Most experts agree that the best way to get omega-3 fatty acids is by eating fatty fish, which contain the highest amounts of EPA and DHA. These fish include salmon, mackerel, and trout. Fish oil supplements are not thought to be as beneficial.
“Whole fish provides additional nutrients and bioavailability advantages over supplements,” says Avena.
Dr. Yassine notes that, overall, fish oil supplementation trials have been inconclusive. “Fish is complex. Even the actual DHA and EPA in fish is not the same as what is present in supplements,” he says
For people who don’t eat fish, Avena says algal oil is the best plant-based source of DHA and EPA, as it’s derived from the same marine algae that fish consume.
Flaxseeds, chia seeds, hemp seeds, and walnuts contain alpha-linolenic acid (ALA) which can be converted into EPA and then to DHA in the body, but not very efficiently, which is why consuming marine food sources is preferable.
How Much Fish Oil Should I Take?
The 2020–2025 Dietary Guidelines for Americans recommend that adults eat 8 ounces (oz) of fish per week. The average size of a main portion fish filet is around 8 oz when raw and 6 oz when cooked (use the size of your hand as guide to portion size), so it’s best to aim for at least one serving a week or more. But even if you’re only getting one serving of fish per week, the brain may benefit.
“Research shows that when comparing people who are consuming one or more servings of fish per week to those who are eating less, fish eaters experience less cognitive decline over the years,” Dr. Agarwal says.
“That should be encouraging, because this is a simple lifestyle modification to maintain brain health,” Agarwal says.
For those who prefer supplements, Rizzo says most fish oil supplements are 1,000 milligrams (mg). There are no universal recommendations for omega-3 supplements, but the U.S. Food and Drug Administration specifies that the labels of dietary supplements should not recommend a daily intake of EPA and DHA higher than 2 grams (g).
At high doses, fish oil supplements may act as a blood thinner, increasing the risk of bleeding in people who take anticoagulant or antiplatelet drugs, as well as any herbs or other supplements that reduce blood clotting.
