主题：碘缺乏病与碘盐 - 序章 -- 荷兰北极熊

也就是说碘过量也是有危害的

下面是我查到的

中文的Merck Manual

“碘 过 量

　　碘中毒是由于每日摄入量过大（400倍RDA）引起。有时可出现在生活在海边的人中。碘过量可导致甲状腺肿大，引起甲状腺功能亢进。”

注：每日营养建议摄入量（英语：Recommended Daily Allowance，RDA）

英文的Merck Manual，更具体些，但没有“400倍RDA”

“IODINE EXCESS

Excess consumption of iodine is uncommon. It usually results from taking iodine supplements to treat a prolonged iodine deficiency. Sometimes people who live near the sea consume too much iodine because they eat a lot of seafood and seaweed and drink water that is high in iodine, as is common in northern Japan.

Consuming too much usually does not affect thyroid function, but sometimes it does. It may cause the thyroid gland to become overactive and produce excess thyroid hormones (hyperthyroidism—see Hyperthyroidism), particularly in people who used to consume too little iodine. However, sometimes excess iodine can decrease production of thyroid hormones (causing hypothyroidism—see Hypothyroidism). As a result, the thyroid gland enlarges, forming a goiter. (Goiters can form when the thyroid gland is underactive or overactive.)

If people consume very large amounts of iodine, they may have a brassy taste in their mouth and produce more saliva. Iodine can irritate the digestive tract and cause a rash.”

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试着翻译一下

“碘过量

碘的过量摄入是不常见的。通常是食用碘补充剂治疗确诊的碘缺乏症时发生的。偶有海边居民因大量食用海产品及饮用水中富碘而造成碘摄入过量，常见于日本北部。

通常情况下过量摄入不影响甲状腺功能，但有时会造成甲状腺过度活跃，泌出过量甲状腺素（甲状腺功能亢进症 -- 见“甲状腺功能亢进症”词条），尤其是在既往碘摄入不足的人群中。尽管如此，有时过量的碘会减少甲状腺素的泌出。（造成甲状腺功能减退症 -- 见“甲状腺功能减退症”词条）。结果是甲状腺肿大，形成结节。（甲状腺功能减退或功能亢进皆可造成肿大结节）

如果摄入很大量的碘，口中会有铜味，并伴过量的口水。碘会腐蚀消化道，造成水肿。

”