Fish oil specifically those rich in omega-3 fatty acids have long been thought of as diet that helps protect the brain and improves cognitive abilities, but a new large clinical trial has shown that that is not the case.
According to researchers at the National Institutes of Health, omega-3 fatty acids didn’t slow down the cognitive decline in 4,000 patients. Researchers pointed out omega-3 supplements didn’t stop the cognitive decline in old people.
For the researchers the participants, 72 years old on average and 58 percent female, were 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); and Omega-3 and Lutein/zeaxanthin
Researchers measured the performance of participants’ cognitive functions at the beginning of the study so as to establish a baseline. The tests were repeated two and four years later. Included in the tests were eight parts designed to test immediate and delayed recall, attention and memory, and processing speed.
Researchers found that the cognition scores of each subgroup of participants decreased to a similar extent over time, indicating that no combination of nutritional supplements made a difference.
Though previous studies on mice have shown that DHA reduces beta-amyloid plaques in mouse model, clinical trails have shown no impact on people with mild to moderate Alzheimer’s disease.
Though the current study shown no possible cognitive benefit, researchers say that factors such as timing of nutrients, or consuming them in a certain dietary pattern, may have had an impact on the overall results. Researchers advocate more research to see if dietary patterns or taking the supplements earlier in the development of diseases like Alzheimer’s would make a difference.
The study is published in American Medical Association.