Quick Study

Quick Study: Pace of dementia seems unaffected by fish oil

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Monday, November 15, 2010; 4:28 PM


Pace of dementia does not seem to be affected by fish oil supplements

THE QUESTION Might taking fish oil supplements slow the mental decline of people with Alzheimer's disease?

THIS STUDY randomly assigned 402 people, who averaged 76 years old and had mild to moderate Alzheimer's, to take two grams of fish oil (containing docosahexaenoic acid, or DHA) or a placebo daily. About a fourth of the participants had MRI scans of their brains done at the beginning and end of the study. Everyone's cognitive and functional abilities were tested periodically. After 18 months, ratings on standardized scales showed virtually no difference in the amount of cognitive decline, including such things as memory, attention, language and orientation, between people who took the supplements and those who did not. Also, MRIs revealed essentially no differences between the two groups in the rate at which their brains were shrinking, which occurs with dementia.

WHO MAY BE AFFECTED? People with Alzheimer's disease, a progressive brain disease that gradually destroys people's memory and thinking ability, eventually making it impossible for them to continue their normal daily activities. At least 5 million Americans have the disease, a number that is expected to increase dramatically as the population ages.

CAVEATS The authors suggested that the findings might be different if people were to start taking fish oil earlier, before any symptoms of Alzheimer's were present. Two of the 12 primary authors were employees of Martek Biosciences, which makes DHA and provided the supplements and placebos for the study.

FIND THIS STUDY Nov. 3 issue of the Journal of the American Medical Association .

LEARN MORE ABOUT Alzheimer's disease at www.nia.nih.gov and www.alz.org.

- Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.

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