In 2016 a large study confirmed findings from 21 cohort studies (181,000 people)that supported that fish consumption was protective against the risk of dementia and Alzheimer’s disease. It was published in the American Journal of Clinical Nutrition and recommended “fishery products” for a lower risk of cognitive impairment.
Source: Y. Zhang, et al., “Intakes of Fish and Polyunsaturated Fatty Acids and Mild-to-Severe Cognitive Impairment Risks: A Dose-Response Meta-Analysis of 21 Cohort Studies, American Journal of Clinical Nutrition 103, no 2 (2016):330-40.
FOOD, FACTS and FADS 