DHA treatment may be beneficial for Alzheimer’s disease (AD), which is a neurodegenerative disorder with cognitive and short-term memory impairment. The cause of AD is unknown. Many studies have shown that omega-3 fatty acids reduce the risk of AD. Also, dietary DHA protects learning in rats that have been infused with amyloid-beta (a rat model of AD) and helps remove amyloid from the brains of rats. DHA reduces amyloid toxicity in cell culture also.
DHA (docosahexaenoic acid) is the most common omega-3 fatty acid in the brain. It has been found to be essential for growth and development of the brain and the rest of the central nervous system. DHA is produced by microalgae which are eaten by fish. Humans can produce some DHA, but humans can obtain additional DHA by eating fish which eat microalgae. DHA deficiency reduces cognitive impairment and impaired visual acuity. Elderly people and patients with AD commonly have low blood levels of DHA.
Diets which are enriched with omega-3 fatty acids are neuroprotective. Young and old rats showed improved learning after receiving treatment with DHA. The brain is susceptible to oxidative stress because it contains large amounts of omega-3 with DHA, which is easily oxidized. This oxidation can lead to brain tissue damage.
In AD, amyloid increases free radical production in the brain as well as increased oxidation. This has been demonstrated at autopsy. DHA appears to have an antioxidant effect, reducing oxidative stress and preventing memory loss.
Numerous epidemiological studies have been done to show the role of DHA in prevention of Alzheimer’s disease, however the mechanism is unknown and further studies are being done.
CONCLUSION: DHA is believed to reduce cognitive impairment in Alzheimer’s disease by altering amyloid in the brain. It may be of benefit in treating and slowing the onset of Alzheimer’s disease.
NOTE: DHA can be obtained by the use of fish oil from fish which have eaten microalgae. Wild fish are best because they eat algae as a source of their DHA. Farmed fish are fed other foods, such as corn meal.
Amyloid is a deposit of insoluble, fibrous protein. It is associated with Alzheimer’s disease and a total of about 20 diseases, including diabetes and Parkinson’s disease. Amyloid forms tiny fibers in nerve cells and can cause neurodegeneration. Amyloid beta is the best known form of amyloid found in Alzheimer’s disease.
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NOTE: Read about the benefits of benfotiamine form of thiamine (vitamin B-1) in Alzheimer’s disease. Read about homocysteine as a marker of neurodegenerative disease.