OHSU Neurologists Studying Fish Oil as Alzheimer's Therapy

06/02/04    Portland, Ore.

 

The same fish oil rich in the omega-3 fatty acids that reduce your risk for cardiovascular disease may also help slow the progression of Alzheimer's disease.

An integrative team of researchers, neurologists and a naturopath at Oregon Health & Science University is studying fish oil alone and a combination of fish oil and alpha lipoic acid (ALA) as potential therapies for Alzheimer's disease.

Researchers are recruiting volunteers - men and women, ages 55 and older, with cognitive impairment - to take part in a double-blind, placebo-controlled clinical study, which is funded by a two-year, $250,000 grant from the National Institute on Aging, National Institutes of Health.

Lynne Shinto, N.D., assistant professor of neurology and the project's lead investigator, said the study will examine the effects of fish oil and the fish oil-ALA combination on people with mild cognitive impairment who have Alzheimer's disease.

The goal is to determine whether the compounds decrease oxidative stress, a condition believed to be linked to Alzheimer's disease in which an overabundance of oxygen molecules produce free radicals that damage neurons. Researchers also will look at the effect on two other suspected Alzheimer's risk factors: inflammation and increased cholesterol levels. Researchers will then study the clinical outcomes of the treatments and hope to use the results to design a larger clinical trial.

This study will evaluate the capabilities of fish oil and ALA, a strong antioxidant, to decrease levels of these biological markers associated with Alzheimer's disease. If these compounds are able to decrease blood measures of oxidation, inflammation, and lipid levels, Shinto said.

"The ultimate outcome is to be able to look at these (treatments) as a potential preventive formula - if someone could take a gram or two grams a day of fish oil before signs of the disease, it's preventive in that it's either decreasing the chance of turnover to Alzheimer's disease or it's delaying its progression," she said. "And I like the idea of using something that is cheap, accessible and easy to take."

Two-thirds of the study participants will be assigned to receive either an active supplement of fish oil alone or fish oil with alpha lipoic acid; one-third of the participants will be assigned to a placebo or inactive pill. Participants will be assigned at random.

Oxidative damage and inflammation are believed to play an important role in functional changes to nerve cells in the brain that occur during Alzheimer's disease, making treatment with anti-inflammatory and antioxidant properties a promising approach for slowing its progression. Fish oil, particularly that of cold water fish such as salmon, contains high levels of omega-3 fatty acids that possess anti-inflammatory and lipid-lowering capabilities.

Population studies have shown a decrease in Alzheimer's risk in people who eat one or more servings of fish per week. Previous studies have shown that people with the disease have low levels of one type of omega-3 fatty acid, docosahexaenoic acid, or DHA.

"A lot of people feel DHA is really the important one with Alzheimer's disease," Shinto said. "DHA is clearly depleted in people with Alzheimer's. The feeling is these essential fatty acids are important in signal transduction in cells, but nobody actually knows the exact mechanism by which they're working and what specific fatty acids or ratio of fatty acids is ideal for optimal neuronal function."

ALA helps restore levels of other antioxidants, such as vitamin C, vitamin E and glutathione, and repair oxidative damage.

"The reason we included alpha lipoic acid is it's highly antioxidant," Shinto said. "Using this great antioxidant may have a greater treatment effect. We're hitting the disease from many mechanistic levels."

Barry Oken, M.D., professor of neurology and behavioral neuroscience in the OHSU School of Medicine and a study collaborator, said a goal of the fish oil study is to dispel myths about the supplement's efficacy.

"Some people with Alzheimer's disease use various dietary supplements in the belief that they may provide some benefit, even though the evidence on many of these supplements is less than for conventional pharmaceuticals," said Oken, who directs the Oregon Center for Complementary and Alternative Medicine in Neurological Disorders (ORCCAMIND) at OHSU.

Two therapies with relatively more evidence are high-dose vitamin E and ginkgo biloba extract, Oken said. Other therapies with varying degrees of evidence include B-complex vitamins, citicholine, phosphatidylserine and huperzine A.

Fish oil and ALA are among several complementary therapies being investigated by ORCCAMIND and OHSU's Layton Center for Aging & Alzheimer's Disease Research for their effects on cognitive function. Studies have ranged from clinical trials of lactoferrin for treating Alzheimer's disease to the use of yoga and the herbal supplement bacopa by healthy seniors, to various natural antioxidants in animal models of Alzheimer's.

Volunteers are being recruited for the study. For more information, call Sara Baldauf-Wagner at 503 494-3549. Callers will be given an initial qualifying screening over the phone.

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