The old wives used to claim that fish is brain food. Now a group of high-powered California scientists seem to have confirmed this idea, studying a fat from fish.
What Is the Relationship Between Fat from Fish and Brain Health?
The scientists recruited volunteers from the Aging Brain Study and analyzed their serum levels of docosahexaenoic acid, abbreviated DHA. This fatty acid comes from fish or fish oil.
The 61 study participants also underwent brain imaging to detect amyloid plaques. These are linked to Alzheimer disease.
People with higher blood levels of DHA had lower amounts of amyloid plaque in their brains.
In addition, those with higher DHA levels had better scores on a test of nonverbal memory. Areas of their brains usually damaged by Alzheimer were larger and presumably healthier. Alzheimer disease is frequently associated with brain shrinkage.
The authors warn that “limited seafood intake may increase the risk of brain amyloid deposition and Alzheimer disease.”
A few previous studies have found a connection between a diet rich in fish or seafood and a reduced risk of dementia or cognitive decline. We wrote about a meta-analysis of 21 studies here.
Unfortunately, studies have shown that taking fish oil or the fat from fish, DHA, in a supplement may not be able to prevent or reverse Alzheimer disease. (You can read about those studies here and here.)
Downsides of DHA:
In addition, while DHA may help protect the brain from alcohol-induced damage, some studies suggest that men taking DHA supplements may be more likely to develop aggressive prostate cancer. (We wrote about another study of DHA and prostate cancer here.) While most studies suggest that eating fish or seafood is beneficial for the heart or the joints, it is not clear whether eating more fish might put men at higher risk of this potentially deadly cancer.