What are free radicals? What role do they play in our natural defense systems? 


In recent years, you might have frequently read in health journals about “free radicals” and how damaging they are to your body. But what are really these “free radicals”? And when and why are they dangerous?

Free radicals are in fact two-faced: they can be beneficial as well as harmful to your body. They are normally produced by the body for specific and vital purposes such as energy production and immune defense. However, when in excess, they are destructive.

What are free radicals? 

When your body is exposed to unhealthy environmental factors, some of its components lose one of their paired electrons on their superficial layer. It is called oxidation. It is similar to what happens to an apple when you peel off its skin: its flesh is oxidized, turning brown due to the oxidation phenomenon. When a normal molecule loses one electron, it is oxidized and becomes a free radical.

free radical

Free radicals are molecules that have unpaired electrons on their orbit. As such, they are very unstable, highly reactive, and potentially dangerous to the body: they seek to recover their missing electron by oxidizing biomolecules such as proteins, lipids, carbohydrates, and DNA. Free radicals may cause irreversible damage to the normal structural and metabolic functions of these substances. However, free radicals are also useful to the body. They are produced by our white blood cells to destroy invading pathogens such as bacteria, viruses or parasites, and kill cancer cells.

Free radical Oxidation

How are free radicals formed? 

Free radicals are formed in a number of ways. In the body, oxygen radicals, as well as hydroxyl radicals, are generated during energy production. Free radicals are also formed from exposure to electromagnetic fields, UV rays, x- rays, ultrasound waves and irradiation. Chemicals, drugs, or other elements from the environment, including cigarette smoke and other forms of air pollution, can also lead to free radical formation. Once formed, these free radicals initiate their own reactions and the molecules they react with are in turn converted into free radicals. With new free radicals being formed, a chain reaction is produced which further increases their potentially harmful effects in the body.

How can free radicals induce damage?

Free radicals can attack the membranes that surround and protect our body cells. Destabilizing the cell membranes induces faster cell and tissue deterioration.

Free radicals can damage the body proteins.

The oxidation of the body proteins might cause biological problems as it destabilizes and modifies the protein structure, and destroys their metabolic functions in the body.

Free radicals can damage the DNA of our cells.
Hydroxyl radicals can also attack DNA during exposure to electromagnetic waves, UV rays, and x-rays. When the DNA structure of individuals is altered by such free radical interaction, mutations might be passed on to their offspring.

Free radical-induced Injury

Free radicals increase the body resistance against diseases by destroying invading organisms. However, when produced in excess and not destroyed by our antioxidative system, free radicals may damage different body components, resulting in lesions that lead to a real syndrome, i.e. oxidative stress. Many studies in the past twenty years have shown the role of free radicals and the evidence of oxidative stress in nearly all diseases.

Free radical-induced diseases can be classified as follows:

Free Radicals as the main factor of disease:
– Cataract, cancer,
– Quick aging, Acute Respiratory Distress Syndrome (ARDS),
– Pulmonary edema, ALS.

Free Radicals as one factor of disease:
– Diabetes,
– Alzheimer’s, Parkinson’s diseases,
– Inflammatory diseases,
– Cardiovascular diseases.

Free Radical as an increasing factor of disease:
– Acute inflammations,
– Infections.




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