Micronutrients: oxidant/antioxidant status

Potentially damaging species (reactive oxygen, nitrogen and chlorine specie s) arise as by-products of metabolism and as physiological mediators and si gnalling molecules. Levels of these species are controlled by the antioxida nt defence system. Several components of this system are micronutrients (e. g. vitamins C and E) or are dependent upon dietary micronutrients (e.g. CuZ n and Mn superoxide dismutase). The antioxidant defences act as a coordinat ed system where deficiencies in one component may affect the efficiency of the others. Oxidative stress may be an important factor in infection if mic ronutrients are deficient.