Scientists at the University of California - Los Angeles (UCLA) have made advancement in the fight against Alzheimer's, by identifying the reasons why fish oil is a deterrent against the disease.
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, have confirmed that fish oil, containing omega-3 fatty acids, can prevent the debilitating disease.
Researchers reported 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' linked to 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.
For the study, 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 mice 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," Cole said.
In order to show that DHA benefits were not limited to nonhuman animal cells, the researchers also confirmed a direct impact of DHA on human neuronal cells in culture as well.
The findings therefore confirmed that high levels of DHA leading to abundant LR11 protect against Alzheimer's, while low LR11 levels lead to formation of the amyloid plaques.
As a result of the study, the National Institutes of Health (NIH) is presently conducting a large-scale clinical trial with DHA in patients with established Alzheimer's disease.
Cole said that for those patients, it might be too late in the disease's progression for DHA to have much effect.
However, he is hopeful that the NIH will conduct a large-scale prevention clinical trial using fish oil at the earliest stages of the disease, particularly because it is unlikely that a pharmaceutical company will do so, since fish oil in pill form is readily available and inexpensive.
He also said it still needs to be determined what the optimal dose should be.
"It could be that a smaller amount might be helpful, especially in a place like the south of France, where people are already on a Mediterranean diet," he added.
The study is published in the current issue of the Journal of Neuroscience.