Increased consumption of fruits and vegetables has been associated with protection against various age-related diseases. It is not known what dietary constituents are responsible for this association, but it is often assumed that well-characterized antioxidants including vitamins C and E, or beta-carotene contribute to the protection. We hypothesize that the putative beneficial effects of a high intake of fruits and vegetables on the risk of age-related diseases are not exclusively a result of the action of the well-characterized vitamins E and C, or beta-carotene. Rather, they result from the action of other antioxidant phytonutrients or from a concerted action by a combination of different antioxidants present in these foods. Results from our laboratory have shown that many fruits and vegetables have strong antioxidant capacities, and that this is mainly due to non-vitamin C antioxidant phytonutrients. Among these phytonutrients, anthocyanins are an important group of natural products. Anthocyanins are widely distributed in fruits and vegetables, and have been found in human plasma. They exhibit strong antioxidant activities in vitro. The objective of this pilot research program is to test a hypothesis with respect to the in vivo modulation of oxidative stress during aging by anthocyanins. We will feed rats of different ages purified anthocyanins, and measure the anthocyanins and oxygen radical absorbance capacity (ORAC), vitamins C and E, GSH, uric acid, erythrocyte susceptibility to free radical attack, and lipid peroxidation in these animals. The results will tell us (i) if aging affects the absorption of anthocyanins; (ii) if aging affects the total antioxidant capacity, measured as ORAC, and some individual antioxidant levels; and (iii) whether the antioxidant activities exhibited by anthocyanins in vitro can be demonstrated in vivo. The positive data will indicate that anthocyanins are an important part of the antioxidant defense network in the body. The negative data will suggest that anthocyanins may not function as antioxidants in vivo.