RESUMEN
To determine whether the antioxidant defenses might be altered, plasma antioxidant concentration was evaluated in thirty-five children with giardiasis and/or amoebiasis and ten healthy control subjects. It was found that there was a significant decrease of superoxide dismutase activity in the infected children than the control and catalase enzyme was with no significant difference, while lipid peroxidation showed a highly significant elevation in the infected group. The study gave a new insight about the alteration of the circulating antioxidant concentration in the infected children and that their endogenous antioxidant defenses were not completely effective to diminish the oxidative damage, so that the beneficial effect of dietary antioxidants was particularly important in diminishing the cumulative effects of oxidative damage