What to eat to reduce your risk of Alzheimer’s disease

Would you like reduce your risk of cognitive impairment, Alzheimer’s disease, and dementia? Researchers from around the world having been studying a variety of different factors that might reduce these risks and keep the brain healthy.

Old news: The Mediterranean diet is beneficial

One factor that a number of studies have converged on is a Mediterranean-style diet. This diet includes

  • fish
  • olive oil
  • avocados
  • fruits
  • vegetables
  • nuts
  • beans
  • whole grains
  • red wine in moderation.

Now, if you’re like me and you happen to like all these foods, then you have all the information you need to eat a brain-healthy diet. On the other hand, if you’re not crazy about everything on the list, perhaps you would rather eat just the most important components. Researchers have, in fact, been trying to determine the key parts of this diet for a number of years.

For example, one study published in 2015 and updated in 2018 compared healthy older adults who followed a Mediterranean diet with extra olive oil or extra nuts versus a control reduced-fat diet. The enhanced Mediterranean diet groups fared equally well, and both had better cognitive performance outcomes than the reduced-fat diet group. No study, however, has been able to determine the critical components of the Mediterranean diet that makes it so good for your brain — until now.

The new study

Researchers at the National Institutes of Health recently published a study that evaluated the lifestyles of over 7,750 participants followed for five to 10 years. Participants filled out questionnaires to determine their eating habits, and had cognitive tests of memory, language, and attention administered over the phone. They used these data to determine the dietary factors most important in lowering your risk of cognitive impairment, as well as the dietary factors most important in lowering your risk of cognitive decline.

Cognitive impairment versus cognitive decline

Let’s take a moment to unpack these terms. Let’s say you want to know what your risk is 10 years from now.

  • Cognition is a shorthand way of saying thinking, memory, language, attention, visuospatial, and other mental abilities.
  • Your risk of cognitive impairment is the risk that 10 years from now, your cognition will be worse than your peers.
  • Your risk of cognitive decline is the risk that 10 years from now, your cognition will be worse than it is now.

Fish helps you think — and keeps your thinking strong

What did the researchers find? Fish was the single most important dietary factor in lowering the risk of cognitive impairment. Vegetables were second best, and all other foods showed smaller, insignificant effects. Moreover, of all the foods evaluated, only fish was associated with a lower risk of cognitive decline. Eating fish lowered the risk of both cognitive impairment and cognitive decline.

The take-home lesson

To reduce your risk of cognitive impairment and decline, eat a Mediterranean-style diet including fish several times per week. There are lots of good fish to eat, including Atlantic mackerel, black sea bass, catfish, clams, cod, crab, crawfish, flounder, haddock, lobster, salmon, sardines, scallops, shrimp, skate, sole, squid, tilapia, trout, and canned light tuna. Just be careful about fish that may have high levels of mercury, such as swordfish and bigeye tuna; these fish should only be eaten occasionally. The FDA has a good guide to help you know the best fish to eat.

Your mother was right

Did your mother ever tell you that fish was good for you? Mine did. In fact, she always used to say, “Fish helps you think.” She knew it all along; it just took the scientific community 50 years to catch up to her and prove it.

Related Information: A Guide to Cognitive Fitness


  1. Soma Carr

    I believe it’s too risky to eat fish anymore due to heavy metals and the pollution in the ocean. I think we should let the fish repopulate and hopefully heal from efforts we can make to clean up the oceans. In the meantime what do we eat instead of fish to help us stay healthy? Lots of people have asked this question. A lot of us eat plant based now. I love fish but don’t trust ratting it now if only occasionally.

  2. Hilary

    What is it about fish? Since our oceans are becoming over-fished and there are many metals and other toxins in much of our fish stock, aren’t we better off taking omega oils made from algae, which is how those fish get the healthy tissue for us to eat in the first place?

  3. Marian Roman

    Harold, your diet and your sense of humor are a great combo for longevity .. as are genes, environment and luck.

  4. James H. Willis, MD

    Yes, we should all eat bountiful quantities of fish. Where are all these fish to come from? We inhabit a planet where excess extraction and severe environmental blight are currently crushing life in the oceans. 96% of bluefin tuna are gone! We are to blame. So the answer lies not with extracting and consuming more fish, but in a massive change in international fishery laws, environmental regulations, (plastic, especially, and coal burning, which spews mercury), and sharp attention to the climate crisis (coral reefs are massively dying). Let’s get to work.

  5. Malik Abdul Hameed

    Good article, specialy the importance of fish in diet

  6. Maree Randall

    I think one important aspect you missed is daily exercise
    That is exercising to a point where your breathing is laboured
    I feel this is the most important thing one can do for sharp brain function

    • Jacquelyn Michelson

      The sad thing is that exercise is not a guarantee to not get the disease. I had a friend who was an avid runner and got early onset Alzheimer’s at 57. His heart was in amazing health as was his body. You can do your best but it does not always work. I feel stress is a huge contributor to getting this disease.

  7. Louie Ven

    In general, fish is far more expensive in Canadian groceries than meat. It makes eating fish an expensive habit. That said, I would like to know how frozen fish (which is all we can get) compares to fresh fish on the east coast (plentiful for those who live along the coast).

  8. Mike Manzo

    I am mostly a vegetarian and is there a good alternative to fish.
    Thank you

  9. Amber Hussein

    Many thanks to send me to this usfull news.

    Dr. Amber Hussein Obeid

  10. Myrthe

    I’ve also read a study that Vitamin D is important for lowering the chances of dementia. That would make sense since it’s in fatty fish, and some of the other foods mentioned here. Your mother sounds like a smart women. Mine always used to tell us we should eat fish twice a week.

  11. P John Anderson - ( P John A. please)

    “Fish is Brain Food” – I grew up in New Zealand!

  12. Harold Melnick

    My motto has always been: “Eat everything, some of it will be good for you.” I’m 90; so far, so good.

  13. Dave

    Yep. This surely aligns with traditional wisdom. I grew up hearing from multiple generations of ancestors that “Fish is brain food!”

  14. Nadia

    If one is allergic to ALL fish and shellfish, what is the substitute that could offer the same benefits?

  15. Jesús Ramírez

    Harvard Medical School,
    What is the alternative to fish for people with a plant based diet?

  16. Hafsa Ghoul

    Very good article

  17. AJ Jordan

    This is a great article I can share with my older clients!

  18. Dr.Henry

    “To reduce your risk of cognitive impairment and decline, eat a Mediterranean-style diet” I am not sure that you can interpolate into “Mediterranean -style diet” conclusion from the new study.

    Fish rich diet or Seafood rich diet is more appropriate.

    • DRDON


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