Fish oil vs Flaxseed
Ground flaxseed is the cheapest reliable ALA source, but conversion to EPA and DHA is limited. The complete plant-based answer is flax for ALA plus a small daily algae-oil capsule.
Per per serving
Greenhouse gaseskg CO₂e / kg
Fish oil
6
Flaxseed
1.2
ALAg / serving
Fish oil
0
Flaxseed
6.5
Direct EPA/DHAmg / serving
Fish oil
1000
Flaxseed
0
Contaminant loadrelative
Fish oil
1
Flaxseed
0
Source: Poore & Nemecek (2018), Science · Our World in Data · USDA FoodData Central
Verdict
Flax covers ALA; pair it with algae oil to cover EPA and DHA directly.
Questions people ask
Must flax be ground?
Yes. Whole seeds pass through undigested; grind them or buy milled and keep it refrigerated.