Plasma antioxidants and longevity: a study on healthy centenarians.

A large body of experimental research indicates that oxidative stress contributes to the processes related to aging and to the pathogenesis of several age-related diseases. Vitamins and antioxidant enzymes have a fundamental role in defending the organism from oxidative stress. To better understand the role of antioxidants in human aging, we measured plasma levels of vitamin C (ascorbic acid), uric acid, vitamin E (alpha-tocopherol), vitamin A (retinol), carotenoids, total thiol groups, and the activity of plasma superoxide dismutase (SOD) and glutathione peroxidase (GPX) as well as the activity of red blood cell (RBC) SOD in 32 healthy centenarians-17 elderly subjects aged 80-99 years, 34 elderly subjects aged 60-79 years, and 24 adults aged less than 60 years. Considering the "noncentenarians" only, we observed a consistent behavior in the antioxidant pattern, with a decrease of the nonenzymatic antioxidants and an increase of the enzymatic antioxidant activities relative to age. Remarkably, centenarians were characterized as having the highest levels of vitamins A and E, whereas the activities of both plasma and RBC SOD, which increase with age, decreased in centenarians. From these results, it is evident that healthy centenarians show a particular profile in which high levels of vitamin A and vitamin E seem to be important in guaranteeing their extreme longevity.