Can an omega-3 fatty acid slow the progression of Alzheimer's disease?
Fish and Alzheimer's disease
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 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 Washington University School of Medicine and Saint Louis University School of Medicine will evaluate DHA in a clinical trial sponsored by the National Institute on Aging (NIA).
The local effort is part of a nationwide consortium of leading Alzheimer's disease researchers supported by the 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. James Galvin, M.D., M.P.H., at Washington University School of Medicine, and George Grossberg, M.D., at Saint Louis University School of Medicine, will conduct the study locally.
Researchers will primarily evaluate whether taking DHA over many months slows 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," Galvin says. "Our hope is that we may find out that DHA plays a role in slowing the 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.
"Study volunteers will be critical to helping us find out if DHA can make an impact on the disease process," Grossberg says.
For the clinical trial the Martek Biosciences Corporation of Columbia, Md., 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 of participants will receive DHA, and 40 percent will get the placebo. Doctors and nurses at the 52 research clinic sites 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 disease progression through cognitive tests, researchers will also evaluate whether taking DHA supplements has a positive effect on physical and biological markers of Alzheimer's disease, such as brain atrophy and proteins in blood and spinal fluid.