Oxidative stress
An imbalance between the production of free radicals and the body's antioxidant capacity, causing cell damage involved in ageing and many diseases.
Oxidative stress occurs when free radicals (produced by metabolism, pollution, tobacco, UV, stress) exceed the body’s antioxidant defences. Free radicals then damage DNA, proteins and lipid membranes.
It is implicated in ageing, atherosclerosis, cancers, neurodegenerative diseases and diabetes.
The original angle (balance, not eradication): the common mistake is to believe you must eliminate all oxidative stress with antioxidants. But moderate oxidative stress is a useful signal (see hormesis): it triggers natural defences and beneficial adaptations (to exercise in particular).
The body has its own antioxidants (far more powerful than those from food): glutathione, superoxide dismutase (SOD) and catalase. These systems are inducible: they get stronger when they are moderately challenged (exercise, mild stress, certain plant compounds such as the sulforaphane in broccoli, which activates the Nrf2 pathway).
The supplement paradox: bombarding the body with external antioxidants (mega-doses of vitamin C/E) can put its own defences to sleep and block adaptation signals. Studies on high-dose antioxidant supplements are disappointing, even negative.
The real anti-oxidative-stress strategy:
- Reduce the sources of free radicals (tobacco, ultra-processed foods, excess alcohol, sedentary living)
- Feed the defences with whole foods (cruciferous vegetables, berries, spices, green tea) that activate the body’s own antioxidant systems
- Move (exercise strengthens the defences despite, or thanks to, the temporary production of radicals)
- Sleep well (sleep is restorative)