Another factor that leads to health consequences from spaceflight is exposure of astronauts to ionizing radiation. Depressed protein metabolism caused decreased anti-oxidant defense that led to more extensive free-radical propagation and irreversible DNA damage. The free radical damage persists for over 2 weeks after these astronauts returned to Earth (probably due to the time necessary to regenerate lost proteins), and caused oxidative stress comparable to that induced by smoking a pack of cigarettes a day. It is hypothesized that dietary antioxidant supplements might improve outcomes.
The hazardous effects of ionizing radiation are well known and depend on total dose and dose rate. They can range from acute radiation illness to death. Cataracts and irreversible genetic damage with an increased risk of early cancers. Use of special anti radiation supplementation with ascorbic acid, vitamin E and beta carotene will enhance cellular repair to injury.