long chain omega 3 fatty acids, as found in fatty fish, are important for our health - this much is clear. But from this, one cannot conclude that everybody should eat more fish.
In fact they are so important that human evolution has adapted our metabolism to the availability or lack of the fish oil compounds. Thus people from a fish-eating genetic heritage may need the fish oils, while others from a long vegetarian tradition have evolved their own ways of producing the compounds in their body.
Thus, the answer is complicated, as I have explained in my latest feature which is out now in Current Biology:
How our diet changed our evolution
Current Biology Volume 27, Issue 15, 7 August 2017, Pages R731–R733
FREE access to full text and PDF download
In Inuit and other populations traditionally relying on seafood, researchers have found gene variants that weaken the endogenous synthesis of the fatty acids that these people take up with their regular doses of fish. (Photo: Louise Murray/Science Photo Library.)