There are 3 main forms of omega-3 in foods - EPA, DHA and ALA.
EPA and DHA are found in animal sources of omega-3 such as salmon, whereas plant sources such as flaxseeds and chia seeds tend to be high in ALA.
EPA and DHA can be used by the body, whereas ALA cannot and must be converted into the other forms. The conversion rate varies between people but is very low, typically <10% for men and <20% for women. Therefore it is recommended to include animal sources of omega-3 in the diet when possible.
The table below shows commonly available foods with the highest omega-3 content: