By Marcia J. Egles, MD, from “Omega-3 fatty acids: potential role in the management of early Alzheimer’s disease by Gregory A Jicha, in Clinical Interventions in Aging March 24, 2010.
A comprehensive review of the role of omega-3 fatty acids in the treatment of Alzheimer’s disease is encouraging. More than 30 relevant studies from the past decade were evaluated in order to assess the best evidence to date on the topic.
Alzheimer’s disease, a progressive and fatal degenerative brain disorder, is the world’s major cause of dementia. The main microscopic changes in the brains of those affected with Alzheimer’s disease are amyloid plaques and neurofibrillary tangles. Inflammation and oxidative stress are known to be involved in the development of these abnormalities.
Polyunsaturated fatty acids (PUFA), which include omega-3 fatty acids, are known to function as both structural components of nerve cell membranes and as regulators of inflammation, oxidative stress and overall nerve cell health. Amounts of omega-3 PUFAs and omega-6 PUFAs within the membranes can vary with the amounts consumed in the diet and can affect the molecular structure and fluidity of the membranes. The body cannot make these essential fatty acids and must obtain them in the diet. Omega-3 fatty acids have become scarce in the modern diet. Omega-6 fatty acids and saturated fats may be overabundant.
DHA, docasahexanoic acid, is the major omega-3 fatty acid found in nerve cells. A large amount of study data from the past decade suggests an important role for DHA in the prevention of a variety of neurological disorders including Alzheimer’s disease. Reduced dietary or low brain levels of DHA are associated with accelerated mental decline and dementia. Increased consumption of fatty fish has been associated with decreased risk of Alzheimer’s disease. DHA has been shown to be directly involved in the processing of amyloid, the toxic protein which accumulates into amyloid plaques.
Although several clinical trials have investigated omega-3 supplements, none have shown benefit for the treatment of established Alzheimer’s disease. These same studies also suggest that benefits from omega-3 fatty acids may depend on the stage of the disease, other dietary factors such too much omega-6 fatty acids, and underlying genetic types some of which might especially benefit from omega-3 fatty acids.
Several studies have suggested that omega-3 fatty acids may be beneficial if administered prior to the onset of symptoms or in the earliest stages of cognitive decline. The 2006 Freud-Levi study, the first large scale, well designed trial of omega-3 supplements, showed benefits to those only in the earliest stages of Alzheimer’s disease.
The Canadian Study of Health and Aging, rigorously examined plasma fatty acids profiles in 2000. DHA and omega-3 to omega-6 fatty acid dietary ratios were lower in Alzheimer patients.
It is estimated that prior to one hundred years ago, western people consumed about twice as much omega-6 as omega-3 fatty acids. Currently, over twenty times as much omega-6 fatty acids as omega-3’s are in typical diets.
Gary Chandler is a prion expert. He is the CEO of Crossbow Communications, author of several books and producer of documentaries about health and environmental issues around the world. Chandler is connecting the dots to the global surge in neurodegenerative disease, including Alzheimer’s disease, Parkinson’s disease, Creutzfeldt-Jakob disease, chronic wasting disease and other forms of prion disease. The scientific name for prion disease is transmissible spongiform encephalopathy. The operative word is “transmissible.”