A new study offers clues to living longer.

When researchers at the University of Washington engineered mice to produce high levels of an antioxidant enzyme, the mice lived 20% longer and had less heart disease and other age-related problems. If the procedure can be similarly applied to humans, we could be looking at life beyond 100 years.

Dr. Peter Rabinovitch and colleagues bred mice with an abundance of the enzyme catalase. This enzyme acts as an antioxidant by removing damaging hydrogen peroxide, a source of free radicals.

Free radicals have been linked with heart disease, cancer and other age-related diseases. The study supports the notion that free radicals cause aging. Free-radical damage can lead to more flaws in the cell’s chemical processes and more free radicals.

The discovery could lead to future development of drugs or other treatments that protect the body from free radicals, and possibly some age-related conditions, according to Rabinovitch.