Considering how good fish oil is for the brain, you would think fish would be a lot smarter. Good fish oil is comprised of Omega-3 fatty acids. These are what we call essential fatty acids because the body cannot produce enough for its own needs so we have to either eat foods containing them or supplement.
There are 4 Omega-3s that we need EPA, DHA, DPA and ALA. They have very long names. EPA has gotten a lot of attention because it is very good at reducing systemic inflammation and cardiovascular health. Most of the supplements you find on the shelf of health food stores will be either all EPA or a blend of EPA, DHA, and maybe ALA.