A Mediterranean-style diet packed with fish, chicken and olive oil and low on fatty dairy products and meat may lower the risk of memory problems later in life, a large US study said on Monday.
But the beneficial effects of eating a diet rich in omega-3 fatty acids do not extend to people with diabetes, according to the research published in Neurology, the medical journal of the American Academy of Neurology.
The findings, described as the largest study of its kind to date, were based on dietary information from 17,478 African-American and Caucasian people with an average age of 64.
In healthy people, those who regularly ate a Mediterranean-type diet were 19 percent less likely to develop problems in their thinking and memory skills than people who did not eat that way.
There were no major difference in cognitive decline seen between blacks and whites.
"Diet is an important modifiable activity that could help in preserving cognitive functioning in late life," said Georgios Tsivgoulis, a doctor with the University of Alabama at Birmingham and the University of Athens, Greece.
"However, it is only one of several important lifestyle activities that might play a role in late-life mental functioning.
"Exercise, avoiding obesity, not smoking cigarettes and taking medications for conditions like diabetes and hypertension are also important."
The study was funded by the National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, and by the US Department of Health and Human Services.