Why do people need to supplement SOD?

SOD is an enzyme synthesized by human liver, Chinese name: superoxide dismutase, alias "liver protein", which can effectively balance and eliminate harmful free radicals. With the increase of age, the ability of liver to synthesize SOD gradually weakens. By the age of 40, the ability of liver to synthesize SOD is only half, by the age of 60, only a quarter, and by the age of 80, it is close to zero. Therefore, the supplementation of exogenous SOD is very important.