Oxidation-reduction reaction (redox) represents the biochemical process fundamental for life. In aerobic organisms, oxygen is converted to water and ATP at the end of the respiratory chain. That provides the energy needed to maintain normal body function and metabolism. In redox reaction, oxygen is partially reduced to form superoxide, i.e. a stucture with unpaired electrons' number, also named "reactive oxygen species" (ROS). Normally, ROS production is balanced by some antioxidant substances (AOX), such as enzymes, some vitamins and several small-molecules that play important roles in antioxidant defense. On the contrary, ROS prevalence induces oxidative damage in some human proteins, lipidis, carbohydrates and DNA, responsible for cell's morbidity until death. Specifically, ROS. act in the pathogenesis of atherosclerosis, cancer, some brain diseases, such as Alzheimer's and Parkinson', obesity, insulin resistance, type 2 diabetes mellitus and others. ROS also prevail in human tissue with advancing age, favouring the healthy ageing. Thus, the redox reaction represents the "mother" of many among human diseases and healthy aging. At present, the giving of AOX to balance the ROS prevalence is uncertain if reduces their damages, even if long-term AOX-diet consumption, together moderate physical activity BMI reduction and reduction of food intake, is able to slow down the ROS injuries progressively increasing with advanced age. ©2010 Pharma Project Group srl.