While some research suggests that a diet high in omega-3 fatty acids can protect brain health, a study published in the Journal of the American Medical Association shows that omega-3 supplements did not slow cognitive decline in older persons. With 4,000 patients followed over a five-year period, the National Institutes of Health (NIH) study is one of the largest and longest of its kind.
All participants had early or intermediate age-related macular degeneration (AMD). They were 72 years old on average and 58% were female. They were randomly assigned to one of the following groups: placebo (an inert pill); omega-3 [specifically docosahexaenoic acid (DHA, 350 mg) and eicosapentaenoic acid (650 mg)]; lutein and zeaxanthin (nutrients found in large amounts in green leafy vegetables); omega-3 and lutein/zeaxanthin.
Participants were given cognitive function tests at the beginning of the study to establish a baseline, then at two and four years later. The tests, all validated and used in previous cognitive function studies, included eight parts designed to test immediate and delayed recall, attention and memory, and processing speed. The cognition scores of each subgroup decreased to a similar extent over time, indicating that no combination of nutritional supplements made a difference.
“Contrary to popular belief, we didn’t see any benefit of omega-3 supplements for stopping cognitive decline,” said Emily Chew, deputy director of the Division of Epidemiology and Clinical Applications and deputy clinical director at the National Eye Institute (NEI), part of NIH.
