GOED Publishes Review of DHA, Alzheimer’s Study

In the Nov. 3, 2010 issue of the Journal of the American Medical Association (JAMA), researchers reported that the rate of cognitive and functional decline in patients with mild to moderate Alzheimer's disease was not slowed by supplementing with DHA, the most abundant long-chain omega 3 fatty acid in the brain.

The Global Organization for EPA and DHA Omega-3s (GOED), Salt Lake City, UT, has published a Rapid Review analyzing the JAMA study in its Advances in EPA and DHA Research journal. The complete review can be found here.

"While this trial examined DHA's impact on patients who already had Alzheimer’s disease, it's important to keep in mind that most experts emphasize omega 3's benefits likely lie in the prevention or delayed onset of many health conditions, including dementia and Alzheimer's,” said Harry Rice, PhD, vice president of regulatory and scientific affairs, GOED. “Two prior studies, MIDAS and OmegAD, were randomized, double-blind, placebo-controlled trials that showed a benefit to individuals with age-related cognitive decline or very mild Alzheimer's disease, respectively.

"This study leaves open the possibility that DHA supplementation prior to the o

nset of Alzheimer's disease could provide a neuroprotective benefit, such as delayed onset of symptoms and delayed progression of disease,” Dr. Rice continued.

Additionally, the current study did not address other questions about the role omega 3s may play in reducing the risk of Alzheimer's. For instance, the trial did not examine supplementation with EPA, another important omega 3 fatty acid, although research published in the American Journal of Clinical Nutrition in 2008 suggested that a high plasma EPA concentration may decrease the risk of dementia.

Dr. Rice noted that the impact of EPA and DHA on dementia, cardiovascular health and other issues will be examined at the organization's annual conference, the GOED Exchange, in January 2011. More information on the conference and registration details can be found at www.goedexchange.com.

Inability of Liver to Produce DHA May Contribute to Alzheimer’s

UC Irvine researchers have discovered that markedly depleted amounts of an omega 3 fatty acid in brain tissue samples from Alzheimer’s patients may be due to the liver’s inability to produce the complex fat, also contained in fish-oil supplements.

Low levels of docosahexaenoic acid, or DHA, have been associated with the chronic neurodegenerative disease affecting millions of Americans, but no cause had been identified.

In postmortem liver tissue from Alzheimer’s patients, the UCI team found a defect in the organ’s ability to make DHA from shorter molecules present in leafy plants and other foods. Previous studies have shown that most brain DHA is manufactured in the liver.

Non-Alzheimer’s livers did not have this defect, said Daniele Piomelli, the Louise Turner Arnold Chair in the Neurosciences and director of the Center for Drug Discovery at UCI, who led the research with Giuseppe Astarita, project scientist in pharmacology.

“We all know Alzheimer’s is a brain disease, but our findings—which were totally unexpected—show that a problem with liver fat metabolism can make people more vulnerable,” Piomelli said. “They also suggest a reason why clinical trials in which Alzheimer’s patients are given omega-3 fatty acids to improve cognitive skills have had mixed results.”

The study appears Sept. 8 in the open-access, peer-reviewed journal PLoS ONE.

DHA occurs naturally in cold-water fatty fish and seaweed. It is essential for the proper functioning of adult human brains and for the development of our nervous system and vision during the first six months of life. Omega 3 fatty acids are also part of a healthy diet that helps lower risk of heart disease.

“Additionally, we found that the greater the amount of Alzheimer’s-related cognitive problems experienced in life by the patients, the lower were their liver DHA levels,” Astarita said. “So we do see a connection.”

Piomelli added that the results point to new diagnostic and dietary approaches to Alzheimer’s: Specific blood lipid profile tests might identify at-risk persons, and dietary supplements with a chemically enhanced form of DHA may benefit early-stage patients.

“Our research isn’t advocating that liver metabolism is a key to Alzheimer’s,” he noted. “The factors causing the disease are many and complex, but we feel this is another piece in the Alzheimer’s puzzle.”