“About the safety of eating seafood: Seafood consumption has been a concern because of the increased levels of mercury in fish. This study shows that moderate intake of seafood may produce a decreased chance of developing Alzheimer’s disease.”
The best way to absorb the several findings of this critical study is this YouTube video by one of the authors at Rush Medical Center in Chicago and published in the Journal of the American Medical Association Network. First rate research. https://www.youtube.com/watch?v=m9MncHHHXpA .” Bill Chesnut, MD
Martha Clare Morris, ScD1; John Brockman, PhD2; Julie A. Schneider, MD, MPH3,4,5; Yamin Wang, PhD1; David A. Bennett, MD3,4; Christy C. Tangney, PhD6; Ondine van de Rest, PhD7
JAMA. 2016;315(5):489-497. doi:10.1001/jama.2015.19451.
Importance Seafood consumption is promoted for its many health benefits even though its contamination by mercury, a known neurotoxin, is a growing concern.
Objective To determine whether seafood consumption is correlated with increased brain mercury levels and also whether seafood consumption or brain mercury levels are correlated with brain neuropathologies.
Design, Setting, and Participants Cross-sectional analyses of deceased participants in the Memory and Aging Project clinical neuropathological cohort study, 2004-2013. Participants resided in Chicago retirement communities and subsidized housing. The study included 286 autopsied brains of 554 deceased participants (51.6%). The mean (SD) age at death was 89.9 (6.1) years, 67% (193) were women, and the mean (SD) educational attainment was 14.6 (2.7) years.
Exposures Seafood intake was first measured by a food frequency questionnaire at a mean of 4.5 years before death.
Main Outcomes and Measures Dementia-related pathologies assessed were Alzheimer disease, Lewy bodies, and the number of macroinfarcts and microinfarcts. Dietary consumption of seafood and n-3 fatty acids was annually assessed by a food frequency questionnaire in the years before death. Tissue concentrations of mercury and selenium were measured using instrumental neutron activation analyses.
Results Among the 286 autopsied brains of 544 participants, brain mercury levels were positively correlated with the number of seafood meals consumed per week (ρ = 0.16; P = .02). In models adjusted for age, sex, education, and total energy intake, seafood consumption (≥ 1 meal[s]/week) was significantly correlated with less Alzheimer disease pathology including lower density of neuritic plaques (β = −0.69 score units [95% CI, −1.34 to −0.04]), less severe and widespread neurofibrillary tangles (β = −0.77 score units [95% CI, −1.52 to −0.02]), and lower neuropathologically defined Alzheimer disease (β = −0.53 score units [95% CI, −0.96 to −0.10]) but only among apolipoprotein E (APOE ε4) carriers. Higher intake levels of α-linolenic acid (18:3 n-3) were correlated with lower odds of cerebral macroinfarctions (odds ratio for tertiles 3 vs 1, 0.51 [95% CI, 0.27 to 0.94]). Fish oil supplementation had no statistically significant correlation with any neuropathologic marker. Higher brain concentrations of mercury were not significantly correlated with increased levels of brain neuropathology.
Conclusions and Relevance In cross-sectional analyses, moderate seafood consumption was correlated with lesser Alzheimer disease neuropathology. Although seafood consumption was also correlated with higher brain levels of mercury, these levels were not correlated with brain neuropathology.