How Eating Fish May Help Our Brains

July 21, 2014

People with high blood levels of the “good” fats found in fish had more robust brains than those with low levels of those fats, a new study reports. The findings add to a growing body of evidence that eating fish – or taking fish oil supplements – may be good for brain health in old age.

For the study, researchers looked at blood levels of omega-3 fatty acids, the “good” fats found in fish. Oily fish like salmon, sardines, tuna and mackerel are particularly rich in omega-3s, as are some leafy greens, and flaxseed oil.

The researchers found that the brains of older people who had higher levels of omega-3s were larger than the brains of those with low omega-3 levels. Larger brain volumes are generally associated with preservation of memory and thinking skills. Shrinking brain volumes, on the other hand, can be a sign of Alzheimer’s disease. The findings appeared in Neurology, the medical journal of the American Academy of Neurology.

While brains normally shrink as we grow older, having high omega-3 levels seems to slow this process. People with the highest levels of omega-3s had brain volumes that were the equivalent of preserving one to two years of brain health, the researchers found.

For the study, researchers looked at 1,111 women, average age around 70, who were part of the Women’s Health Initiative Memory Study. Omega-3 blood levels were tested at the start of the study. The scientists measured two types of omega-3s thought to be particularly beneficial for brain health: DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid).

Eight years later, when the women were in their late 70s, they were given MRI brain scans to assess brain volume. Those who had higher levels of omega-3s had larger brain volumes than those with low levels of the fatty acids. Brain volume was particularly well preserved in the hippocampus, a part of the brain critical for memory.

“These higher levels of fatty acids can be achieved through diet and the use of supplements,” said study author James V. Pottala, of the University of South Dakota in Sioux Falls. “The results suggest that the effect on brain volume is the equivalent of delaying the normal loss of brain cells that comes with aging by one to two years.”

The typical middle-aged American woman has about a 20 percent chance of developing Alzheimer’s or another form of dementia in old age, the researchers note. A fish-heavy diet or supplementation with fish oil pills could help preserve brain function by preserving brain volume. Reduced brain volume typically occurs as part of the course of Alzheimer’s disease, and shrinking of the hippocampus often precedes symptoms like severe memory loss and thinking problems.

Earlier research has found that seniors with the highest levels of DHA were up to 50 percent less likely than those with the lowest DHA levels to develop Alzheimer’s or other types of dementia. This study showed that high omega-3 levels help fight brain shrinkage.

In addition to preserving brain volume, fish oils may help by reducing inflammation, which is linked to a variety of chronic illnesses, including heart disease and Alzheimer’s. Omega-3s are also thought to preserve the health of blood vessels, including those in the brain.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: James V. Pottala, PhD; Kristine Yaffe, MD, Jennifer G. Robinson, MD, MPH, et al: “Higher RBC EPIA plus DHA Corresponds With Larger Total Brain And Hippocampal Volumes: WHIMS-MRI Study.” Neurology Vol. 82, pages 435-442, January 2014.


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