The iodine in iodized salt used to be added as potassium iodide, but now it is added as potassium iodate. Adding iodized salt to food can replenish iodine, a micronutrient needed by the human body. Physiologically, two-thirds of the iodine in the human body is found in the thyroid gland, which controls metabolism, so an insufficient supply of iodine may cause problems such as slow mental response, fatness, and lack of vitality. However, iodine can be obtained from foods other than salt. Iodine supplementation is a long term effective process, excess iodine will cause hyperthyroidism, hypothyroidism, thyroiditis, thyroid cancer and other diseases, in recent years, the probability of thyroid cancer in China is slowly growing. Improvement of living standards, a few times a month to eat seafood is commonplace, and seafood containing iodine content may be equivalent to our daily intake of iodine a few times, often this one-time intake, is an important reason for excessive intake of iodine. Therefore, controlling iodine intake is particularly important. First of all, is to change the habit of heavy mouth, now we consume mostly iodized salt, eat more salt iodine intake is also more. Secondly, is to reduce the consumption of iodine-containing seafood intake, such as seaweed, kelp, seafood, etc., often consumed will invariably increase the amount of iodine intake in a day, bringing harm to the body.