Free-radical theory
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The Free-radical theory of ageing is that people age because highly reactive molecules known as free radicals or Reactive Oxygen SpeciesTemplate:Ref (ROS) inside cells damage the DNA, protiens and other cellular structures. Dr. Denham Harman, first proposed this theory and his idea has met with much experimental success, and is now considered a major theory of aging.
The reaction of free radicals within cells, and subsequent damage has been linked to a range of disorders including cancer, arthritis, atherosclerosis, alzheimer's and diabetes.
The theory implies that antioxidants such as vitamins E and C, which prevent free radicals from oxidizing (removing electrons from) sensitive biological molecules, will slow the aging process. Dr. Harman launched his theory by showing, for the first time, that feeding a variety of antioxidants to mammals was able to extend their life span.
Recent results published in the journal ScienceTemplate:Ref have demonstrated that, in mice, increasing the amount of an enzyme known as catalase, which facilitates the destruction of hydrogen peroxide (a free radical), increased their life-span by 20%
Notes
- Template:NoteIn biochemistry, the free-radicals of interest are often referred to as Reactive Oxygen Species (ROS) because the most biologically significant free radicals are oxygen-centred, however it should be noted that not all free radicals are ROS and not all ROS are free radicals.
- Template:NoteDOI 10.1126/science.1106653