Oxygen is essential for living organisms as it allows the production of energy from organic matter. Paradoxically, oxygen can also be cause harm because other processes, such as cellular respiration or defence mechanisms continually produce very reactive oxygen species, among which the so-called free radicals, all displaying highly oxidative properties that are considered to be toxic for the organism.
Oxidative stress arises from disequilibrium when excessive amounts of free radicals are generated which can no more be neutralised by the organism and thus, accumulate. Oxidative stress over a long period of time may trigger many pathologies ranging from cardiovascular diseases to cancer via chronic infectious and inflammatory diseases as well as neurodegenerative diseases. Moreover, numerous scientific studies suspect the oxidative stress to be the driving force of ageing.
Some examples of activities or states that lead to oxidative stress are:
- Intense physical activity or high performance sport activities
- Nutritional deficiencies or disequilibrium
- Tobacco or excessive alcohol consumption
- Chronic fatigue
- Psychic or intellectual stress
- Chronic or inflammatory diseases
- Treatments such as chemotherapy, radiotherapy, oral contraception
- Long-term exposure to pollution, UV radiation or infectious agents.
The correlation between the level of oxidative stress and the health status of a patient has been proven, but it was also revealed that possibilities exist to normalise or to optimise the health status related to oxidative stress in 80 to 90 % of all cases, independently of the clinical context or the patient's age.