Do Antioxidants Lengthen Life?

Study: Mice That Make More of an Antioxidant Live Longer

Reviewed by Brunilda Nazario, MD on May 05, 2005

Could antioxidants add years to your life? 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.

What Makes Us Age?

Everyone gets older. But why do health problems often increase along with the number of candles on your birthday cake?

One hypothesis is the "free radical" theory of aging. That's what Rabinovitch and colleagues tested. 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 on the Prowl

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.

These unstable molecules lack a key component. When free radicals try to obtain that component, they kill other cells and damage their DNA, which can lead to abnormalities. Eventually, that takes its toll on the body and ultimately leads to death, according to the theory.

Smoking and pollution can promote the development of free radicals.

Antioxidants Step In

If free radicals are bandits plundering other cells, antioxidants (which help stabilize free radicals) should be the body's knights in shining armor.

Many studies have shown antioxidants' health advantages. There is more ground to cover before experts can pinpoint exactly how much and which sources are best. However, antioxidants are easy to find. You'll automatically get them from a healthy diet that includes fruits, vegetables, whole grains, legumes, and nuts.

Antioxidants are even found in tea as well as a sea of supplements.

Mouse Test

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.

"These results support the free radical theory of aging," write the researchers.

They also found that mitochondria -- the energy generator in each cell -- may be an important source of free radicals.

Show Sources

SOURCES: Schriner, S. Science Express, May 5, 2005. News release, Science. WebMD Feature: "How Antioxidants Work and Which Foods Help."

© 2005 WebMD, Inc. All rights reserved. View privacy policy and trust info