Supplementation with antioxidants in the treatment of Graves' disease; the effect on glutathione peroxidase activity and concentration of selenium

Background: The effect of supplementation with a fixed combination of antioxidants (vitamins C and E, beta-carotene and selenium) was monitored on the speed of attaining euthyroidism in a group of patients with Graves' disease, treated with methimazole. Methods: The activity of glutathione peroxidase in whole blood and the concentrations of selenium, pituitary and thyroid hormones in serum were measured, prior to commencement of therapy and after 30 and 60 days. Results: Patients who received supplementation with antioxidants in addition to therapy with methimazole (Group A, n = 29) attained euthyroidism faster than the patients treated with only methimazole (Group B, it = 28). The concentration of selenium in the serum of patients in Group A increased significantly during treatment (p < 0.001), while there was no statistically significant change in the patients in Group B. The concentration of selenium in the serum between the groups differed statistically significantly 30 days (p < 0.05) and 60 days (p < 0.01) after the commencement of therapy. Activity of glutathione peroxidase in whole blood increased during treatment in both groups of patients. However, a statistically more significant increase occurred in Group A compared to Group B. 30 days after the commencement of therapy (p<0.01). Conclusion: The results of the study clearly indicate that supplementation with antioxidants in the treatment of Graves' disease is justified, particularly those containing selenium. (C) 2004 Elsevier B.V. All rights reserved.