Iodine is an essential trace element for human and an antioxidant. It not only participates in the synthesis of thyroid hormone, but also plays a role in metabolic diseases. Previous studies mainly focused on the effect of iodine on thyroid diseases, but ignored the effect on metabolism. After the implementation of the universal salt iodization (USI) of China, the possible consequences of excessive iodine were emphasized while the harm of iodine deficiency was forgetten. The paper re-examines the effects of iodine nutrition on thyroid diseases and metabolism. Iodine deficiency can lead to an increased risk of iodine deficiency disorders and thyroid diseases, and increase prevalence of metabolic syndrome and its components. Moderate iodine excess is beneficial to metabolism, but it can increase the risk of hyperthyroidism and subclinical hypothyroidism. The average urinary iodine concentration in 100-299 μg/L is the appropriate iodine nutrition state. According to the present iodized content of salt in China, iodized salt is an economical and effective way to ensure adequate iodine nutrition.碘是人体必需的微量元素,也是一种抗氧化剂,其不仅参与甲状腺激素的合成,对代谢性疾病也有作用。既往研究主要强调碘对甲状腺疾病的影响,而忽略了对代谢的影响;我国实施普遍食盐加碘(USI)政策后,重点关注了碘过量可能导致的后果,而淡忘了碘缺乏的危害,本文重新审视碘营养对甲状腺疾病和代谢的影响。碘缺乏可导致碘缺乏病和甲状腺疾病的发生风险增加,还可导致代谢综合征及其组分患病率增加。适当的碘过量有益于代谢,但可增加甲状腺功能亢进症和亚临床甲状腺功能减退症的发生风险。平均尿碘浓度在100~299 μg/L为适宜的碘营养状态。根据我国目前的食盐加碘含量,食用加碘盐是保证适宜碘营养经济有效的方法。.