The effect of antioxidant supplementation on superoxide dismutase activity, Cu and Zn levels, and total antioxidant status in erythrocytes of patients with Graves' disease.

The effects of supplementation with a fixed combination of antioxidants (vitamins C and E, beta-carotene and selenium) on superoxide dismutase activity, copper and zinc concentrations, and total antioxidant status were monitored in erythrocytes derived from a group of patients with Graves' disease treated with methimazole, with respect to the rate of achieving euthyroidism. Thyroid-stimulating hormone (TSH), thyroid hormones and the above-mentioned parameters were measured before therapy, and on days 30 and 60 after therapy initiation. The patients receiving antioxidant supplementation along with methimazole therapy (group A, n = 27) achieved euthyroidism at a faster rate than those treated with methimazole alone (group B, n = 28). The activity of superoxide dismutase decreased significantly in both patient groups during the treatment; however, there was no significant difference between the groups. There was no significant change in the erythrocyte concentration of copper, whereas the zinc concentration and total antioxidant status showed significant between-group differences. The study results clearly show that antioxidant supplementation in the treatment of Graves' disease is justified, while zinc and total antioxidant status in erythrocytes seem to be sensitive indicators of the efficacy of supplemental therapy.