Atherosclerosis and thrombosis may lead to cognitive impairment through cerebral infarcts or white matter hyperintensities. Oxidative stress is now seen as a major contributor to the process of atherogenesis. High intake of polyunsaturated fatty acids, e.g., linoleic acid, or low intake of antioxidants can increase oxidative stress. High intake of n-3 polyunsaturated fatty acids and its main source, fish, may reduce the risk of thrombosis. Little is known, however, about the relation between these dietary factors and cognitive function. The authors investigated this relation with data derived from a cohort of men, aged 69-89 years, who were participants in the Zutphen Elderly Study. The 30-point Mini-Mental State Examination was used to assess cognitive impairment in 1990 (score < or = 25 in 153/476 men, 32%) and cognitive decline from 1990 to 1993 (drop > 2 points in 51/342 men, 15%). Food intake was estimated in 1985 and 1990 by the cross-check dietary history method. High linoleic acid intake was associated with cognitive impairment after adjustment for age, education, cigarette smoking, alcohol consumption, and energy intake (odds ratio (OR) for highest vs. lowest tertile = 1.76, 95% confidence interval (CI) 1.04-3.01). Intake of n-3 polyunsaturated fatty acids was not associated with cognitive impairment, whereas high fish consumption tended to be inversely associated with cognitive impairment (OR = 0.63, 95% CI 0.33-1.21) and cognitive decline (OR = 0.45, 95% CI 0.17-1.16). Intakes of beta-carotene, vitamins C and E, and flavonoids were not inversely associated with cognitive impairment or decline. This study raises the possibility that high linoleic acid intake is positively associated with cognitive impairment and high fish consumption inversely associated with cognitive impairment.