Cognitive performance among the elderly and dietary fish intake: the Hordaland Health Study.

BACKGROUND: Increasing evidence suggests that cognitive impairment and dementia in older subjects might be influenced by a diet including seafood. OBJECTIVE: The objective was to examine the cross-sectional relation between intake of different amounts of various seafood (fish and fish products) and cognitive performance. DESIGN: The subjects (n = 2031 subjects; 55% women), aged 70-74 y, were recruited from the general population in Western Norway and underwent cognitive testing. A cognitive test battery included the Kendrick Object Learning Test, Trail Making Test (part A), modified versions of the Digit Symbol Test, Block Design, Mini-Mental State Examination, and Controlled Oral Word Association Test. Poor cognitive performance was defined as a score in the highest decile for the Trail Making Test and in the lowest decile for all other tests. RESULTS: Subjects whose mean daily intake of fish and fish products was >/=10 g/d (n = 1951) had significantly better mean test scores and a lower prevalence of poor cognitive performance than did those whose intake was <10 g/d (n = 80). The associations between total intake of seafood and cognition were strongly dose-dependent; the maximum effect was observed at an intake of approximately 75 g/d. Most cognitive functions were influenced by fish intake. The effect was more pronounced for nonprocessed lean fish and fatty fish. CONCLUSIONS: In the elderly, a diet high in fish and fish products is associated with better cognitive performance in a dose-dependent manner.