Relation of the tocopherol forms to incident Alzheimer disease and to cognitive change

Abstract

Background: High intake of vitamin E from food (tocopherol), but not from supplements (which usually contain α-tocopherol), is inversely associated with Alzheimer disease. Objective: We examined whether food intakes of vitamin E, α-tocopherol equivalents (a measure of the relative biologic activity of tocopherols and tocotrienols), or individual tocopherols would protect against incident Alzheimer disease and cognitive decline over 6 y in participants of the Chicago Health and Aging Project. Design: The 1993-2002 study of community residents aged ≥65 y included the administration of 4 cognitive tests and clinical evaluations for Alzheimer disease. Dietary assessment was by food-frequency questionnaire. Results: Tocopherol intake from food was related to the 4-y incidence of Alzheimer disease determined by logistic regression in 1041 participants who were clinically evaluated (n = 162 incident cases) and to change in a global cognitive score determined by mixed models in 3718 participants. Higher intakes of vitamin E (relative risk: 0.74 per 5 mg/d increase; 95% CI: 0.62, 0.88) and α-tocopherol equivalents (relative risk: 0.56 per 5 mg/d increase; 95% CI: 0.32, 0.98) were associated with a reduced incidence of Alzheimer disease in separate multiple-adjusted models that included intakes of saturated and trans fats and docosahexaenoic acid, α- and γ-Tocopherol had independent associations. In separate mixed models, a slower rate of cognitive decline was associated with intakes of vitamin E, α-tocopherol equivalents, and α- and γ-tocopherols. Conclusion: The results suggest that various tocopherol forms rather than α- tocopherol alone may be important in the vitamin E protective association with Alzheimer disease. © 2005 American Society for Clinical Nutrition.