Less Alzheimer’s Seen in Elderly Who Consumed Fish

Eating seafood has a number of well-known health benefits.  The vitamins and minerals in fish protect against heart disease and stroke and are good for brain development.  Now, a new study shows that consuming fish at least once per week, even seafood that contains mercury, lowers the risk of developing Alzheimer’s disease in some people.

Fish is a rich source of omega-3 fatty acids that have been linked to good health.  Several studies suggest fish consumption wards off dementia.

Fish, however, also contains high levels of mercury, a neurotoxin, which researchers have feared could lead to dementia.

Investigators at Rush University Medical Center in Chicago analyzed the brain samples of 286 deceased volunteers for mercury, finding those who ate a lot of fish had the highest levels of the metal in their bodies.

The study, however, also found that fish consumption, at least once per week, seemed to protect some of the elderly participants from Alzheimer’s.  They found higher levels of mercury do not lead to mental decline, as measured by protein deposits in brain tissue

Cindy Lawler, chief at the National Institute of Environmental Health Sciences, says the apparent beneficial effects of seafood are good news.

“Even late in life, moderate fish consumption can have real benefits,» she said. «That stood out to me as a hopeful message.”

Rush researchers found fewer brain changes associated with Alzheimer’s and other forms of dementia among volunteers who regularly ate fish.

This occurred only in a subset of the elderly participants, those who carried a gene called Apoe4, which had put them at higher risk for Alzheimer’s development.

People with Apoe4 have high levels of cholesterol, which are associated with the formation of plaques and tangles in the brain seen in Alzheimer’s.

“Alzheimer’s is such a dreaded disease,» she said. «And I think this can provide some optimism that even if your genes are conspiring against you, in this case, that … it is still possible that you can still have lifestyle changes that can help.”

The volunteers who ate seafood had an average age of 90 at the time of death, another sign that fish consumption is good for you.

The National Institute of Environmental Health Sciences funded the study and its findings were published in the Journal of the American Medical Association.