Omega-3 Fatty Acids in Fish May Provide Brain Benefits

Sonya Collins

Updated November 15, 2024

A close-up view of salmon, beans, avocado, olive oil, spinach, broccoli and mixed nuts

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People who eat a lot of seafood, particularly so-called “fatty” fish, may be at lower risk for the loss of thinking skills that can be a result of Alzheimer’s disease. That’s why, in 2018, AARP’s Global Council on Brain Health put fish on its list of encouraged foods and recommended that people eat at least one serving of non-fried fish per week for better brain health.

“Most studies show that the equivalent of a Mediterranean diet may prevent cognitive decline,” says geriatrician and neuroscientist Howard Fillit, M.D., a member of the GCBH and co-founder and chief science officer of the Alzheimer’s Drug Discovery Foundation. “Fruits and vegetables are important, as are oily fish, like salmon, that provide omega-3 fatty acids.”

Researchers speculate that it’s the omega-3s found in fish oil that serve up the brain benefits, but they don’t know for sure.

What are omega-3 fatty acids? They’re called “essential” because you have to get them from the food you eat, according to the National Institutes of Health. They’re in salmon and mackerel; nuts and seeds; plant-derived oils like canola; and certain processed foods that are enriched with the nutrient.

In your body, omega-3s are an important part of the membrane around the exterior of every cell in your body. They give your body energy and also have roles to play in your heart, blood vessels, lungs, immune system and the glands that produce hormones. There are three main types of omega-3s: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA, for example, is found in large quantities in the eyes and the brain.

Given DHA’s presence in the brain as well as the possible role of seafood in brain health, researchers have tried to determine whether omega-3 supplements might improve or protect brain health. Older adults sure seem to think so. According to a 2021 survey by AARP, among those who take supplements for brain health benefits, nearly six in 10 of them reach for omega-3s.

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But a role for these supplements in brain health isn’t strongly supported by research.

The GCBH, an independent collaborative of scientists, health care providers and other experts, evaluated evidence on the subject in its report, and concluded, “the weight of existing evidence does not sufficiently demonstrate benefit [of supplements].… If you can’t or don’t eat fish, ask your health care provider about whether you should take a supplement containing DHA and EPA.

A few small studies have found that DHA supplements may help people who have mild cognitive impairment, which can, but does not always, lead to dementia. Some research also shows that people who have low levels of DHA might benefit from supplements. But low DHA is extremely rare in the United States. Research that includes people with a rare omega-3 deficiency doesn’t necessarily apply to the population at large.

In a 2023 review in the journal CNS Drugs, researchers analyzed existing research on the brain benefits of some 18 ingredients commonly found in supplements sold as memory products. Like the GCBH, the researchers concluded that there isn’t enough evidence to support recommending omega-3 supplements for memory.