OBJECTIVES: To prospectively assess effects of select dietary fats on cognitive decline.
DESIGN: Prospective observational; 3-year follow-up.
SETTING: Northwestern University.
PARTICIPANTS: Four hundred eighty-two women aged 60 and older who participated in the Women's Health Initiative (WHI) Observational Study or in the control group of the WHI Diet Modification arm.
MEASUREMENTS: Dietary intake from a validated food frequency questionnaire (FFQ) administered twice (mean 2.7 years apart) before baseline cognitive assessment (mean 2.9 years after second FFQ) was averaged. Testing of memory, vision, executive function, language, and attention was performed twice, 3 years apart. A global Z-score was created for both time points by averaging all Z-scores for each participant, and global cognitive change was defined as the difference between follow-up and baseline Z-scores.
RESULTS: Median intake of saturated fat (SFA), trans-fat, (TFA), dietary cholesterol (DC), and monounsaturated fat (MUFA) was 18.53, 3.45, 0.201, and 19.39 g/d, respectively. There were no associations between degree of cognitive decline and intake of SFA (P=.69), TFA (P=.54), or DC (P=.64) after adjusting for baseline cognition, total energy intake, age, education, reading ability, apolipoprotein E ɛ4 allele, body mass index, estrogen and beta-blocker use, and intake of caffeine and other fatty acids. In contrast, MUFA intake was associated with lower cognitive decline in fully adjusted linear regression models, with mean decline (standard error) of 0.21 (0.05) in the lowest and 0.05 (0.05) in the highest quartiles (P=.02). This effect of MUFA intake was primarily in the visual and memory domains (P=.03 for both).
CONCLUSION: Greater intake of SFA, TFA, and DC was not associated with cognitive decline, whereas greater MUFA intake was associated with less cognitive decline.