Ward J M, Ohshima M
Adv Exp Med Biol. 1986;206:529-42. doi: 10.1007/978-1-4613-1835-4_37.
Iodine is an essential nutrient for the normal growth and development of humans and animals and is necessary for normal metabolism and regulation of thyroid hormones. Iodine excess can produce thyrotoxicosis but not cancer. However, radioiodine is carcinogenic for the thyroid gland. Dietary iodine deficiency is associated with goiter in humans and animals. The goiter develops because of a feedback system between thyroid hormones, the pituitary gland, and the hypothalamus, and it regulates the synthesis and release of thyroid-stimulating hormone. Chronic hypersecretion of thyroid-stimulating hormone causes profound goiter (diffuse thyroid hyperplasia), which appears to be related to carcinogenesis. Chronic dietary iodine deficiency in rats leads to thyroid follicular adenomas by 12 months and follicular carcinomas by 18 months. An increased risk of thyroid cancer has been reported in humans with goiter and those living in some iodine-deficient areas of the world. In very recent animal studies, iodine deficiency, chemical goitrogens, and thyroid toxins have been shown to have potent tumor-promoting effects. In rats, iodine deficiency is a much more effective tumor promoter than it is a carcinogen, suggesting that a similar relationship may exist in human populations. These studies suggest that a major role of iodine is to prevent the formation of thyroid tumors in humans and animals.
碘是人类和动物正常生长发育所必需的营养素，对于正常新陈代谢和甲状腺激素调节至关重要。碘过量会导致甲状腺毒症，但不会引发癌症。然而，放射性碘对甲状腺具有致癌性。饮食中碘缺乏与人类和动物的甲状腺肿有关。甲状腺肿的发生是由于甲状腺激素、垂体和下丘脑之间的反馈系统，该系统调节促甲状腺激素的合成和释放。促甲状腺激素的慢性过度分泌会导致严重的甲状腺肿（弥漫性甲状腺增生），这似乎与致癌作用有关。大鼠长期饮食中碘缺乏会在12个月时导致甲状腺滤泡腺瘤，18个月时导致滤泡癌。据报道，患有甲状腺肿的人和生活在世界上一些缺碘地区的人患甲状腺癌的风险增加。在最近的动物研究中，碘缺乏、化学性甲状腺肿剂和甲状腺毒素已被证明具有强大的肿瘤促进作用。在大鼠中，碘缺乏作为肿瘤促进剂比作为致癌物更有效，这表明在人类群体中可能存在类似的关系。这些研究表明，碘的主要作用是预防人类和动物甲状腺肿瘤的形成。
