Free-radical theory of aging

Called the theory of free radicals, and free radical theory (English Free Radical Theory of Aging, FRTA ) is an explanatory model for aging in all organisms.

Description

The theory of free radicals says that so-called free radicals are produced in cells as a result of the metabolic processes of molecular oxygen. This short-lived molecular fragments, such as the hydroxyl radical • OH, play an important role in a number of cell biological processes and are detectable by various analytical methods. The U.S. biogerontologist Denham Harman introduced in 1956, the thesis that these free radicals are the cause of the aging process. With its release free radicals for the function of the cell damage important molecules such as DNA, RNA and a variety of proteins and lipids. This leads to the thesis, to an ever- growing accumulation of damaged cellular components, which in turn causes the complex aging process. The cells themselves are able to produce substances that can render free radicals harmless by these react with these " free radical scavengers " or be decomposed catalytically over them. These include, for example, the urates or the catalase enzyme. Also through the food antioxidants such as ascorbic acid, β -carotene, polyphenols, flavonoids, are added, capable of reacting in the cells with the free radicals. Nonetheless example, can be detected in the urine degradation products that arise as a result of damage to the DNA or lipids.

Reception

At the beginning of the theory of free radicals has been rejected by many gerontologists and partly considered as para scientifically. In the following period could be explained by this theory, but some scientific findings. It also serves as an explanatory model for the emergence of a number of diseases such as cancer, atherosclerosis, diabetes mellitus and Alzheimer's disease.

Reduced food intake is less oxidative stress to the cells, which in turn leads to a smaller amount of free radicals and thus less damage within the cell. In effect, calorie restriction in various model organisms, a significant increase in life expectancy. Supplementation of antioxidants results in a number of species in an increase in average survival time when these substances are administered very early. However, the maximum service life could not be increased.

A number of other experiments provides the theory of free radicals conflicting results. Thus, the working group around the German internist Michael Ristow show that free radicals are necessary to set the Mitohormesis in motion, whereby the cell achieves an increased defense capacity against free radicals. Contrast, antioxidants prevent the Mitohormesis.

The mitochondrial theory of aging has been developed from the theory of free radicals out.

Free-radical theory of aging

Description

Reception

Further Reading