The body needs fatty acids to survive and is able to make all but two of them: linoleic acid (LA), in the omega-6 family, and alpha-linolenic acid (ALA) in the omega-3 family. These two fatty acids must be supplied by the diet and are therefore considered essential fatty acids (EFAs).
Omega-6 fatty acids are well-supplied in the diet by meat and vegetable oils. However, not all omega-6 fatty acids are of equal value. Arachidonic acid (AA) tends to be unhealthy because it is the precursor of inflammatory eicosanoids such as prostaglandin E2 (PGE2), thromboxane A2, and leukotriene B4 which promote inflammation. In contrast, gamma-linolenic acid (GLA), found in evening primrose oil, borage oil, and black currant oil, is an important fatty acid that plays a beneficial role in healthy prostaglandin (PGE1) formation and pro-inflammatory mediator reduction.98,99
Evening primrose is a wildflower that is now grown commercially. Evening primrose oil (EPO) from Jarrow Formulas contains an omega-6 essential fatty acid, gamma-linolenic acid (GLA), which is the active ingredient and has been recommended for its fluid-regulating properties.