Abstract
A few years ago, a hypothesis of oxidative stress caused byx overproduction and activity of reactive and free radical oxygen, nitrogen and chlorine species was formulated. Oxidative stress is supposed to be an initiating and stimulating factor of many serious diseases.
Therefore, food antioxidants are considered as means of prevention and suppression of oxidativelly conditioned illnesses. However, massive and uncontrolled use of antioxidant vitamins and another substances,, now widespread in the general public, raises doubts about effectiveness and health safety of such practices.
New knowledge arising from epidemiological and, particularty, from experimental studies show that excessive doses of antioxidants are ineffective and can be harmful. Surprisingly, reactive oxygen species play an essential role in the intracellular signal transduction and, in this sense, are unavoidable.