Consuming more omega-3 fatty acids -- found in many types of fish -- may benefit people at risk for Alzheimer's disease, a new study suggests.
Researchers looked at 40 mentally healthy adults, aged 65 to 75, who had the gene variant APOE e4, which put them at risk for late-onset Alzheimer's.
Those who consumed higher amounts of two omega-3 fatty acids found in fish -- DHA and EPA -- did better on tests that assessed their ability to switch between mental tasks -- called cognitive flexibility. They also had a larger anterior cingulate cortex, a part of the brain involved in mental flexibility, the researchers said.
The findings suggest -- but do not prove -- that consuming DHA and EPA omega-3 fatty acids might improve mental flexibility by boosting the size of the anterior cingulate cortex, said the authors of the study published online May 21 in the journal Frontiers in Aging Neuroscience.
Funding for the study was provided by Abbott Nutrition, a division of Abbott, a maker of health-care products.
"Recent research suggests that there is a critical link between nutritional deficiencies and the incidence of both cognitive [mental] impairment and degenerative neurological disorders, such as Alzheimer's disease," said study co-leader Aron Barbey, a professor of neuroscience, psychology, and speech and hearing science at the University of Illinois.
"Our findings add to the evidence that optimal nutrition helps preserve cognitive function, slow the progression of aging and reduce the incidence of debilitating diseases in healthy aging populations," Barbey added in a university news release.
However, the study does not show that consuming DHA and EPA could actually prevent Alzheimer's, the most common form of dementia.
The study focused on areas of brain function sometimes overlooked in research on aging, said study co-leader Marta Zamroziewicz, a medical/doctoral student.
"A lot of work in cognitive aging focuses on memory, but in fact cognitive flexibility and other executive functions have been shown to better predict daily functioning than memory does," Zamroziewicz said in the news release.
Executive function refers to skills such as reasoning, planning, problem solving, paying attention, impulse control and task switching.
"These functions tend to decline earlier than other cognitive functions in aging," Zamroziewicz said.