Abstract
Immune function helps to maintain the quality of life (QOL) in elderly subjects. However, age-associated thymic atrophy is reportedly related to alterations in the function of the immune system. Antioxidant status, in terms of parameters such as the activities of superoxide dismutase and glutathione peroxidase in thymocytes, is decreased in aged mice, suggesting that their thymocytes are more susceptible to oxidative stress than those of young mice. Intracellular reactive oxygen species (ROS) are reportedly involved in apoptosis when the cells are damaged by oxidative stress. To clarify the factors that can suppress the increase of intracellular ROS, we analyzed the antioxidant activities of 26 natural antioxidants and found that 13 of them, including flavonoids, eliminated the intracellular ROS induced by oxidative stress. On the other hand, protein known to influence immune function was taken almost equally in Japanese people in all ages. These results show that selective intake of antioxidants in addition to ordinary food may be useful for maintaining or improving the QOL of elderly individuals.
