We have been hearing a lot about free radicals and antioxidants. What exactly are these two? And why all the attention focussed on them?  That’s because free radicals and antioxidants have a huge influence on our health.

What are free radicals?

Free radicals are molecules with an unpaired number of electrons. A free radical is a substance that interacts with other molecules either by taking an electron or by giving an electron. Usually a free radical takes an electron. When molecules are hit by free radicals and an electron is removed from their structure the molecules become weak and unstable (1).

How are free radicals formed?

Free radicals enter our body through food and through substances we breathe. Free radicals are produced when normal cell metabolism reactions take place in the body. They are also formed because of external sources such as pollution, cigarette smoke, radiation and medication. When there is an overload of free radicals because of internal or external sources and are not removed as and when they are formed, the free radicals accumulate in the body. This build-up of free radicals in the body is called oxidative stress (2).

Importance of free radical levels in the body

At low or moderate levels free radicals are not harmful in fact they exert beneficial effects on cellular responses and immune function. Free radical existence in the body to a certain extent is normal. These are produced while generating energy by breaking down macronutrients, carbohydrates, protein and fat. Immune system also produces free radical substances to tackle foreign bodies or debris in the body.

The problem starts when the content of free radicals becomes a lot in the body which leads to degenerative diseases. The exceedingly reactive radicals may start a chain reaction and the harmful effects occur when they react with cellular components such as DNA, proteins, fatty acids or the cell membrane (1).

Free radicals

Free-radical substances contain oxygen, for example

• Superoxide (O₂⁻)
• Hydrogen peroxide (H₂O₂)
• Hydroxyl radicals (OH⁻)

Harmful effects of free radicals

The accumulation of free radicals leads to oxidative stress. It is the main reason for the development of chronic and degenerative illnesses such as

• cancer
• autoimmune disorder
• aging
• cataract
• rheumatoid arthritis
• cardiovascular
• and neurodegenerative diseases (2)

What are antioxidants?

Our body has several mechanisms to combat oxidative stress by generating antioxidants. These may be naturally produced in the body or consumed the form foods and supplements which contain antioxidants. These antioxidants perform the role of “free radical scavengers”.

How do antioxidants function?

The term antioxidant means that these molecules help in inhibiting free radicals from taking electrons from other molecules. An antioxidant is a molecule capable of preventing oxidation. This may be done by the antioxidants by donating their own electrons to a free radical. Antioxidants are capable of remaining stable even after losing an electron to a free radical. Antioxidants are substances which help us to keep the free radicals from accumulating in the body. They stop the free radicals before they can damage vital components of cells.

Antioxidants in food

Antioxidants prevent the harmful damage caused by free radicals and they also repair the damage caused by free radicals. Antioxidants can enhance the immune function and reduce the risk of cancer and other degenerative diseases (2). Vitamins and minerals such as vitamin C and E, selenium, copper, iron, manganese, zinc and certain phytonutrients such as lycopene, lutein and zeaxanthin are capable of antioxidant activity.

References

1. Wildman, R. (2009) The Nutritionist-Food, Nutrition, and Optimal Health. Routledge, Taylor and Francis Group. Second Edition. New York and London

2. Pham-Huy, L. A., He, H. and Pham-Huy, C. (2008) Free radicals, antioxidants in disease and health, International journal of biomedical science: IJBS. Vol. 4(2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3614697/