Oxidants as Causes of Aging

The free radical theory of aging predicts that oxidants are the cause of aging. There are numerous experimental data supporting this hypothesis (67). However, there are also compelling data that are inconsistent with this hypothesis (68). There are several observations consistent with the free radical theory of aging, including the following:

■ An age-related increase in oxidative damage to a variety of molecules (DNA, protein, and lipid) is present in organisms ranging from single cellular organisms and invertebrates, to humans. For example, a significant increase of oxo8dG levels with increasing age has been observed in nuclear nDNA and mitochondrial mtDNA isolated from various tissues in rodents (69).

TABLE 5 Agents Involved in Protection Against Oxidants

Name

Mechanism(s)

Ascorbic acid (vitamin C)

FR scavenger

Glutathione

FR scavenger, enzyme cofactor

Tocopherol (vitamin E)

FR scavenger

Carotenoids

Singlet oxygen scavengers

Bilirubin

FR scavenger

Lipoic acid

FR scavenger

Uric acid

FR scavenger

Enzyme mimetic

Superoxide, hydrogen peroxide

agents

scavengers

How to Stay Young

How to Stay Young

For centuries, ever since the legendary Ponce de Leon went searching for the elusive Fountain of Youth, people have been looking for ways to slow down the aging process. Medical science has made great strides in keeping people alive longer by preventing and curing disease, and helping people to live healthier lives. Average life expectancy keeps increasing, and most of us can look forward to the chance to live much longer lives than our ancestors.

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