To examine the associations of fatty acid and fish intake with cognitive function.

Data are from a cross-sectional population-based study among 1,613 subjects ranging from 45 to 70 years old.
From 1995 until 2000, an extensive cognitive battery was administered and compound scores were constructed for memory, psychomotor speed, cognitive flexibility (i.e., higher order information processing), and overall cognition.
A self-administered food-frequency questionnaire was used to assess habitual food consumption.
The risk of impaired cognitive function (lowest 10% of the compound score) according to the energy adjusted intake of fatty acids was assessed with logistic regression, adjusting for age, sex, education, smoking, alcohol consumption, and energy intake.

Marine omega-3 polyunsaturated fatty acids (PUFA) (eicosapentaenoic acid and docosahexaenoic acid) were inversely related to the risk of impaired overall cognitive function and speed (per SD increase: OR = 0.81, 95% CI 0.66 to 1.00 and OR = 0.72, 95% CI 0.57 to 0.90).
Results for fatty fish consumption were similarly inverse.

Higher dietary cholesterol intake was significantly associated with an increased risk of impaired memory and flexibility (per SD increase: OR = 1.27, 95% CI 1.02 to 1.57 and OR = 1.26, 95% CI 1.01 to 1.57).
Per SD increase in saturated fat intake, the risk of impaired memory, speed, and flexibility was also increased, although not significantly.

Fatty fish and marine omega-3 PUFA consumption was associated with a reduced risk and intake of cholesterol and saturated fat with an increased risk of impaired cognitive function in this middle-aged population.