What Seafood Could Do for Dementia Risk

Seafood consumption may reduce Alzheimer’s disease risk for the genetically predisposed

(RxWiki News) Despite its many nutritional benefits, seafood contains mercury — a known neurotoxin. But new evidence suggests eating seafood may actually lower the risk for one neurological disorder.

A new study found that older adults who carried a high-risk gene for Alzheimer’s disease, called APOE-ε4, who also ate at least one serving of seafood per week showed fewer signs of Alzheimer’s-related brain changes. No such link was found in patients who didn’t carry the gene.

This finding is significant considering that as many as 5 million Americans had Alzheimer’s disease in 2013 — a number projected to increase to nearly 14 million by 2050, according the Centers for Disease Control and Prevention (CDC).

Alzheimer’s disease is the most common form of dementia. Dementia is a general term for a decline in mental ability severe enough to interfere with daily life.

A team of researchers at Rush University and others wanted to determine whether seafood intake was related to mercury levels in the brain, and whether seafood or mercury played a role in certain brain changes that contribute to Alzheimer’s disease and other forms of dementia.

For this study, researchers used data from the Memory and Aging Project (MAP) study to look at older participants who were cognitively normal at the beginning of the study, but eventually developed dementia. Participants also completed annual dietary surveys every year for several years.

Researchers looked at the brains of 286 deceased participants who were age 89.9 on average at the time of death. Sixty-seven percent were women.

The brains were analyzed for neuropathologies, or detrimental brain changes, tied to different types of dementia. Levels of mercury in the brains were also examined.

Seafood intake was linked to higher levels of mercury in the brain, but not the amount of beta amyloid protein plaques and tau protein tangles — two known hallmarks of Alzheimer's disease. In fact, researchers found that participants who ate a moderate amount of seafood had less Alzheimer’s disease neuropathologies than participants who didn't.

Researchers noted that these findings may not apply to all groups.

This study was published Feb. 2 in the journal JAMA.

Information on funding sources and conflicts of interest was not available at the time of publication.

Review Date: 
February 3, 2016