[joveian]

As others have mentioned, there are a variety of algae based vegan EPA and DHA supplements on the market now, but most people probably don't need to worry about it. Some people do not feel good when switching to a vegan diet, and EPA/DHA supplementation might be something to try. There is a lot of vegan food in the world and two vegans can easily have completely distinct diets.

One particular supplement I like is Green Foods True Vitality, which I think is the least expensive for vegan DHA supplementation: http://www.greenfoods.com/store/p/44-True-Vitality-Vanilla.a...

It isn't bad on its own, but I mix it with my usual soy drink which is NOW Foods soy milk powder (which is just powdered soybeans; sadly the only equivalent with rice is rediculously expensive), (vegan) cane sugar (because it is much less expensive than maple syrup :( ), a dash of ground whole stevia herb (to reduce the amount of sugar needed), and a little vanilla powder. Quite delicious :).

Edit: After reading SwellJoe's excellent reply again I would also like to emphasise that many fruits and vegetables have really excellent nutritional profiles and just eating more of them can solve most nutritional issues. Even with vegan diets it is quite easy to not do that, but it is almost certianly the healthiest option.