| Free-radical Theory |
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| aging | |
| free radicals | |
| gerontology | |
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In 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. Denham Harman first proposed this theory that aging was a consequence of free radical damage in the 1950s (PMID 13332224) and extended the idea over subsequent decades. Of all the Theories Of Aging , Harman's has the most consistent experimental support. THEORY OF DISEASE One of the underlying concepts that guided Harman to his theory of aging was the involvement of free radicals in disease. Free radical damage within cells, and subsequent damage has been linked to a range of disorders including Cancer , Arthritis , Atherosclerosis , Alzheimer's Disease , and Diabetes . This involvment is not at all surprising as free radical damage is an important aspect of Phagocytosis , Inflammation , and Apoptosis . Cell suicide, or apoptosis, is the body's way of controlling cell death and involves free radicals and redox signalling. Redox factors play an even greater part in other forms of cell death such as Necrosis or Autoschizis . More recently, the relationship between disease and free radicals has led to the formulation of a greater generalisation. The free radical theory of disease states that disease is associated with abnormal levels of oxidation and the generation of free radical damage. In its strong form, the hypothesis states that all disease depends upon free radical damage. The weaker statement of the hypothesis is that disease generally involves free radical processes. EVIDENCE
ANTIOXIDANT THERAPY The theory implies that Antioxidants (e.g. Vitamin A , Vitamin C , and Vitamin E ) — which prevent free radicals from Oxidizing sensitive biological molecules, or reduce the formation of free radicals — will slow the aging process and prevent disease. The antioxidant chemicals found in many food-stuffs (such as the well known vitamins A, C and E) are frequently cited as the basis of claims for the benefits of a high intake of Vegetable s and Fruit s in the diet. In particular, antioxidant therapy forms the basis of many basic pharmacological interventions and particularly Orthomolecular Medicine . A particularly interesting development, the Dynamic Flow model, is a hypothesis originating with the suggestion by Dr. Robert Cathcart that massive intakes of ascorbate can quench disease processes. CALORIE RESTRICTION ''See main article: Calorie Restriction '' ''Calorie restriction'', or severely cutting the intake of energy, has been found to reduce ROS and to increase the life-span of rodents. Studies have shown that both calorie restriction and reduced meal frequency/intermittent fasting can suppress the development of various diseases and can increase life span in rodents by 30-40% by mechanisms involving stress resistance and reduced oxidative damage. Severe calorie restriction over 50% resulted in increased mortality (PMID 16011467). The greatest proponent of calorie restriction as a way to longer life was the late Dr. Roy Walford (''1924-2004''), formerly Professor of Pathology at the University Of California, Los Angeles School of Medicine. SEE ALSO EXTERNAL LINKS Calorie restriction Biology of Aging
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