Omega Fatty Acids and Inflammatory Bowel Diseases: An Overview

Abstract

Inflammatory bowel diseases (IBD) are chronic, inflammatory processes that affect the gastrointestinal tract and are mainly represented by ulcerative colitis (UC) and Crohn's disease (CD). Omega 3 (ω3) fatty acids (eicosapentanoic acid and docosahexaenoic acid) show an indispensable role in the inflammatory processes and, for these reasons, we aimed to review the effects of these acids on UC and CD. Databases such as PUMED and EMBASE were searched, and the final selection included fifteen studies that fulfilled the inclusion criteria. The results showed that ω3 fatty acids reduce intestinal inflammation, induce and maintain clinical remission in UC patients, and are related with the reduction of proinflammatory cytokines, decrease disease activity and increase the quality of life of CD patients. Furthermore, the consumption of these fatty acids may be related to a reduced risk of developing IBD. Many studies have shown the beneficial effects of ω3 as adjunctive in the treatment or prevention of UC or CD. Nevertheless, most were performed with a small number of patients and there are many variations in the mode of consumption, the type of food or the type of formulation used. All these factors substantially interfere with the results and do not allow reliable comparisons.

Keywords: crohn’s disease; docosahexaenoic acid; eicosapentaenoic acid; omega 3; ulcerative colitis.

Figure 1

Pathophysiologic aspects of inflammatory bowel disease IBD. The disruption in tight junctions results in increased permeability of the epithelial cells leading to an augment in the uptake of antigens and activation of dendritic cells and macrophages, accompanied by decreased release of anti-inflammatory cytokines such as IL-10 and TGF-β, and increased release of proinflammatory cytokines such as INF-γ, TNF-α, IL-4, IL-5, IL-9, IL-17, and IL-22 (modified from Barbalho et al. 2018 [16]). IL: Interleukin; TGF-β: transforming growing factor-β; INF-γ: interferon-γ; TNF-α: tumor necrosis factor-α.

Figure 2

Structure of some fatty acids. ω6 (linoleic acid): first double bond at the sixty-carbon molecule from the methyl end of the chain; ω3 series (linolenic acid, C18:3; eicosapentaenoic acid, C20:5; docosahexaenoic acid, C22:6): first double bond at the third carbon molecule from the methyl end of the chain.

Figure 3

Eicosanoids from the ω3 family. ω3 series prostanoids are PGE3, PGI3, and TXA3; and ω5 series leukotrienes are LTB5 and LTC5. PGE3: prostaglandin E3; PGI3: prostaglandin I3; TXA3: thromboxane A3; LTB5: leukotriene B5; LTC5: leukotriene C5; COX: cyclooxygenase; LOX: lipoxygenase; CYP450: cytochrome P450 (modified from Barbalho et al., 2016 [2]).

Figure 4

Flow diagram showing the results of the search according to PRISMA guidelines [48].