Antioxidants neutralize free radicals as the natural by-product of normal cell processes. Free radicals are molecules with incomplete electron shells which make them more chemically reactive than those with complete electron shells. Exposure to various environmental factors, including tobacco smoke and radiation, can also lead to free radical formation. In humans, the most common form of free radicals is oxygen. When an oxygen molecule (O2) becomes electrically charged or "radicalized" it tries to steal electrons from other molecules, causing damage to the DNA and other molecules. Over time, such damage may become irreversible and lead to disease including cancer. Antioxidants are often described as "mopping up" free radicals, meaning they neutralize the electrical charge and prevent the free radical from taking electrons from other molecules.
Study to determine oxygen free radical activity in neonates, and examine infection risk and compare the degree of oxidant stress in newborns treated with different oxygen concentrations.
Plasma selenium levels in neonates with high infection risk (IR) were significantly lower than in healthy neonates. Comparative study of selenium in preterm, term and young infants showed age-related increases and differences were significant. Plasma selenium values were lower when oxygen therapy was administered. Vitamin E levels were significantly decreased in IR compared with healthy newborns.
The results suggest that selenium and vitamin E deficiencies predispose to neonatal infection and that supplementary oxygen contributes significantly to decreasing the antioxidant defense system.