ABSTRACT

A number of oxidative stress biomarkers have been identified and measured in biological fluids. The complexity of the human antioxidant defence/oxidant system and their delicate balance renders it extremely difficult to estimate the oxidative stress status. An active debate exists on the effect of antioxidant supplementation on exercise-induced oxidative stress. Marked divergence and often contradiction among studies addressing the effect of antioxidant supplementation on exercise adaptation may be explained by a variety of factors. Oxidative stress represents a dynamic situation of balance between oxidants and antioxidants. The number of different antioxidants present in serum or other body fluids makes it difficult to measure how much each contributes separately. Vitamin D retains antioxidant properties and affects inflammatory and immunity processes, synthesis of proteins, cell growth and proliferation, and regulates the expression of over 1000 genes in a variety of tissues.