The TL;DR
Your body is constantly burning fuel for energy. Like a car engine, this produces exhaust fumes called Reactive Oxygen Species (ROS) or free radicals. When these free radicals overwhelm your body’s antioxidant defenses, you get Oxidative Stress. This essentially “rusts” your body from the inside out, damaging DNA, cell membranes, and mitochondria.
Accessibility Level
Level 1 (Foundation): Understanding this concept explains why we eat vegetables (antioxidants) and why we exercise (to build better engines).
The Science of Rust
The Double-Edged Sword
We used to think ROS were universally bad. We now know they are critical signaling molecules.
- Too Much ROS: Damages DNA, creates senescent cells, drives inflammation.
- Too Little ROS: The body fails to signal repair mechanisms. This is why taking high-dose antioxidant supplements (Vitamin C/E) after exercise can actually block the benefits of the workout.
Sources of Stress
- Internal: Leaky mitochondria (the biggest source), chronic inflammation.
- External: UV radiation, pollution, cigarette smoke, charred meats (AGEs).
The Consequence: Genomic Instability
When ROS attack DNA, they cause strand breaks. If the repair crew (PARP, Sirtuins) cannot keep up, these mutations accumulate, leading to cancer and cellular dysfunction.
Evidence Matrix
| Source | Verdict | Notes |
|---|---|---|
| Denham Harman | Theory Originator | Proposed the “Free Radical Theory of Aging” in the 1950s. |
| Modern View | Nuanced | It’s not just “damage”; it’s a disruption of redox signaling. |
| Clinical Trials | Warning | Large trials show high-dose antioxidant supplements often increase mortality (e.g., Vitamin E). |
How to Optimize (Redox Balance)
The goal is Hormesis—exposure to just enough stress to trigger your own defenses.
- Endogenous Defense: The antioxidants your body makes (Glutathione, SOD) are 1000x more powerful than any pill.
- Sulforaphane: Found in broccoli sprouts, it activates the Nrf2 pathway, turning on your antioxidant genes.
- Exercise: A temporary spike in oxidative stress that teaches the body to build stronger defenses.
- Avoid Toxins: Stop smoking, limit alcohol, and avoid burning your food.
References
Harman, D. (1956). Aging: a theory based on free radical and radiation chemistry. Journal of Gerontology.
Sies, H. (2015). Oxidative stress: a concept in redox biology and medicine. Redox Biology, 4, 180-183.
Ristow, M., et al. (2009). Antioxidants prevent health-promoting effects of physical exercise in humans. PNAS.