Oxidative stress refers to a pathological state that arises from the damage caused by free radicals (collectively known of as reactive oxygen species, ROS) when they interact with molecules in the body.

These free radicals can damage any component of the cell such as the DNA, the proteins and the lipids and give rise to cancer and various other disease states such as heart disease and neurodegenerative disorders.

Free radicals

The oxygen molecule is highly reactive and quite toxic. Examples of free radicals include:

• Singlet oxygen
• Perhydroxyl
• Hydroxyl radical
• Superoxide anion
• Nitric oxide

Free radicals are essentially molecules that contain an unpaired electron. This means they are highly unstable and seek out and capture electrons from molecules in healthy cells to stabilize themselves. This leaves the molecules they stole an electron from destabilized and those molecules then need to seek out stabilization, leading to a chain of thousands of free radical reactions.

Antioxidants counteract the actions of free radicals by donating an electron without destabilizing their structure. Through this stabilization, antioxidants prevent further damage to healthy cells.

Oxidative stress occurs when free radicals are too numerous for antioxidants to adequately neutralize. Environmental pollutants, toxins, medications, infections, poor diet and radiation are all factors that contribute to the likelihood of this free radical/antioxidant imbalance.

Further Reading

• All Oxidative Stress Content
• What is Oxidative Stress?
• Oxidative Stress and Antioxidants
• Oxidative Stress Effects
• Oxidative Stress, Glycogen Depletion and Lifespan

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.