Free radicals theory

There is a theory known as Free Radical Theory which states that the living organism age due to accumulation of free radical damage. This continues for a long time. A free radical can be defined as a particular atom which has a single unpaired electron present in its outermost shell. Most of the free radicals that are biologically active are highly reactive and some like melanin are not reactive at all.

Biological damage is often linked to free radical damage. It is due to the process of oxidative damage. Anti-oxidants are somewhat like oxidative damage inhibitors which pacify the free radicals.

The free radical theory includes free radicals like superoxide(O2), oxidative damage also occurs from other reactive oxygen species like hydroxyl and peroxide ions; H2O2 and OH.

This theory of free radical aging was first proposed by Denham Harman in the mid 1950s. In the 1970s the theory was however extended to mitochondria production of the reactive oxygen species.

There are model organisms where the process of free radical Theory resulting in oxidative reaction helps extend lifespan of Drosophila and yeast.

In mice the life span of the animal decreases with the increase in oxidative reaction.

Reducing oxidative reaction levels may be successful in increasing the lifespan of organisms but it cannot be established as of now.

The process of free radical damage can be associated with many physical disorders and diseases like diabetes, Alzheimer’s disease, cancers, atherosclerosis, and arthritis. Processes like apoptosis, phagocytocis and inflammation can be linked to the process of free radical damage.

Apoptosis is a way of the body in which cells kill themselves. It is a way of controlling them; this process releases free radicals into the human body.

Redox factors are suspected of playing a greater role I cell death processes such as necrosis.

The relationship between ageing and free radicals has been drawn closely from the links between diseases and free radicals. The hypothesis states that the ageing process is a process involving the body’s reaction with the free radicals. Cumulative factors including degenerative diseases result in the process of ageing and the reaction of free radicals are one of them. The strong hypotheses are a bit controversial and are undergoing further investigation. Such results would prove the correct hypotheses.


There mutant strains of a roundworm Caenorhabditis elegans show a uniform trait. The ones which are more prone to free radical damage have lesser lifespan compared to the ones which are more prone to free radical damage.

Drosophilae having mutations in the genes owing to the reactive oxygen atoms present and this dramatically decreases the life span of these organisms. It also has susceptibility to oxidative reactions, partial male and female sterility and physical traits like deformed wings and abdomen.

Genetic mutations generally increase the effects of oxidative reduction in molecules and reduction in such processes generally enhances the lifespan of the organisms. But there sis very limited proof to establish this idea.

Consumption of high levels of various antioxidants may increase the lifespan of individuals or organisms but this trait is not very consistently observed in mice.

Phenybutylnitrone (PBN) is a particular compound which has shown to extend human lifespan by as much as about 10 percent. This has never been simulated in a laboratory.

Anti-oxidant supplementation has not shown any remarkable expansion in the lifespan of an individual.

Calorie restriction

A severe restriction in the calorie consumption has shown the decrease in the oxidative reactions possibly through promoting mitohormesis.
diet illustration

Calorie reduction along with the reduction in the frequency of meals has shown an enhancement in the life span of rodents. This process actually decreases the frequency of diseases and the life span was increased by as much as about 30-40 percent.

Dr Roy Walford was one of the most prominent scientists who advocated the use of caloric restriction methods.

Anti-oxidant therapy

The free radical theory believes that the consumption of antioxidants like Vitamin E, Vitamin C, and Vitamin B along with Superoxide Dismutase gradually slows down the process of ageing. It prevents the oxidative reaction of the molecules from the free radicals. High intake of fruits and vegetables in the diet provides more anti-oxidants into the body.

There are some results which say that anti-oxidation therapy has no effect on the process of aging. It may even accelerate the process of aging.

A recent study also says that a high consumption of fruits and vegetables also has no effect on the body as to decrease the incidence of cancers. It can make a more sensitive environment for the oxidative reactions.