February 27th, 2012
04:01 PM ET
People with diets short on omega-3 fatty acids – the kind found in fish oil – were more likely to experience accelerated brain aging, a new study found.
“People with lower levels of omega-3 fatty acids had lower brain volumes that were equivalent to about two years of brain aging,” said Dr. Zaldy S. Tan, a member of the UCLA Easton Center for Alzheimer’s Disease Research in the Department of Neurology.
The study was published Tuesday in the print edition of the journal Neurology.
Tan and his colleagues compared blood levels of two nutrients in omega-3 fatty acids with MRI brain scans and cognitive tests. They found people in the bottom 25% scored lower on such mental tests as problem solving, multi-tasking and abstract thinking.
Tan said the MRI images showed those with lower levels of omega-3 fatty acids were also more likely to have minute but significant structural changes in the brain. The MRIs showed higher white matter hyperintensity volume, tiny lesions in the brain, raising the risk for death, stroke and dementia for the low omega-3 fatty acids group.
Tan said the results were consistent with signs of damage to the intricate network of blood vessels in the brain. A third of the brain by volume is composed of blood vessels.
Tan’s team studied 1,575 people with an average age of 67 who were free of dementia. They controlled for such risk factors as age, smoking, gender, body mass index, physical activity and APOE, the one known gene linked to dementia risk.
Tan said the next step in the research is to follow these people to see if the risk factors they observed translates into a higher rate of cognitive deterioration.
Fatty fish like salmon offer a concentrated source of the omega-3 fatty acid nutrients Tan and his colleagues looked at eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
Vegetable and canola oils, soybeans, flaxseed, walnuts and vegetables including spinach, kale and salad greens are also a source of omega-3 fatty acids. These contain alpha-linolenic acid (ALA), which the body partially converts to EPA and DHA.
Both types are thought to be beneficial. The typical American diet doesn't contain enough of either. Choose My Plate, the government’s dietary guidelines, recommends eating seafood twice a week.
“This is an important new finding that supports omega-3 for brain health and brain size,” said Dr. Majid Fotuhi, chairman of the Neurology Institute for Brain Health and Fitness and assistant professor of neurology at Johns Hopkins University School of Medicine.
Fotuhi recommends his patients get 1,000 mg per day of DHA, a nutrient that increases blood flow in the brain, reduces inflammation in the brain, heart and elsewhere, and reduces the toxic aggregation of amyloid in the brain.
DHA has the added benefit of improving mood and reducing symptoms of depression, he said. The only people who should avoid DHA are patients on a blood thinner like Cumadin, he added.
Neurology, published weekly, is the official journal of the American Academy of Neurology.
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