Fate of superoxide dismutase in mice following oral route of administration.

Superoxide dismutase (SOD) is being sold in the United States under a "false" claim that ingesting SOD pills would prolong the longevity and eliminate needless old age sufferings. We have studied the bioavailability of both radiolabeled [65Zn]-superoxide dismutase (purified) and crude SOD (pills dissolved in normal saline) after intubation of the enzyme into mice. Most of the radioactivity was found to be associated with the fecal material, and feeding SOD (pills) did not affect the plasma and liver levels of SOD. Based on the data collected in the present study, we conclude that SOD taken orally in any form would impart little beneficial effect in controlling the aging process.