Foods high in omega-3, ranked by EPA+DHA per serving

Salmon (~1.5-2 g), sardines (~1.4 g), and mackerel (~2.5 g) per 100 g lead on EPA+DHA. The per-serving ranking, why plant ALA does not count the same, and when food beats a capsule.

1. 01

   Atlantic mackerel: ~2.5 g EPA+DHA per 100 g

   The single densest common source: ~2.5 g of EPA+DHA per 100 g cooked (USDA), roughly 5x a full day's general-health target in one serving. Low mercury as Atlantic/Pacific mackerel (~0.05 ppm, FDA), unlike high-mercury king mackerel. One serving a week alone can average out the 250-500 mg/day goal. The constraint is taste and availability, not omega-3 yield.

2. 02

   Salmon (farmed or wild): ~1.5-2 g EPA+DHA per 100 g

   A 100 g portion supplies ~1,500-2,000 mg EPA+DHA (USDA), with farmed running slightly higher than wild on total fat. Very low mercury (~0.022 ppm, FDA), so it is the default omega-3 fish. Two servings a week averages ~430-570 mg/day, clearing the target from food alone. Canned wild salmon adds edible bones for calcium and is the cheapest reliable route per gram of omega-3.

3. 03

   Herring: ~1.7 g EPA+DHA per 100 g

   ~1.7 g EPA+DHA per 100 g (USDA), low on the food chain and low mercury. Sold pickled, smoked, or canned, it is a shelf-stable, inexpensive oily fish that is underused in the US. One 100 g serving covers several days of the general-health target. Watch added sodium in pickled and smoked versions, which is a bigger practical concern here than mercury.

4. 04

   Sardines: ~1.4 g EPA+DHA per 100 g

   ~1.4 g EPA+DHA per 100 g (USDA), among the lowest mercury of any fish (~0.013 ppm, FDA) because they are short-lived and low on the food chain. Canned in water or olive oil, shelf-stable, and among the cheapest EPA+DHA sources per gram. Edible bones add calcium. The best cost-per-omega-3 option on the list for anyone who tolerates the flavor.

5. 05

   Oysters and mussels: ~0.4-0.7 g EPA+DHA per 100 g

   Shellfish are a moderate but real source: mussels ~0.7 g and oysters ~0.4 g EPA+DHA per 100 g (USDA), alongside zinc and B12. Lower per serving than oily fish, so they are a supporting source rather than a base. Useful for variety and for people who prefer shellfish; two servings will not hit the target the way salmon or mackerel do, so pair them with a true oily fish.

6. 06

   Canned light tuna: ~0.27 g EPA+DHA per 100 g

   Far lower than the oily fish above at ~0.27 g EPA+DHA per 100 g (USDA), but cheap, shelf-stable, and low mercury as skipjack (~0.13 ppm, FDA). It takes roughly 4-5 servings to match the omega-3 of one salmon serving, so treat it as a protein source with a modest omega-3 bonus, not a primary EPA+DHA vehicle. Skipjack (light) runs ~3x lower mercury than albacore (white).

7. 07

   Flax, chia, walnuts (ALA): high on paper, ~5-10% usable

   This is the list's key caveat. Flax (~2.3 g ALA/tbsp), chia (~5 g ALA/oz), and walnuts (~2.5 g ALA/oz) look omega-3-rich, but they supply ALA, not EPA+DHA, and the body converts ALA at only ~5-10% (NIH ODS). So a tablespoon of flax nets only a few hundred mg of usable EPA+DHA. They are worthwhile foods and the plant route to some conversion, but they do not replace fish for the active forms. Vegans should use algae oil for preformed EPA+DHA.

8. 08

   When food beats a capsule (and when it does not)

   If you eat oily fish about twice a week, you clear the 250-500 mg/day target and a supplement adds little; whole fish also brings protein, selenium, and vitamin D. Supplement when fish intake is low, when a clinician has set a high therapeutic dose for triglycerides, or when mercury from larger fish is a concern and a tested, distilled oil is preferred. Compare a can of salmon against a capsule on $/mg of EPA+DHA in best-fish-oil, and set the number in how-much-omega-3-per-day.