Researchers at UCLA’s Alzheimer Disease Research Center have found evidence that fish oils do indeed reduce your chances of developing late-onset Alzheimer’s, and why this is so.

Using tests on both rat and human neuronal tissue (and dietary fish oil in young rats with insulin resistance), they found that even low doses of omega-3 fatty acid docosahexaenoic acid (DHA), found in fish oil, raise the production of LR11. LR11, a protein that exists at excessively low levels among Alzheimer’s disease patients, is known to destroy the protein that forms the toxic amyloid plaques linked to the disease.

They found that high levels of DHA (leading to abundant LR11) seem to protect against Alzheimer’s, while low LR11 levels lead to formation of the plaques. The optimal dose has not yet been determined.

Based on the positive results, the National Institutes of Health is currently conducting a large-scale clinical trial with DHA in patients with established Alzheimer’s disease.

Abstract: “Omega-3 Fatty Acid Docosahexaenoic Acid Increases SorLA/LR11, a Sorting Protein with Reduced Expression in Sporadic Alzheimer’s Disease (AD): Relevance to AD Prevention,” Qiu-Lan Ma et al. The Journal of Neuroscience, December 26, 2007, 27(52):14299-14307