While omega 6 is beneficial to one's diet, there is an overabundance of it in the typical western diet. The human body needs a proper omega 6 to omega 3 ratio to best work with the ECS for optimal health.
84% of Omega fatty acids consumed in the USA are in the form of an omega 6 called linoleic acid (LA), the precursor to AEA (anandamide). AEA is an endocannabinoid that plays an important role in the regulation of appetite, pleasure, and reward. AEA makes people less anxious and more able to forget fearful and unpleasant experiences.
However, too high of an omega 6 LA intake through diet promotes obesity in both animals and humans and is correlated with increased fasting blood glucose, fasting insulin, and insulin resistance in humans.
A recent study found that substituting fish oil with soy oil in salmon feed increased AA (arachidonic acid), AEA, and 2-AG (endocannabinoids) and decreased DHA and EPA (Omega 3s) in the salmon. These same fish were then fed to mice which resulted in an increased liver content of omega 6 LA, AA, AEA, and 2-AG and decreased omega 3 DHA and EPA, accompanied by weight gain and adipose tissue inflammation when compared to the control fed animals.
Soy is higher in omega 6 LA in ratio to its omega 3 ALA at around 7.5 to 1. So the omega 6 to omega 3 ratio is two to three times higher than it should be for most people if we are trying to maintain closer to a three to one omega 6 to omega 3 ratio.
Omega 3 EPA competes with omega 6 AA for the enzyme phospholipase A2 necessary to release AA from the membrane phospholipids (where it is stored). AA is the preferred molecule to be broken down by the enzyme.
Based on this, one should strive for a better balance of omega 3 and 6 in their diet. There are different omega 6 and 3 and not all are the same. However, in general, that balance is something to strive for in your diet. The key being EPA and DHA for their beneficial properties.
Think about the increase in all manner of inflammatory related disease. Now look at the increase of omega 6 heavy oils over the last century in the US.
Soy is not all bad for you, however, you must eat it correctly. Soy is best eaten fermented, such as Miso, Tamari, and Tempeh. There are more fermented soy foods that have a history of being beneficial for health, but the key is the fermentation.