{'fraction_non_alphanumeric': 0.024046001045478306, 'fraction_numerical': 0.00575013068478829, 'mean_word_length': 5.577319587628866, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The role of iodine vs selenium on the rising trend of autoimmune thyroiditis in iodine sufficient countries

Autoimmune thyroiditis (AT) or Hashimoto’s thyroiditis is an organ-specific autoimmune disease, characterized by infiltration of the thyroid gland by activated immune cells, leading to gradual destruction of thyroid cells, and eventually to hypothyroidism. In this condition, the activated T lymphocytes induce apoptosis of thyroid cells by the secretion of proinflammatory cytokines, whereas B lymphocytes produce antibodies against the thyroid autoantigens, thyroid peroxidase (TPO) , and/or thyroglobulin (Tg).1,2 Accumulating evidence suggests that the incidence of AT is increasing in iodinesufficient countries. Especially, in formerly iodine deficient areas, the elimination of iodine insufficiency, following iodine prophylaxis programs or silent iodine prophylaxis, has been followed by a rise in the prevalence of AT.3‒5 Iodine is an essential nutrient for thyroid function. It combines with thyroglobulin to produce the thyroid hormones thyroxine (T4) and tri-iodothyronine (T3) and so, normal thyroid function is dependent on adequate iodine intake.6 On the other hand, selenium is a mineral that is found in high concentrations in the thyroid, and the selenoproteins in the gland are involved in antioxidant defense. Selenium appears to protect thyroid cells from oxidative damage, incurred by exposure to hydrogen peroxide (H2O2), a byproduct during thyroid hormone synthesis from iodine.7,8 In the present opinion article, evidence is provided in support of the hypothesis that an optimal balance of iodine to selenium supply to the thyroid gland is important for maintaining a normal thyroid function. Loss of such balance in favor of iodine exerts a triggering effect on the induction of thyroid autoimmunity. The role of iodine and the balancing effect of selenium on thyroid physiology