February 29/Los Angeles/UCLA -- A diet high in fish has been reported to reduce the risk of cardiovascular disease and loss of cognitive function (thinking ability and memory). A new study reported by UCLA researchers has added to the evidence that eating fish can preserve mental function. It noted that a diet deficient in omega-3 fatty acids, which are commonly found in fish, may cause increased brain aging and decrease in cognitive function. The investigators noted that their study demonstrated that individuals with lower levels of omega-3 fatty acids had lower brain volumes; the decrease was equivalent to two years of structural brain aging. The study was published in the February 28 print edition of the journal Neurology, the medical journal of the American Academy of Neurology.

The study group was comprised of 1,575 subjects (average age 67) who did not suffer from dementia. They underwent magnetic resonance imaging (MRI) brain scans and were given tests to evaluate mental function and omega-3 fatty acid levels in their red blood cells. Their body mass index (BMI) was also calculated. Omega-3 fatty acids include the nutrients docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The investigators reported that individuals whose DHA levels were in the bottom 25% had lower brain volumes than those with higher DHA levels. Furthermore, individuals whose levels of all omega-3 fatty acids were in the bottom 25% scored lower on tests of visual memory and executive function, including problem-solving, multi-tasking, and abstract thinking.

The researchers noted that previous studies have reported that eating fatty fish reduces the risk of dementia; however, others studies have failed to confirm a protective association between a fish diet and maintenance of cognitive function. They noted that their study, which focused on middle-aged to elderly subjects who had no evidence of either a stroke or dementia, supported the association.

The study was supported by the National Heart, Lung, and Blood Institute's Framingham Heart Study and the National Institute on Aging.

From the March 1, 2012, Prepared Foods' Daily News.