Can an Omega-3 Fatty Acid Slow the Progression of Alzheimer's Disease? Local NIH-Supported Researchers Participate in Nationwide Trial

March 28, 2007

Nutritionists have long endorsed fish as part of a heart-healthy diet, and now some studies suggest that omega-3 fatty acids found in the oil of certain fish, algae and human breast milk may also benefit the brain by lowering the risk of Alzheimer’s disease. In order to test whether docosahexaenoic acid (DHA), an omega-3 fatty acid, can impact the progression of Alzheimer’s disease, researchers at the USC Keck School of Medicine supported by the National Institute on Aging (NIA), part of the National Institutes of Health, will test DHA in a clinical trial.

The local effort is part of a nationwide consortium of leading Alzheimer’s disease researchers supported by NIA and coordinated by the University of California, San Diego. The trial will take place at 52 sites across the United States. It seeks 400 participants age 50 and older with mild to moderate Alzheimer’s disease. Joseph Quinn, M.D., associate professor of neurology at Oregon Health and Science University, is directing the national study. Lon S. Schneider, M.D., professor of psychiatry, neurology and gerontology at the Keck School of Medicine of the University of Southern California (USC) will conduct the study locally.

Researchers will primarily evaluate whether taking DHA over many months slows the progression of both cognitive and functional decline in people with mild to moderate Alzheimer’s. During the 18-month clinical trial, investigators will measure the progress of the disease using standard tests for functional and cognitive change.

“Evidence to date in various research studies that have examined the effect of omega-3 fatty acids on Alzheimer’s disease merits further evaluation in a rigorous clinical trial,” says Schneider, who is also the director of the USC Alzheimer’s Disease Research Center of California. “Our hope is that we may find out that DHA plays a role in slowing the clinical progression of this destructive disease.”

In recent European studies and the Framingham Heart Study, scientists reported that people with the highest blood levels of DHA were about half as likely to develop dementia as those with lower levels.

“Volunteers will be critical to helping us find out if DHA can make an impact on the disease process,” says Helena C. Chui, M.D., Director of USC’s NIA Alzheimer’s Disease Research Center.

For the trial the Martek Biosciences Corporation will donate a pure form of DHA made from algae devoid of fish-related contaminants. Participants will receive either two grams of DHA per day or an inactive placebo pill. About 60 percent will receive DHA and 40 percent will get the placebo. Doctors and nurses will monitor the participants in regular visits throughout the trial. To ensure unbiased results, neither the researchers conducting the trial nor the participants will know who is getting DHA and who is receiving the placebo.

In addition to monitoring clinical progression through cognitive tests, researchers will evaluate whether taking DHA has a positive effect on physical and biological markers of Alzheimer’s such as brain atrophy and proteins in blood and spinal fluid.