An Oregon Health & Science University neurologist is directing a national study examining whether omega-3 fatty acids, found in fish, can lower the risk of Alzheimer's disease.

Joseph Quinn, M.D., associate professor of neurology, OHSU School of Medicine and the Portland Veterans Affairs Medical Center, is leading the multicenter, National Institute on Aging-funded trial testing whether docosahexaenoic acid (DHA), an omega-3 fatty acid, can impact the progression of Alzheimer's disease.

Nutritionists have long encouraged the consumption of fish as part of a heart-healthy diet. Some studies now suggest that omega-3 fatty acids found in the oil of certain fish, such as salmon, as well as algae and human breast milk may also benefit the brain by lowering the risk of Alzheimer's 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.

Quinn, an investigator at OHSU's Layton Aging & Alzheimer's Disease Center who studies potential therapies for the neurological disorder, is working with colleagues around the country to evaluate DHA in a randomized, double-blind study in which participants will receive either the DHA or a placebo.

The OHSU 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.

"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," Quinn said. "Our hope is that we may find out that DHA plays a role in slowing the progression of this destructive disease."

Researchers will primarily evaluate whether taking DHA over many months slows the progression of both cognitive (thinking) and functional decline in people with mild to moderate Alzheimer's. During the 18-month experiment, investigators will measure the progress of the disease using standard tests for cognitive change and ability to carry out daily living activities, such as managing finances, cooking and dressing. 

"Study volunteers will be critical to helping us find out if DHA can make an impact on the disease process," Quinn said.

Martek Biosciences Corp. of Columbia, Md., is donating a pure form of DHA made from algae devoid of fish-related contaminants, for the trial. 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 evaluate 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.

To learn how to participate in the study, contact Briana Studer at 503 494-9399, the NIA's Alzheimer's Disease Education and Referral Center at 800 438-4380, or by email to adear@nia.nih.gov.

The NIA leads the federal effort that supports and conducts research on aging and the medical, social and behavioral issues of older people, including Alzheimer's disease and age-related cognitive decline. For more information, visit the NIA's Alzheimer's Disease Education and Referral Center at www.nia.nih.gov/alzheimers. For general information on research and aging, go to www.nia.nih.gov and for information about NIH and its programs, visit www.nih.gov.