The exact mechanism by which the omega-3 fatty acid DHA deters Alzheimer’s disease has been determined. Fish oil has long been advocated as an affordable supplement to prevent or at least delay this disease. Finally, UCLA scientists have confirmed this claim and now know the details of the underlying mechanism.
Greg Cole, professor of medicine and neurology at UCLA (University of California in Los Angeles) and associate director of UCLA’s Alzheimer Disease Research Center, and his colleagues have determined that the presence of the omega-3 fatty acid docosahexaenoic acid (DHA) near neurons increases production of a protein called LR11. Found at low levels in Alzheimer’s patients, this protein functions as a destroyer of the plaques in the brain believed to cause the disease.
These plaques are made of misfolded proteins called beta amyloid that are thought to be deadly to neurons. Since the plaques are formed in the brain many years before symptoms of the disease are observed, DHA should be included as a preventative measure rather than as a treatment.
The researchers investigated this mechanism of action by three approaches. Applying just low doses of DHA directly to rat neurons grown in the laboratory resulted in the increase of LR11 by the neurons. Adding a source of DHA to the diets of rats and older mice genetically manipulated to develop Alzheimer’s disease also increased LR11 production by neurons. To confirm the same mechanism in humans, high doses of DHA were applied directly to human neuronal cells grown in culture and this lead to an abundance of LR11. However, adding a source of DHA to the human diet was not studied by these researchers and the optimal dose to produce a healthy amount of LR11 is unknown.
DHA is one of three omega-3 fatty acids crucial to human nutrition, the other two being alpha-linolenic acid (ALA) and eicosapentaenoic acid (EPA). It is important to obtain each of these “essential” fatty acids in one’s diet because they can not be manufactured by the body. Besides fish oil supplements and oily fish such as salmon, vegetarians and vegans can obtain DHA from chia, flax, and many types of nuts and seeds.
Furthermore, low levels of DHA have shown a correlation with ADHD and depression among other diseases. Low DHA results in reduction of brain serotonin levels. The American Heart Association has endorsed omega-3 fatty acids as a preventative measure against heart disease.
DHA is the most prevalent essential fatty acid in the brain and is crucial to fetal and infant brain development. It has been added to infant formulas in recent years in recognition of this fact. Infant formulas come from plants or animals, none of which have the unique cognitive requirements of humans. Despite formulas having all the known nutrients for brain and body development, it’s conceivable that there are others yet to be discovered. Perhaps a healthy mother’s body “knows” best the requirements of her children.