DHA Doesn't Show Benefit in Alzheimer's Disease
Supplement not associated with slower cognitive, functional decline in mild to moderate disease
TUESDAY, Nov. 2 (HealthDay News) -- In individuals with mild to moderate Alzheimer's disease, docosahexaenoic acid (DHA) supplementation doesn't appear to slow the rate of cognitive and functional decline, according to research published in the Nov. 3 issue of the Journal of the American Medical Association.
Joseph F. Quinn, M.D., of the Oregon Health and Science University in Portland, and colleagues analyzed data from 402 patients with mild to moderate Alzheimer's who were randomized to receive 2 g of algal DHA or placebo daily for 18 months. Of this group, 295 completed the trial while taking study medication. Outcomes included change in the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog) and the Clinical Dementia Rating (CDR) sum of boxes.
The researchers found that DHA supplementation didn't show a benefit for rate of change on the ADAS-cog score, and wasn't associated with a difference in CDR sum of boxes score. Among a subgroup that underwent magnetic resonance imaging at baseline and 18 months, DHA treatment didn't affect the rate of brain atrophy.
"Effective treatment strategies to prevent progression of Alzheimer's disease will likely need to be initiated earlier in the course of [the disease] in order to be more efficacious. Given the accumulating evidence that the pathophysiological process of Alzheimer's disease begins years, if not decades, prior to the diagnosis of clinical dementia, treatment of mild to moderate Alzheimer's disease may be 'too late,'" writes the author of an accompanying editorial.
Several co-authors disclosed both involvement with a patent related to this issue and relationships with Martek Biosciences, which provided the drug and placebo and other support for the study. The editorial author disclosed relationships with several pharmaceutical companies.