Total antioxidant capacity of diet in relation to cognitive function and decline.

The American journal of clinical nutrition
Q1
Nov 2010
Citations:49
Influential Citations:4
Observational Studies (Human)
80
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Enhanced Details

Methods
Prospective cohort (Nurses’ Health Study). 16,010 women aged ~74 at initial cognitive interview; female health professionals; cognitive function assessed by telephone-based battery on 3 occasions at ~2-year intervals; dietary information collected from 1980 onward via a semiquantitative FFQ; total FRAP scores (foods + supplements) and dietary FRAP scores (foods only) derived by combining FFQ data with FRAP values for foods and supplements; multivariable-adjusted linear regression and linear mixed models used to assess associations.
Results
Higher total FRAP scores (foods + supplements) were associated with better initial global cognitive function and verbal memory after adjusting for age and education (global: mean difference 0.04 standard units, 95% CI 0.01–0.08; verbal: 0.04 SD, 95% CI 0.01–0.08; P-trends 0.003 and 0.02). These associations were attenuated with additional confounder adjustment and not seen for TICS. No significant associations with cognitive decline over ~4 years (P-trend 0.3). Dietary FRAP scores (foods only) showed weaker baseline associations (global: mean difference ~0.03 SD, 95% CI 0.00–0.06; P-trend 0.02) and were not linked to decline (P-trend ~0.4); after full adjustment, global association was borderline (P-trend 0.05; mean difference ~0.02 SD; 95% CI −0.01 to 0.06). Overall, no consistent evidence that higher dietary antioxidant capacity relates to better cognition or slower decline in this cohort of older women. The findings do not support cognitive benefits from antioxidant supplements or high-FRAP diets.
Limitations
Observational design; dietary FRAP scores may poorly capture long-term antioxidant status despite FFQ validation; measurement error in self-reported diet and supplement use; residual confounding possible; generalizability limited to older, predominantly white female health professionals; relatively short follow-up for cognitive decline (~4 years) may limit detection of effects; FRAP is an imperfect proxy for in vivo antioxidant activity.

Abstract

BACKGROUND Epidemiologic evidence on the association of individual antioxidant vitamins and cognition is inconsistent. OBJECTIVE We evaluated the total antioxidant capacity of diets on the basis of the ferric-reducing antioxidant power (FRAP) assay...