapeutic approaches for selected patients and of developing new insights to disease pathogenesis. Dietary therapy for arthritis, however, is still being investigated.

Omega-3 fatty acids in rheumatoid arthritis: an overview

OBJECTIVES

To review background, pharmacological properties, mechanisms of action, and published clinical experience using omega-3 fatty acids in rheumatoid arthritis.

MATERIALS AND METHODS

English language publications were identified through a computerized search (using MEDLINE) between 1979 and 1995 using the terms "omega-3 fatty acids" and "fish oil". In addition, manual search and cross references were used to obtain published articles on the subject. Papers showing evidence of pharmacological properties and mechanisms of action were analyzed. For therapeutic efficacy, only randomized clinical trials are presented in this article. All papers were reviewed by a board certified rheumatologist with training in research methodology and critical appraisal skills. He was aware of study objectives.

RESULTS

Main results are summarized in the text and presented in tables. Mean change from baseline is presented only for patients treated with omega-3 fatty acids. Omega-3 fatty acids are superior with respect to placebo in improving some outcome measures, and decrease the long-term requirements for nonsteroidal antiinflammatory drugs. Some of these effects are statistically significant, but their clinical significance remain to be established.

CONCLUSIONS

Treatment with omega-3 fatty acids has been associated with improvement in some outcome measures in rheumatoid arthritis. Studies are needed to determine if they might represent an alternative to nonsteroidal antiinflammatory drugs in certain circumstances.

Dietary marine lipids suppress continuous expression of interleukin-1 beta gene transcription

n-3 Polyunsaturated fatty acids abundant in marine lipids suppress certain inflammatory and immune reactions, and dietary marine lipid supplements have antiinflammatory effects in experimental and human autoimmune disease. Previous work by other investigators demonstrated that dietary marine lipid supplements suppressed production of cytokines from stimulated human peripheral blood mononuclear cells ex vivo. The present study further documents the ability of n-3 fatty acids to inhibit cytokine formation, and in part defines the mechanism of the inhibition of production of interleukin-1 beta (IL-1 beta) by dietary n-3 fatty acid. Female BALB/c mice were each fed a fat-free balanced diet to which was added either a refined fish oil (FO) preparation as a source of n-3 fatty acid, or beef tallow (BT), which consisted primarily of saturated and monoenoic fatty acids. After ingesting the experimental diets for periods ranging from 3 to 12 wk. spleen cell preparations were stimulated ex vivo with either lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA), and proIL-1 beta mRNA (IL-1 beta mRNA) was measured by northern analysis. Levels of IL-1 beta mRNA in both LPS- and PMA-stimulated cells from BT-fed mice were elevated to a greater extent than in cells from FO-fed mice, at most concentrations of LPS and PMA. Stability of LPS-stimulated mRNA levels after actinomycin D was similar for BT and FO groups, indicating that lower levels of IL-1 mRNA with FO groups was related to suppressed IL-1 gene transcription and not due to accelerated transcript degradation. Nuclear run-on transcription assays revealed a more transient expression of the IL-1 beta gene in LPS-stimulated spleen cells from FO-fed mice compared to cells from BT-fed mice. We conclude that dietary marine lipids reduce transient expression of the IL-1 beta gene in stimulated splenic monocytic cells. Preliminary results from nuclear run-on transcription assays indicate that n-3 fatty acids may not change the initial rate of gene transcription but may promote more rapid shutting down of transcription of this gene after induction than do alternative lipids.

Abnormal plasma polyunsaturated fatty acid pattern in non-active inflammatory bowel disease

An abnormal plasma polyunsaturated fatty acid pattern (PUFA) (increased n3 and decreased n6 PUFA) has been reported in active inflammatory bowel disease (IBD). The possibility of a primary defect in the PUFA metabolism in IBD was hypothesised. The aim of this study was to assess plasma PUFA pattern in inactive inflammatory bowel disease and to ascertain whether patients who had had a colectomy and who were suffering from ulcerative colitis have a similar PUFA pattern than those patients with non-active ulcerative colitis and who had not had a colectomy. Plasma fatty acids were analysed by semi-capillary column gas-liquid chromatography in three groups of patients with inactive IBD (24 patients with inactive ulcerative colitis who had not had a colectomy, 15 patients with ulcerative colitis who had had a colectomy, and 27 patients with Crohn's disease). Plasma concentration and percentage of C22:6n3 and unsaturation index were significantly higher in patients with inactive ulcerative colitis without a colectomy and the Crohn's disease group (p < 0.0001) than in controls. Plasma concentration and percentage of C22:6n3 and the unsaturation index remained significantly higher, in both the operated and non-operated ulcerative colitis patients when compared with controls (p < 0.0001). These results suggest that in inactive IBD, an increased PUFA biosynthesis might be the cause of the high values of n3 compounds. These findings although seen in active disease, are more noticeable in remission because of the lack of artefactual factors (malnutrition, steroids, inflammation). In addition, persistence of high values in both groups of ulcerative colitis patients--that is, those who had had a colectomy and those who had not suggests the existence of a primary abnormality in the PUFA metabolism in IBD.