Consuming a diet rich in the omega-3 fatty acid docosahexanoic acid (DHA) may help prevent or treat Alzheimer’s disease, findings from an animal study suggest.

In the study, which is reported in The Journal of Neuroscience, mice that ate DHA-enriched chow showed less beta-amyloid build-up in the brain than mice fed regular chow. Beta-amyloid is a protein that forms the characteristic brain plaques seen in patients with Alzheimer’s disease.

“These results suggest that dietary DHA could be protective against beta-amyloid production, accumulation, and potential downstream toxicity,” senior author Dr. Greg M. Cole, from the University of California at Los Angeles, and colleagues note.

Research has linked high levels of DHA in the diet with a reduced risk of Alzheimer’s disease. Still, the studies have shown an association, but don’t prove that eating a diet high in DHA actually reduces amyloid levels and prevents Alzheimer’s disease. To show this, animal studies are often needed.

Cole’s team used a mouse model of Alzheimer’s disease and fed the animals low- or high-DHA chow or regular chow. The animals were fed the assigned diet until 22.5 months of age, at which point brain tissue was obtained and tested for amyloid build-up.

The high-DHA diet reduced total amyloid level by 70 percent compared with the other diets, the investigators report. Moreover, brain plaques were reduced by 40.3 percent.

Several studies are currently underway to determine if fatty acids like DHA offer any benefits for patients with mild-to-moderate Alzheimer’s disease, the authors add.

SOURCE: The Journal of Neuroscience, March 30, 2005.