>- polyunsaturated fats are the category that includes omega 6 and omega 3 fatty acids. Even further, omega 3's can be ALA (from plants) or DHA (e.g. salmon) variety. Omega 3's and in particular DHA have been shown to have anti-inflammatory and other health properties.
You missed EPA which is also in fatty fish. ALA doesn't convert very well in humans to DHA or EPA. So eating lots of flax to get Omega3 is pretty useless.
Opinion: The conclusion I came to a few years ago is that we have too much PUFA in our foods, of which Omega-6 is just one form. Eating fatty fish and cutting down on vegetable oils high in O6 help to restore a more natural ratio that humans are more tolerant to. But ultimately saturated fats are intended to be the primary fuel.