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.
Fish oil and its key ingredient, omega-3 fatty acids (found in fatty fish like salmon), have been a mainstay of alternative health practitioners for years and have been endorsed by the American Heart Association to reduce the risk of cardiovascular disease.
Fatty acids like DHA are considered "essential" fatty acids because the body cannot make them from other sources and must obtain them through diet. Years of research have shown that DHA is the most abundant essential fatty acid in the brain, Cole said, and that it is critical to fetal and infant brain development. Studies have also linked low levels of DHA in the brain to cognitive impairment and have shown that lower levels may increase oxidative stress in the brains of Alzheimer's patients.
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. For those patients, Cole said, it may be too late in the disease's progression for DHA to have much effect. But 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.
Still to be determined, he said, "is what th
|Contact: Mark Wheeler|
University of California - Los Angeles