Omega 3 fatty acid helps healthy people, but not Alzheimer's patients
By David Liu
One study presented on July 12 at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease (ICAD 2009) in Vienna suggests that taking DHA, a common omega 3 fatty acid may not help people with Alzheimer's disease.
But another study presented at the same conference suggests that this omega 3 fatty acid can help improve memory healthy elderly people in a matter of six months.
"These two studies – and other recent Alzheimer's therapy trials – raise the possibility that treatments for Alzheimer's must be given very early in the disease for them to be truly effective," said William Thies, PhD, Chief Medical & Scientific Officer at the Alzheimer's Association.
"For that to happen, we need to get much better at early detection and diagnosis of Alzheimer's, in order to test therapies at earlier stages of the disease and enable earlier intervention."
DHA or docosahexaenoic acid naturally occurs in the body in small amounts and is found abundant in the brain. DHA can be extracted from some marine microalgae and fatty fish. Because of the concern about the environmental pollution, more people now than ever prefer DHA from microalgae.
Alzheimer's disease, the most common cause of dementia among older people, is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, according to the National Institute on Aging. The disease affects as many as 2.4 to 4.5 million Americans. There is no treatment that can prevent or cure the disease.
The first study involved 402 people aged 76 on average and diagnosed with mild to moderate Alzheimer's at 51 sites in the United States. Joseph Quinn MD associate professor of Neurology at Oregon Health and Sciences University and colleagues gave the participants DHA or placebo at a dose of two grams each day for 18 months. The patients continued taking Alzheimer's drugs during the study.
The researchers found increased levels of DHA in the blood and in the brain the level of DHA seemed to be increased as well. But they did not observe any improvement in brain functions or behavioral symptoms.
However, the researchers did find a lower rate of cognitive decline on the primary test of mental function in people without the ApoE-e4 gene. They said the results need to be confirmed. Overall, DHA has no benefits for Alzheimer's patients.
Dr. Thies said "One of the issues raised by this study – and other recent Alzheimer's and mild cognitive impairment therapy trials – concerns a possible interaction between certain therapies and genetic status. This issue needs to be explored more completely in future trials."
Another study was conducted by Karin Yurko-Mauro, PhD, Associate Director of Clinical Research and colleagues at Martek Biosciences Corporation, which produces the DHA used in both studies.
In their six-month study, the researchers gave 900 mg of algal DHA to 485 healthy older people at an average age of 70 with mild memory complaint for six months.
Those taking DHA supplements made significantly fewer errors on the CANTAB Paired Associate Learning or PAL at the end of the study compared to the results of the test conducted at baseline. Plasma phospholipid DHA levels doubled during the study, which was correlated with the PAL response.
"In our study, healthy people with memory complaints who took algal DHA capsules for six months had almost double the reduction in errors on a test that measures learning and memory performance versus those who took a placebo," Yurko-Mauro said. "The benefit is roughly equivalent to having the learning and memory skills of someone three years younger."
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