Researchers reporting in tomorrow's issue of Neurology have found that older adults whose diets include three or more weekly helpings of baked or broiled tuna and other fish high in omega-3 fatty acids are less likely to develop "silent" brain lesions that can lead to cognitive decline and vascular stroke.
A brain lesion, or infarct, is an area of damaged brain tissue. The damage typically results from a lack of blood flow to the area. The lesion is dubbed "silent" if it developed in someone who has not had a recognized stroke or transient ischemic attack (TIA), also called a mini-stroke. Silent brain lesions are very common, especially as a person grows older. The lesions can cause thinking problems, memory loss, and stroke.
"Previous findings have shown that fish and fish oil can help prevent stroke, but this is one of the only studies that looks at fish's effect on silent brain infarcts in healthy, older people," Jyrki Virtanen, PhD, RD, with the University of Kuopio in Finland, says in a news release.
For the study, Virtanen and colleagues looked at magnetic resonance imaging (MRI) brain scans of 3,600 adults aged 65 and older who had no history of cerebrovascular disease. Five years later, researchers rescanned 2,313 individuals who had agreed to the follow-up and asked them questions about their diets, including how much fish they ate.
After comparing scans and analyzing diet information, the team learned that the adults who ate non-fried tuna and other fish high in omega-3 fatty acids at least three times a week had a nearly 26% lower risk of silent brain lesions than those who opted for such foods less often.
Eating just one serving of fish per week also had a protective benefit. Adults in this category reduced their risk of silent brain lesions by 13%.
Those who regularly chose the healthy fish also had fewer changes in the white matter in their brains.
"While eating tuna and other types of fish seems to help protect against memory loss and stroke, these results were not found in people who regularly ate fried fish," Virtanen says. "More research is needed as to why these types of fish may have protective effects, but the omega-3 fatty acids EPA and DHA would seem to have a major role."
In addition to tuna, salmon, mackerel, herring, sardines, and anchovies are all rich in omega-3 fatty acids.
By Kelli Stacy
Reviewed by Elizabeth Klodas
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