But here’s good news to all seafood lovers out there.
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Research shows seafood can protect the heart and brain-but it can also contain the heavy metal mercury, which can be especially toxic to brain neurons. Although the researchers found out that those who consumed more seafood had higher brain mercury levels, there is no reason to believe that it has any significant connection to the development of Alzheimer’s disease.
Seafood is high in the long-chain n-3 fatty acid DHA (docosahexaenoic acid), which has established health properties that are specifically related to brain function. They found that seafood consumption was associated with increased mercury levels in the brains but not the amount of beta amyloid protein plaques and tau protein tangles, the hallmarks of Alzheimer’s disease.
Martha Clare Morris, Sc.D., of Rush University Medical Center, Chicago, and colleagues examined whether seafood consumption is correlated with increased brain mercury levels and also whether seafood consumption or brain mercury levels are correlated with brain neuropathologies.
But some older people worry that consuming fish with mercury will actually damage their brains, she said, so this study should allay those concerns.
‘Current research is underway to investigate the benefits of a diet rich in omega-3 fatty acids in those at risk of memory and thinking problems, but at this time there is no evidence to suggest fish oil supplements could prevent dementia.
In models adjusted for age, sex, education, and total energy intake, seafood consumption (one or more meal[s]/week) was significantly correlated with less Alzheimer disease pathology, including lower density of neuritic plaques, less severe and widespread neurofibrillary tangles and lower neuropathologically defined Alzheimer disease, but only among apolipoprotein E (APOE ε4) carriers, a gene variant associated with an increased risk of developing Alzheimer disease.
Morris also noted that this cohort had moderate levels of seafood consumption, so the findings can’t be generalized to populations with higher seafood intake or higher mercury exposure.
Dr Laura Phipps at Alzheimer’s Research UK, said: ‘The omega-3 fatty acids found in oily fish are an important part of a balanced diet, and previous studies suggest they could play an important role in keeping the brain healthy. People with APOE-4 are thought to lose even more DHA in the brain, so seafood consumption could be even more beneficial to them, Morris added.
The study in the Journal of the American Medical Association (JAMA) was based on the autopsies of 286 people who died at an average age of 90. “This may give us some clue as to why eating seafood could benefit some people over others – but we need further work to find out if this is the case”. However another study will be coming out soon that looks at the relationship between seafood consumption and cognitive decline in this group of older adults, Morris said. Some autopsy studies found increased mercury levels in brain tissues of AD patients.
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A new study shows that eating at least one seafood meal per week is linked to a reduced risk of having Alzheimer.
