Regularly consuming the catch of the day might be just the thing to keep your brain sharp, shows research published in the Journal of American Medical Association (2016; 315 , 489-97).
Eating at least one portion of fish per week helps to reduce a person's risk of developing Alzheimer's disease and dementia-related illnesses, concluded a team at Rush University Medical Center in Chicago. Begun in 1997, the study monitored elderly people living in Chicago and the surrounding areas. The researchers recorded participants' eating habits and other lifestyle factors. Upon death, the brains of 286 subjects were examined for dementia and Alzheimer's disease.
The researchers found fewer markers of dementia and Alzheimer's disease among elderly people who consumed fish at least once a week than among those who consumed it less frequently. Strikingly, this association was present only among carriers of APOE ε4, the gene that increases the risk of developing Alzheimer's disease and dementia. The scientists observed, however, that even for this population it is still premature to state that eating fish on a weekly basis has a positive influence, since the association has not been demonstrated consistently in other studies.
Another interesting finding centered on the heavy-metal content of fish. We know that eating more fish entails consuming higher concentrations of heavy metals such as mercury, with long-term overconsumption potentially causing damage to the kidneys, liver, brain and nervous system. Researchers found that the more fish research participants ate, the higher their mercury concentrations were. However, these higher concentrations did not correlate with more markers of dementia, so it was not the case that a greater intake of mercury had a negative impact on the brain. In general, the health benefits of consuming fish outweigh the possible negative effects. That said, varying the type of fish consumed is a good idea.