What is oxidative stress?
Oxidative stress is an imbalance: your body produces more reactive oxygen compounds (free radicals) than its own defence systems can neutralise. This can damage cell components such as fats, proteins and DNA. A certain level of radicals is normal, though, and even necessary.
Oxidative stress explained simply
Every time your cells produce energy, reactive oxygen compounds are formed, known as ROS (reactive oxygen species) or free radicals. They are chemically very reactive and pull electrons from other molecules. The "rust on a car" comparison fits quite well: oxygen can attack material when nothing holds it back.
A whole defence system does exactly that. It includes enzymes made by the body, such as superoxide dismutase, and compounds from food that act as antioxidants. Oxidative stress is present when the balance tips towards the radicals.
What causes oxidative stress?
- normal metabolism, especially in the mitochondria
- UV radiation and air pollutants
- smoking and heavy alcohol consumption
- chronic inflammatory processes
- ageing: the body's defence systems weaken over the years
An important caveat: free radicals are not "bad" in themselves. The immune system uses them for defence, and cells use them as signalling molecules. The problem is a sustained excess.
How is oxidative stress measured?
Typical blood markers used in studies as an indication of oxidative stress.
| Marker | What it indicates |
|---|---|
| Marker Malondialdehyde (MDA) | What it indicates breakdown product of damaged fats (lipid peroxidation) |
| Marker Superoxide dismutase (SOD) | What it indicates activity of an enzyme the body makes to protect itself |
| Marker Glutathione | What it indicates one of the cell's most important radical scavengers |
| Marker Total antioxidant capacity | What it indicates combined value of protective compounds in the blood |
Oxidative stress and curcumin in studies
Curcumin is studied for two properties: in the test tube it can scavenge radicals itself, and studies have observed that it influences the body's own protective enzymes such as superoxide dismutase. In studies with osteoarthritis patients, markers of oxidative stress were measured together with inflammatory markers, and values had changed after several weeks of intake.
This is a laboratory finding, not proof of a health benefit in everyday life. Antioxidant supplements have shown mixed results overall in large trials, and lower blood markers do not automatically mean an effect on symptoms. In addition, how much curcumin actually reaches the blood depends heavily on bioavailability.
Common misconceptions
“Free radicals are always bad.” No. They are part of normal defence and signalling processes. Eliminating them completely would disturb the body more than protect it.
“The more antioxidants, the better.” That is not true either. High doses of isolated antioxidants have not consistently shown benefits in studies, and some investigations even point to unfavourable effects. Vegetables, fruit and spices supply a broad range of protective compounds in sensible amounts.
“Oxidative stress can be measured at home.” No. The markers are determined in the lab and mainly serve research.
Frequently asked questions
Can I influence oxidative stress through diet? A varied, plant-based diet supplies many compounds with antioxidant activity. What is mainly supported is the link between such a diet and general health, less so the effect of individual substances.
Does exercise cause oxidative stress? In the short term yes, since intense exertion increases radical formation. In the long term, though, regular exercise stimulates the body's own defence systems.
Is oxidative stress a diagnosis? No, it is a biochemical concept, not a disease.
Oxidative stress is not a disease but a biochemical concept. A balanced diet rich in vegetables, fruit and spices, regular exercise and not smoking are the well-supported levers. If you have health concerns, talk to your doctor.
