When I was a meat eater, I took fish oil supplements. Many people asked me why I didn’t eat fish, and even when I was a meat eater I was aware that fish is contaminated with mercury, cadmium, PCBs, microplastics, and flame retardants. Fish is not safe. However, fish oil supplement companies claimed that their products were tested for mercury, which gave me confidence. I have no idea whether fish oil supplement companies test for other waterborne contaminants such as PCBs, flame retardants, etc.
If you want omega 3 DHA and EPA in high quantities without taking supplements, you need to eat fish. The problem with eating fish is that fish is contaminated, so if you try to avoid supplements and eat fish because you somehow think that natural food is better, eating fish will actually ensure that you are supplementing your diet with mercury, dioxins, etc.
Supplements are the answer. Natural is not always better. If we lived in a world where we had clean oceans, we could rely on fish to provide DHA and EPA, but we don’t live in that world. For too many companies, it is more profitable to dump waste directly into the ocean than it is to dispose of it properly.
Now that I am vegan, I simply replace fish oil supplements with vegan DHA and EPA supplements derived from algae. I personally buy Source Naturals DHA and EPA supplements from iHerb.
When looking for omega 3 supplements, vegans should look for DHA supplements. If the supplements have both DHA and EPA in it, that’s fine, but DHA by itself is fine because EPA can be produced in the body from DHA and ALA.
Taking omega 3 in ALA form by itself (e.g. walnuts, chia seeds, and flaxseeds) may not be sufficient because ALA can be converted into EPA, but it is unclear whether the body can adequately convert ALA into DHA. There are some studies that show that ALA can be converted into DHA just fine, but there are some that show the opposite. Just to be on the safe side, it’s best to take DHA supplements.
Just because ALA may not convert to DHA efficiently, it doesn’t mean we shouldn’t forget about ALA. There is evidence that ALA has health benefits in and of itself, so my recommendation to vegans is to take an EPA DHA algae oil supplement and to also eat food that is high in ALA, such as flaxseeds, chia seeds, and walnuts.
Note that even though I take DHA EPA supplements, this is a personal preference. The only supplement that vegans absolutely must take is vitamin B12. Whether we need to take DHA and EPA is still up in the air. According to Dr Tom Sanders, a professor at the Department of Medicine in King’s College London, there is insufficient evidence to show that vegans and vegetarians should take EPA and DHA supplements.
Jack Norris RD’s Omega 3 Fatty Acid Recommendations for Vegetarians