free radical theory

free radical theory

A theory which posits that the changes seen in ageing cells and organisms are due to an accumulation of molecules damaged by free radicals. The host cell’s defences against free radical damage include glutathione peroxidase, alpha-tocopherol (vitamin E) and superoxide dismutase; intracellular superoxide levels are believed to correlate well with lifespan.
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"There's a theory -- the free radical theory of aging -- that's been around for a long time that says when we oxidize our food to produce energy there's a number of free radicals that are produced that are side products of that action and many of these are quite toxic," said Beelman.
ME-3's Antioxidant Activity: In 1956, Denham Harmon, MD, introduced the Free Radical Theory of Aging in an article titled "Aging: a theory based on free radical and radiation chemistry." (9) Although the idea was initially met with skepticism, free radicals and free radical damage are now recognized as one of the primary causes of the aging process.
One theory put forth is the "free radical theory of aging." This theory purports that the firing rate of the neurons in the canals of the vestibular system exert a heavy metabolic load, a damaging cascade that could lead to oxidative stress (free radicals) and to dysfunctional central and/or peripheral function.
Ph.D., in Free Radical Theory of Aging argued that free radical damage was the culprit behind aging in all living creatures.
He developed the "Free Radical Theory of Aging" in 1954.
Since the conceiving of free radical theory by Denham Harman in the 1950s people gradually realized that oxygen free radicals produced during normal respiration would cause cumulative damage which would eventually lead to organismal loss of functionality and ultimately death.
"People believe that free radicals are damaging and cause aging, but the so-called 'free radical theory of aging' is incorrect," says Siegfried Hekimi, a professor in McGill's Department of Biology and senior author of the study.
The free radical theory of aging provides an attractive mechanistic approach to explain molecular changes in DNA, lipids, and proteins associated with the aging process [2].
Harman proposed the free radical theory of aging in the 1950s, expanding to implicate mitochondrial production of reactive oxygen species in the 1970s [2].
One of the most widely accepted theories proposed to explain ageing is the free radical theory, according to which oxygen-derived free radicals cause age-related impairment through oxidative damage to biomolecules, with mitochondria being the main target of free radical attack.
Dr Gems said: "The fact is that we don't understand much about the fundamental mechanisms of ageing - the free radical theory has filled a knowledge vacuum for over 50 years now, but it doesn't stand up to the evidence.
Though phenomenal literature and huge theories of ageing are put forward, the most recent and highly accepted theory is "Free Radical Theory of Ageing" conceived by Harman.[1] In the free radical theory of aging, there is some imbalance between production and scavenging mechanisms of free radicals.[2] The free radical theory of aging proposes that reactive oxygen species (ROS) cause oxidative damage over the lifetime of the subject which is critical in determining the life span.[3] It is the cumulative and potentially increasing amount of accumulated damage that accounts for the dysfunctions and pathologies seen in normal aging.