At the top of the list are cold water fish.
Herring, Wild salmon, Bluefin tuna, Mackerel, Sardines, and Anchovies. Two dinners a week from any of these, or a mix will give you all the O-3 you need for that week. That takes us to sardines, anchovies, caviar and oysters, all good choices for varied meals and getting the O-3 you need. It really comes down to how you eat and how you organize the foods you eat.
Here’s where Cod Liver oil pops up. Cod Liver oil is really a supplement, but is extremely rich in O-3 and loaded with vitamins A and D. If you go this route all you need is one tablespoon per day.
There are a number of fish oil and Omega-3 supplements on the market. Epa and dha will be listed on the label. Epa will always be the higher number. Epa is an inflammation fighter while DHA builds and repairs tissue. You want to avoid supplements with Omega-6 (O-6) unless told to take O-6 by your doctor.
Before you start taking any supplements talk to your doctor about what your planning on doing.
If you’re a vegetarian or vegan and don’t eat any of the things I’ve listed above, there are plant based foods that contain O-3.
Vegetables that contain O-3 are avocados and Brussel sprouts. Then you have seeds and oils. At the top of the list is flaxseed.
Flaxseed is an O-3 powerhouse that’s frequently ground into a powder so it can be used with granola and sprinkled on cereal or mixed into yogurt or a smoothy. If you’re system isn’t accustomed to flaxseed, it might be advisable to begin slowly and build. Flaxseed can clean you out in a hurry.
Chia seeds are another O-3 powerhouse. Next on the list is hemp seed.
Hemp seed is a good source of O-3 as well as protein, magnesium, iron, and zinc.
Edamame and soybeans are a good source of O-3 and are good heated or worked into a salad.
Algal oil is an oil derived from algae.
Canola oil is a good source of O-3 and is an excellent cooking oil.
Perilla oil is a good source of O-3 that’s derived from perilla seeds. It’s frequently used as a cooking oil in Korean foods and as a condiment.
Source : https://www.webmd.com/diet/foods-high-in-omega-3