January 2, 2008
University of California - Los Angeles
It's good news that we are living longer, but bad news that the longer we live, the better our odds of developing late-onset Alzheimer's disease.
Many Alzheimer's researchers have long touted fish oil, by pill or diet, as an accessible and inexpensive "weapon" that may delay or prevent this debilitating disease. Now, UCLA scientists have confirmed that fish oil is indeed a deterrent against Alzheimer's, and they have identified the reasons why.
Greg Cole, professor of medicine and neurology at the David Geffen School of Medicine at UCLA and associate director of UCLA's Alzheimer Disease Research Center, and his colleagues report that the omega-3 fatty acid docosahexaenoic acid (DHA) found in fish oil increases the production of LR11, a protein that is found at reduced levels in Alzheimer's patients and which is known to destroy the protein that forms the "plaques" associated with the disease.
The plaques are deposits of a protein called beta amyloid that is thought to be toxic to neurons in the brain, leading to Alzheimer's. Since having high levels of LR11 prevents the toxic plaques from being made, low levels in patients are believed to be a factor in causing the disease.
Alzheimer's is a debilitating neurodegenerative disease that causes memory loss, dementia, personality change and ultimately death. The national Alzheimer's Association estimates that 5.1 million Americans are currently afflicted with the disease and predicts that the number may increase to between 11 million and 16 million people by the year 2050.
The researchers examined the effects of fish oil, or its component DHA, in multiple biological systems and administered the oil or fatty acid by diet and by adding it directly to neurons grown in the laboratory.
"We found that even low doses of DHA increased the levels of LR11 in rat neurons, while dietary DHA increased LR11 in brains of rats or older mice that had been genetically altered to develop Alzheimer's disease," said Cole, who is also associate director of the Geriatric Research Center at the Veterans Affairs Medical Center.
To show that the benefits of DHA were not limited to nonhuman animal cells, the researchers also confirmed a direct impact of DHA on human neuronal cells in culture as well. Thus, high levels of DHA leading to abundant LR11 seem to protect against Alzheimer's, Cole said, while low LR11 levels lead to formation of the amyloid plaques.
