Seafood Intake Reduces Alzheimer’s Risk for Those with ApoE4 Gene

Investigators from The Netherlands and the United States recently found that seafood consumption is linked to a reduced risk in dementia-associated brain changes in people who carry the ApoE4 gene variation—the largest known genetic risk factor for late-onset sporadic Alzheimer’s disease—and that increased mercury levels associated with consuming fish do not pose a risk for older adults.

The researchers conducted a cross-sectional analyses of deceased persons with Alzheimer’s disease who participated in the Memory and Aging Project clinical neuropathological cohort study, conducted from 2004 to 2013. The mean age at death was 89.9 years, 67% were women, and the mean educational attainment was 14.6 years.

The study evaluated 286 autopsied brains of deceased participants. Dementia-related pathologies assessed were Alzheimer’s disease, the presence of Lewy bodies, and the number of macroinfarcts and microinfarcts. Dietary consumption of seafood and n-3 fatty acids was assessed by a food frequency questionnaire administered annually in the years before death. Tissue concentrations of mercury and selenium were measured using instrumental neutron activation analyses. 

After controlling for age, sex, education, and other factors, the researchers found that, compared with those who ate less seafood, ApoE4 carriers who had one seafood meal or more a week had lower densities of the amyloid plaques and neurofibrillary tangles typical of Alzheimer’s disease. Overall, they had a 47% lower likelihood of having a post-mortem diagnosis of Alzheimer’s disease. Researchers also found that eating seafood was linked to increased mercury in the brain; however, the mercury levels were not linked to the presence of any brain abnormalities.

Although the findings support the benefit of consuming seafood for lowering risk of Alzheimer’s disease, lead author Martha Clare Morris, ScD (Rush University Medical Center, Chicago, IL), warned that no association has yet been found between the quantity of seafood consumed and the level of risk reduction.—Amanda Del Signore