Flaxseed contains two components that favourably affect the immune system: alpha-linolenic acid (ALA), an essential omega-3 fatty acid, and lignans, a type of phytoestrogen. These components affect immune cells and mediators of the immune response such as eicosanoids and cytokines. ALA, for example, suppresses the proliferation of peripheral blood mononuclear lymphocytes and the delayed hypersensitivity response to certain antigens. Recent research suggests that ALA and lignans in flaxseed modulate the immune response and may play a beneficial role in the clinical management of autoimmune diseases.

Flaxseed Effects on the Immune System
The ALA component of flaxseed influences immunity — the body’s ability to defend itself successfully against foreign substances — through its effects on membrane phospholipids and the production of eicosanoids and cytokines. Lignans influence certain mediators of the immune response.

Membrane Phospholipids
ALA and other omega-3 fatty acids influence the immune response by altering the fatty acid composition of membrane phospholipids, which in turn significantly affects eicosanoid production. ALA in flaxseed increases phospholipid ALA, EPA and DHA levels in mononuclear cells, neutrophils, lipoproteins, and platelets. This change in
membrane phospholipid content results in reduced biosynthesis of arachidonic acid from linoleic acid and decreased production of the proinflammatory eicosanoids, leukotriene B4 (LTB4) and thromboxane A2 (TXA2), shown in Figure 1. Increasing the ALA and omega-3 fatty acid content of membrane phospholipids enhances the biosynthesis of prostaglandin I3 (PGI3) and other eicosanoids of the 3- and 5-series that are less inflammatory.