Dietary fats provide the building blocks for hormone- like molecules produced by cells of the immune system. These hormone- like molecules (cytokines) provide the means by which the immune system communicates with itself, as well as with other body tissues.  

Historically humans consumed a diet which delivered equal proportions of Omega-3 and Omega-6 fatty acids. Modern North American society consumes a diet which contains approximately 20 times more Omega-6 fat relative to Omega-3 fat. This profound difference in dietary fat selection has powerful impact on the function of the human immune system.

Cytokines made from the Omega-6 fat arachidonic acid (AA) are considered pro- inflammatory. An overproduction of cytokines from AA results in worsening of conditions such as arthritis, inflammatory bowel disease, asthma, psoriasis, eczema, and others. Omega-3 fatty acids can also give rise to cytokines. The cytokines produced by Omega-3 fatty acids (specifically eicosapentaenoic acid- EPA) act in the opposite manner as AA- derived cytokines. Not surprisingly human studies have shown that fish oil supplementation benefits the list of disorders described above.