Oxidative stress plays a causative role in the pathogenesis of neurodegenerative disorders. Vitamin E is a well-known antioxidant; however, little is known about the effect of vitamin E on neurological health. In this study, we investigated the effect of dietary vitamin E deficiency on anxiety-like behavior in rats. Initially, we found that dietary vitamin E deprivation increased anxiety-like behavior in rats subjected to the elevated plus maze test. The anxiety level increased after 2 weeks of vitamin E deprivation and this time point was much earlier than that at which the symptoms of vitamin E deficiency such as ataxia manifested. Because anxiety was not observed in adrenalectomized rats, we believe that glucocorticoid secretion from the adrenal glands plays an important role in the anxiogenic effect of vitamin E deficiency. Furthermore, negative feedback regulation of glucocorticoid secretion was found to be reduced in vitamin E-deficient rats. This finding allowed us to think that increased blood glucocorticoid level and enhanced stress-induced response including anxiety-like behavior in vitamin E-deficient rats were due to the reduction of the negative feedback regulation. These results demonstrate that reduced vitamin E intake may increase the risk of anxiety disorders, especially under stress conditions.
