Omega-3 Fatty Acid Docosahexaenoic Acid (DHA)

Legacy Study: Closed for Enrollment

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 (AD). In order to test whether an omega-3 fatty acid can impact the progression of Alzheimer’s disease, researchers are evaluating Docosahexaenoic acid in a nationwide clinical study.

The study is taking place at 51 sites across the United States with 402 enrolled participants age 50 and older who have mild to moderate Alzheimer’s disease. Joseph Quinn, M.D., associate professor of neurology at Oregon Health and Science University, is directing the study.

Researchers are evaluating primarily whether the omega-3 fatty acid docosahexaenoic acid (DHA), taken 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 study that began screening in January 2007 and concluded enrolling participants in November 2007, investigators will measure the progress of the disease using standard tests for functional and cognitive change.

The ADCS and its consortium of researchers elected to embark on the study because in recent European studies and in 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.

The study is using DHA donated by Martek Biosciences Corporation of Columbia, MD. About two-thirds of the participants take 2 grams of DHA and the remainder takes the placebo. Doctors and nurses at the 51 research clinical sites monitor participants throughout the study during regular study visits. To ensure unbiased results, neither the researchers conducting the study nor the participants know who is getting DHA and who is getting the placebo.

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