Fish oil fights Alzheimer's

24/03/05 Researchers with the Department of Veterans Affairs (VA) and the University of California at Los Angeles (UCLA) have found that a diet high in docosahexenoic acid, or DHA -- an omega-3 fatty acid found in relatively high concentrations in cold-water fish -- dramatically slowed the progression of Alzheimer's disease in mice. Specifically, DHA cut the harmful brain plaques that mark the disease. The results appear in the March 23 online edition of the Journal of Neuroscience.

Senior author Greg M. Cole, Ph.D., a neuroscientist at the Greater Los Angeles VA Healthcare System and UCLA, said that unlike many studies with mice, this one points to the benefits of a therapy that is easily available and already touted for other medical conditions. DHA -- either from food sources such as fish and soy, or in fish-oil supplements -- is recommended by many cardiologists for heart health, based on scores of previous studies.

A similar study by Cole's group published in Neuron last fall showed that DHA protected against damage to the "synaptic" areas where brain cells communicate and enabled mice to perform better on memory tests.

The studies, say the scientists, suggest that even people who are genetically predisposed to the disease may be able to delay it by boosting their DHA intake.

Omega-3 fatty acids, typically deficient in the American diet, are essential for human health. DHA in particular is vital to proper brain function, as well as eye health and other body processes. In recent years epidemiologists have tied fish-rich diets to a lower incidence of Alzheimer's disease and homed in on DHA as the preventive factor. Omega-3 fatty acid supplements are now being tested in clinical trials with early-stage Alzheimer's patients in the United States, Canada and Sweden to see if the therapy really slows the disease.

Food sources of omega-3 fatty acids include fish such as salmon, halibut, mackerel and sardines, as well as almonds, walnuts, soy, and DHA-enriched eggs. Concerns about mercury contamination in fish have helped popularize purified DHA supplements based on fish oil or algae.