Vitamin E and Cognitive Decline in Older Persons

Abstract
OXIDATIVE MECHANISMS may play important roles in neurodegenerative diseases, such as Alzheimer disease1-3 and Parkinson disease,4 and in cellular processes associated with aging.5-7 The brain is especially vulnerable to free radical damage because of its high oxygen consumption rate, its abundance of easily peroxidized lipid membranes, and the presence of relatively few antioxidant enzymes.6 Oxidative reactions induced by reactive oxygen species are thought to cause the degeneration of neurons. Antioxidant nutrients, including vitamin E, vitamin C, and carotene, counteract these processes by inhibiting lipid peroxidation,6,8,9 the generation of reactive oxygen species,10,11 apoptosis,10-12 mitochondrial dysfunction,11 cytotoxic damage to cell membranes,13 and oxidative damage to proteins14-16 and DNA.17-19