Reactive Oxygen Species:
Key Drivers of Cellular Damage and Disease
Oxygen is vital for life, but its use in cells inevitably generates reactive oxygen and nitrogen species (RONS)—unstable molecules that readily react with surrounding structures. When their levels overwhelm the body’s antioxidant defenses, a condition called oxidative stress, they damage DNA, proteins, and lipids, undermining cell health and driving disease.
DNA Damage – ROS/RNS break nuclear and mitochondrial DNA strands, modify bases, and impair repair, leading to mutations, genomic instability, cancer, aging, and immune activation.
Protein Oxidation – ROS/RNS alter protein structure and function, causing side-chain oxidation, misfolding, enzyme inactivation, mitochondrial dysfunction, and ultimately cell death or immune responses.
ROS and RNS–induced damage is implicated in cancer, neurodegenerative diseases (Alzheimer’s, Parkinson’s, ALS), cardiovascular disease (atherosclerosis, stroke), chronic inflammatory and autoimmune disorders (COPD, rheumatoid arthritis, lupus), liver disease (NAFLD), diabetes complications, and mitochondrial or metabolic disorders. These arise from oxidative injury to DNA, proteins, and lipids that disrupts cell function, fuels inflammation, and drives cell death.
Sources of Free Radicals
Free radicals arise both inside the body and from the environment.
Internal (endogenous): They are byproducts of normal processes such as energy production in mitochondria, enzyme activity during metabolism and inflammation, and immune cells releasing radicals to fight infections.
External (exogenous): They are also triggered by outside factors like radiation, pollution, smoking, alcohol, processed foods, and certain drugs, all of which can raise oxidative stress.
How Free Radicals Damage the Body
When produced in excess, ROS/RNS attack vital cellular components, disrupting function and driving disease.
Lipid Peroxidation – ROS/RNS damage membrane lipids, generating toxic byproducts, destabilizing membranes, disrupting signaling, oxidizing LDL, and promoting inflammation and tissue injury.
