Arachidonic Acid fatty acid benefit and side effects
May 12 2016 by Ray Sahelian, M.D.

Arachidonic acid is an omega-6 fatty acid found in a number of foods. I think most Americans consume too much of this fatty acid.

Arachidonic acid and prostate cancer
Adding arachidonic acid, a common omega-6 polyunsaturated fatty acid, to culture media causes prostate cancer cells to grow twice as fast. The omega-6 turns on a dozen inflammatory genes that are known to be important in cancer progression. Arachidonic acid activates these genes through the "PI3-kinase" pathway, which is known to play a key role in the pathogenesis of cancer. Adding a nonsteroidal anti-inflammatory drug or a PI3-kinase inhibitor to the culture media blocks the arachidonic acid-induced growth of prostate cancer cells.

Omega-6 versus omega-3 fatty acids and health effects
Studies indicate that a high intake of omega-6 fatty acids shifts the physiologic state to one that encourages blood clotting and platelet aggregation, increases in blood viscosity, spasm of blood vessels, and vasoconstriction. Omega-3 fatty acids, however, have antiinflammatory, blood thinning, antiarrhythmic, hypolipidemic, and vasodilatory (blood vessel dilating) properties.

Avoid arachidonic acid
Corn oil is known to be high in omega-6 fatty acids. Canola oil, olive oil and flax seed oil are better options.

Pathway in Mast Cells
When activated by diverse stimuli, mast cells mobilize arachidonic acid through cytosolic phospholipase A2, and rapidly generate both prostaglandin D2 and leukotriene C4, the parent molecule of the cysteinyl LTs. While initially recognized for their bronchoconstricting and vasoactive properties, these two eicosanoids are now known to serve diverse and pivotal functions in effector cell trafficking, antigen presentation, immune cell activation, matrix deposition, and fibrosis.

Prostaglandins (PGs) are products of the COX pathway of arachidonic acid metabolism. There are five primary PGs, PGD2, PGE2, PGF2, PGI2 and thromboxane A2, all of which signal through distinct seven transmembrane, G-protein coupled receptors. Some PGs may counteract the actions of others, or even the same PG may have opposing physiologic or immunologic effects, depending on the specific receptor through which it signals.

Arachidonic acid metabolism
The metabolism of arachidonic acid can be catalysed by either one of two enzyme families: the cyclooxygenases or the lipoxygenases. The lipoxygenase enzymes are classed into several subcategories including 5-, 12- and 15-lipoxygenases. The 5-lipoxygenase pathway has been the major focus of study due to the pronounced pro-inflammatory role of leukotrienes and the approval of 5-lipoxygenase inhibitors and leukotriene receptor antagonists for the clinical treatment of asthma. Although less well characterized, the 12-lipoxygenase as well as the 15-lipoxygenase pathway may also play an important role in the progression of human diseases such as cancer, psoriasis and atherosclerosis.