Free radicals are unstable atoms which have the ability to damage cells, causing illness and responsible for aging.
Free radicals are associated with aging and a host of diseases, but there is very limited research on its role in human health, or how to prevent them from making people ill.
These Free radicals may be developed by natural human physiological processes as well as from the environment.
It can be the result of various factors such as stress, diet, alcohol, smoking, exercise, inflammation, drugs or exposure to sunlight or air pollutants.
While there are various types of free radicals which can be formed, the most common in aerobic organisms (oxygen breathing) are oxygen free radicals, often termed as Reactive Oxygen Species (ROS), which include Superoxides, hydrogen peroxide, hydroxyl anions, and singlet oxygen.
What is a Free Radical?
Understanding free radicals need some knowledge of chemistry.
A free radical is an atom or the group of atoms which has an unpaired electron and is therefore unstable and highly reactive.
This atom’s chemical behavior is determined by the number of electrons present in its outermost shell.
When the outermost shell is full of electrons, the atom is stable and tends not to participate in chemical reactions.
When, however, the outermost shell is not full with electrons, the atom is unstable so it will try and stabilize itself through either gaining or losing an electron to either fill or empty its outermost shell.
Or it will share its electrons through bonding with another atom which is also looking to complete its outer shell.
This thing is not uncommon for an atom to complete its outer shell through sharing an electron with another atom and forming a bond.
Free radicals develop when one of these types of weak bonds between these electrons is broken and an uneven number of electrons remain.
This means the electron is still unpaired and making it chemically reactive. It will now begin to try and steal an electron from a neighboring molecule to stabilize itself.
Once a free radical forms and it gets success in gaining another electron from a neighbor molecule, it leaves its victim short an electron and has now made this new molecule also a free radical, which will, in turn, try and steal another electron as well.
The result of this process is what we call a free radical cascade, an enormous chain reaction of free radicals which quickly wreaks havoc on living tissue.
It is assumed that the chain reaction can trigger 6.023 x 1021 billion molecules to react every second!
How Do Free Radicals Form?
Free radicals may form spontaneously or they may be the result of various factors such as exposure to heat, stress, diet, alcohol, smoking, exercise, inflammation, drugs, light or something in the environment. Sometimes the body’s own immune system develops them on purpose to neutralize viruses and bacteria.
Unfortunately, oxygen is most susceptible to free radical formation, and with aerobic organisms, this can be lethal.
Oxygen free radicals are involved in the overall aging process and are responsible for photoaging, cancer, and inflammation in the skin. Oxygen free radicals can cause lipid peroxidation, which results in damage to cell membranes and this leads to premature aging, skin cancer, and cell death.
How do free radicals damage the body?
As per the free radical theory of aging, free radicals break cells down over time.
Upon age, the human body loses its ability to fight the effects of free radicals. This leads to the formation of more free radicals, more oxidative stress, and finally more damage to cells, which results in degenerative processes, as well as “normal” aging.
Various studies and theories have linked oxidative stress due to free radicals, can leads to:
- Central nervous system diseases like Alzheimer’s and other dementias
- Cardiovascular disease because of clogged arteries
- Autoimmune and inflammatory disorders like rheumatoid arthritis and cancer
- Cataracts or age-related vision decline
- Age-related changes in appearance like loss of skin elasticity, wrinkles, hair loss, graying hair, and changes in hair texture
- Genetic degenerative diseases, including Huntington’s disease or Parkinson’s
The free radical theory of aging is relatively new, However many studies support it. Studies on rats showed significant increases in free radicals as the rats aged. These changes end up with age-related declines in health.
Over time, scientists have tweaked the free radical theory of aging to focus on the mitochondria, which are tiny organelles in cells that process nutrients to power the cell.
Research on rats suggests that free radicals formed in the mitochondria damage the substances that the cell needs to function properly. This damage can causes mutations that produce the number of free radicals, thus accelerating the process can damage the cell.
This theory helps explain the aging, as aging accelerates over time. Gradually but the increasingly rapid buildup of free radicals explains why even healthy bodies age and deteriorate over time.
Free radical theories of aging and disease can help explain why few people age more slowly than others.
Although free radicals are formed naturally in the body, lifestyle factors can also accelerate their production, Such as:
- Exposure to toxic chemicals, like pesticides and air pollution
- Fried foods
These lifestyle factors are also responsible for diseases like cancer and cardiovascular disease. So, oxidative stress may be a reason why exposure to such substances causes disease.
Antioxidants and free radicals
It is impossible to watch television without seeing at least one commercial advertisement that promises to fight Aging with antioxidants. Antioxidants are molecules which prevent the oxidation of other molecules.
Antioxidants are one type of chemicals which lessen or prevent the effects of free radicals on the body.
They donate an electron to free radicals, so by this they reducing their reactivity. What makes antioxidants unique and important is that they can donate an electron without becoming reactive free radicals themselves.
No single antioxidant can combat the effects of each free radical. Just as free radicals have different effects in different parts of the body, every antioxidant behaves differently because of its chemical properties.
In some contexts, however, some antioxidants may become pro-oxidants that grab electrons from other molecules, creating chemical instability causes oxidative stress.
Antioxidant foods and supplements: Do they really work?
Numbers of chemicals can act as antioxidants. Vitamins C, Vitamin E, beta-carotene, glutathione, and plant estrogens called phytoestrogens are among the many antioxidants which can slow down the effects of free radicals.
Many foods are a rich source of antioxidants. Citrus fruits, Berries, and many other fruits are rich in vitamin C, while carrots contain a high level of beta-carotene content. The soy available in soybeans and some meat substitutes are high in phytoestrogens.
Due to High availability of antioxidants in such foods, some health experts to advise antioxidant-rich diets. The antioxidant theory of aging also led many companies to increase sales of antioxidant supplements.
Research on antioxidants is very confusing. Most research shows negligible or no benefits. A 2010 study that looked at antioxidant supplementation for the prevention or treatment of prostate cancer found no benefits.
A 2012 study found that antioxidants do not lower the risk of disease like lung cancer. In fact, for people already at more risk of cancer, for example, smokers, antioxidants slightly elevated the risk of cancer.
Some studies have even found that supplementation with antioxidants is harmful to the body, particularly if people take more than the recommended daily allowance (RDA).
A 2013 study found that higher dose of beta-carotene or vitamin E significantly increased the risk of dying.
Certain studies have found benefits linked with antioxidant use, but the results have been modest. A study of 2007, for instance, found that long-term consumption of beta-carotene could modestly decrease the risk of age-related problems with thinking.
What we do not know
Studies show that antioxidants cannot cure the harmful effects of free radicals – at least not when antioxidants consumed from artificial sources.
It is also possible that free radicals are an early sign of cells already fighting disease, or that free radical production is inevitable with age. Without enough data, it is nearly impossible to understand the problem of free radicals fully.
People interested in fighting free radical-related aging must avoid common sources of free radicals, includes pollution and fried food. They should also consume healthful and balanced diet without worrying about supplementing with antioxidants.