Influence of vitamin E and C supplementation on lipoprotein oxidation in patients with Alzheimer's disease

Because increased oxidation is an important feature of Alzheimer's disease (AD) and low concentrations of antioxidant vitamins C and E have been obser ved in cerebrospinal fluid (CSF) of AD patients, supplementation with these antioxidants might delay the development of AD. Major targets for oxidatio n in brain are lipids and lipoproteins. We studied whether supplementation with antioxidative vitamins E and C can increase their concentrations not o nly in plasma but also in CSF, and as a consequence decrease the susceptibi lity of lipoproteins to in vitro oxidation. Two groups, each consisting of 10 patients with AD, were for I month supplemented daily with either a comb ination of 400 IU vitamin E and 1000 mg vitamin C, or 400 IU vitamin E alon e. We found that supplementation with vitamin E and C significantly increas ed the concentrations of both vitamins in plasma and CSF. Importantly, the abnormally low concentrations of vitamin C were returned to normal level fo llowing treatment. As a consequence, susceptibility of CSF and plasma lipop roteins to in vitro oxidation was significantly decreased. In contrast, the supplementation with vitamin E alone significantly increased its CSF and p lasma concentrations, but was unable to decrease the lipoprotein oxidizabil ity. These findings document a superiority of a combined vitamin E + C supp lementation over a vitamin E supplementation alone in AD and provide a bioc hemical basis for its use. (C) 2001 Elsevier Science Inc.