Researchers from the Japan Foundation for Aging and Health conducted a three-month trial of 21 patients whose average age was 68. All the patients had been diagnosed with mild cognitive impairment -- 10 from organic brain lesions and eight from early onset of Alzheimer's.
The participants were randomly assigned to one of two groups: The first took six daily capsules of DHA (docosahexaenoic acid) and ARA (arachidonic acid), along with asthaxanthin capsules, and the second group was given placebo.
The researchers tested the participants at the beginning of the trial and again after three months using repeatable battery to assess neuropsychological status (RBANS) tests.
According to the study's lead author, Susumu Kotani, the patients who took the supplements displayed improved immediate memory and attention, based on their RBANS scores. The greatest improvement was observed in immediate memory among patients diagnosed with organic brain lesions.
"It is suggested from these data that ARA and DHA supplementation can improve the cognitive dysfunction due to organic brain damages or aging," Kotani said. The study suggested that because ARA (omega-6) levels in the brain decrease with aging, replacing those fatty acids might slow mental decline.
The researchers did not observe improvements in the Alzheimer's patients or those taking the placebo, but earlier studies have shown that regular intake of omega-3 fatty acids can improve behavior and cognitive function in patients with Alzheimer's.
The researchers believe that the improvements among the brain lesion patients occurred because ARA supplementation may improve brain membrane fluidity and generation of neurons and synapses.