 Research carried out in Italy suggests that healthy centenarians have high levels of vitamin A and vitamin E and that this seems to be important in guaranteeing their extreme longevity.Other research contradicts this and has found that these findings do not apply to centenarians from Sardinia, for whom other factors probably play a more important role.A preliminary study carried out in Poland showed that, in comparison with young healthy female adults, centenarians living in Upper Silesia had significantly higher red blood cell glutathione reductase and catalase activities and higher, although insignificantly, serum levels of vitamin E. Researchers in Denmark have also found that centenarians exhibit a high activity of glutathione reductase in red blood cells.