It's a controversial topic, say researchers who recently tested the theory in mice.
Peter Rabinovitch, MD, PhD, and colleagues don't have the final answer.
But they did find that mice that made more of an antioxidant called catalase lived longer than normal.
How much extra time did the mice get?
About five months, on average -- an 18.5% increase in life span for a mouse, says the study.
Heart disease, cataract development, and other signs of age-related damage were delayed or reduced, the researchers report in Science Express, the advance online edition of Science.
But why do health problems often increase along with the number of candles on your birthday cake?
One hypothesis is the "free radical""free radical" theory of aging.
They say there have been contradictory findings in aging tests conducted on invertebrate animals like fruit flies and that most mouse experiments on longevity haven't directly tested the theory.
Free radicals are unstable molecules that damage cells by interfering with their normal functioning.
Some experts believe that the free-radical damage results in age-related diseases, such as cataracts and heart disease.
When free radicals try to obtain that component, they kill other cells and damage their DNA, which can lead to abnormalities.
Many studies have shown antioxidants' health advantages.
You'll automatically get them from a healthy diet that includes fruits,fruits, vegetables, whole grains, legumes, and nuts.
Antioxidants are even found in teaAntioxidants are even found in tea as well as a sea of supplements.
The mice in Rabinovitch's study didn't eat a special diet or gobble antioxidant supplements.
Instead, their genes were manipulated to make more catalase than usual.