The risk for dementia, a major contributor to incapacitation and institutionalization, rises rapidly as people age, doubling every 5 years after age 65. Tens of millions of new Alzheimer's disease (AD) and other dementia cases are projected as elderly populations increase around the world, creating a projected dementia epidemic for which most nations are not prepared.
Researchers believed that "there is an urgent need for prevention approaches that are safe, effective, and affordable. This review addresses the potential of one promising candidate, the omega 3 fatty acid docosahexaenoic acid (DHA), which appears to slow pathogenesis of AD and possibly vascular dementia." DHA is pleiotropic, acting at multiple steps to reduce the production of the beta-amyloid peptide, widely believed to initiate AD. DHA moderates some of the kinases that hyperphosphorylate the tau-protein, a component of the neurofibrillary tangle.
DHA may help suppress insulin/neurotrophic factor signaling deficits, neuroinflammation, and oxidative damage that contribute to synaptic loss and neuronal dysfunction in dementia. Researchers conclude that DHA increases brain levels of neuroprotective brain-derived neurotrophic factor and reduces the omega 6 fatty acid arachidonate and its prostaglandin metabolites that have been implicated in promoting AD. Clinical trials suggest that DHA or fish oil alone can slow early stages of progression, but these effects may be apolipoprotein E enotype specific, and larger trials with very early stages are required to prove efficacy. "We advocate early intervention in a prodromal period with nutrigenomically defined subjects with an appropriately designed nutritional supplement, including DHA and antioxidants" reasearchers state.
Numerous studies support role of DHA on cognition and synaptic integrity. In another recent study researchers at the University of Lorraine in France conclude from a review of the research that the omega-3 fat DHA is one of the "..most valuable diet ingredients whose neuroprotective properties could be crucial for designing nutrition-based strategies able to prevent Alzheimer's disease." DHA (docosahexaenoic acid) makes up a critical component of nerve cell membranes, allowing them more fluidity and enhancing nerve cell communication, as well as increasing their survival, thus reducing risk for degeneration associated with dementia.
Oster T, Pillot T: Docosahexaenoic acid and synaptic protection in Alzheimer's disease mice. Biochimica et Biophysica Acta 2010; March 6th. Cole G, Frautschy S: DHA may prevent age-related dementia. Journal of Nutrition 2010; 140:869-874.