A number of epidemiological studies have found that higher consumption of Docosaehexanoic acid (DHA), an omega-3 fat found in fatty fish such as salmon, albacore tuna, whitefish and seaweed, is associated with reduced risk of developing Alzheimer’s Disease. So researchers were hopeful it might also serve as a treatment for the cognitive decline characteristic of the disease among people who already have it. However, a randomized, double-blind placebo-controlled trial recently published in the Journal of the American Medical Association found that DHA supplementation did not reduce cognitive decline in those with Alzheimer’s.
The study involved 402 participants with an average age of 76 years who had mild to moderate Alzheimer’s Disease and low baseline dietary intakes of DHA. Treatment consisted of either 1g of DHA derived from algae twice daily, or a placebo twice daily. The objective was to assess and compared changes in scores on various tests that assess factors such as memory, attention, orientation, judgment, problem-solving skills, and ability to tend to personal care and activities of daily living between the experimental and placebo groups. Some participants were also given a MRI and had their cerebrospinal fluid (the fluid surrounding the brain) tested for DHA levels.
No significant differences in test scores were observed between members of the DHA experimental group and placebo groups. Even those with the mildest dementia at the start of the trial did not improve significantly with DHA supplementation.
The study concluded that DHA does not slow the decline in cognitive and functional abilities in those with pre-existing Alzheimer’s disease, and that DHA supplementation should not be considered an effective treatment option. Of course, that doesn’t mean to skip it entirely. Not only is DHA still an important part of a healthy diet, but it has also been found to be beneficial in the battle against depression.