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


RESULTS
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.


CONCLUSIONS
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.
Laboratory of Nutritional Immunology and Molecular Nutrition, Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. jbassaga@vt.edu
Josep
J
Bassaganya-Riera
Raquel
R
Hontecillas
D000818:Animals; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000276:immunology; D019587:Dietary Supplements; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000378:metabolism; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology / Q000627:therapeutic use*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000378:metabolism
D015525:Fatty Acids, Omega-3; D044243:Linoleic Acids, Conjugated; D047492:Peroxisome Proliferator-Activated Receptors