Eating seafood once a week, or food that contains omega-3 fatty acids, may protect against age-related memory loss.
The study found that people who ate seafood less than once a week had a steeper mental decline with age.
Dr Martha Clare Morris, who led the study, said:
“This study helps show that while cognitive abilities naturally decline as part of the normal aging process, there is something that we can do to mitigate this process.”
For the research, 915 people were followed for around 5 years.
They all came from retirement communities and public housing in Illinois and their average age was over 80.
All had memory tests and reported how much seafood they ate.
This included foods like fish cakes, tuna sandwiches, shrimp and crab.
The results showed that people who ate more seafood had better semantic memory: this is something like general knowledge.
Consuming more seafood was also linked to stronger perceptual skills.
The study was published in the journal Neurology (van de Rest et al., 2016).