In recent times, several news articles have talked about the issue of eating iodized salt, and there have been many inquiries from hyperthyroid patients about the relationship between iodized salt and thyroid disease. Some people ask if eating iodized salt can cause hyperthyroidism? Is hyperthyroidism caused by eating iodized salt? Is hyperthyroidism caused by too much iodine in the body? And so on. These issues to talk about my understanding, not right, please readers criticize and correct. Iodine is a necessary trace element in the human body, the human thyroid gland needs iodine to synthesize thyroid hormones, which are sent to various organs and cells throughout the body to regulate metabolism, promote growth and development, and maintain physiological functions. If the source of iodine is lacking, the supply is insufficient, which will lead to the reduction of thyroid hormones and cause disease. On the contrary, too much “raw material”, thyroid hormone synthesis too fast “overproduction”, will occur hyperthyroidism “hyperthyroidism”. The relationship between the thyroid gland and iodine metabolism is extremely close. People take about 100~200 micrograms of iodine from food and water every day, and about 1/3 of it enters the thyroid gland, which contains 8000 micrograms of iodine, accounting for 90% of the iodine content in the whole body. Regional iodine deficiency (daily intake of iodine is less than 100 micrograms) or food containing too many anti-thyroid components, or due to digestive diseases that affect the absorption of iodine, as well as congenital lack of enzyme synthesis of thyroid hormones or deiodinase, so that the synthesis of the obstacle or iodine reuse is difficult to achieve, which will varying degrees of impact on the biosynthesis of thyroid hormones and lead to iodine-deficiency thyroid disorders, such as cretinism, macroglossia. On the contrary, if the daily intake of more than 800 micrograms per day for a long time, it will also lead to goiter and iodine hyperthyroidism, medically known as iodine hyperthyroidism, which is mainly caused by excessive iodine supplementation to increase the synthesis and release of thyroid hormones. Iodine hyperthyroidism is only one of many types of hyperthyroidism, not all hyperthyroidism is caused by excessive iodine intake. China is one of the world’s most serious iodine deficiency diseases, taking iodized salt is the best way to eliminate iodine deficiency, so China as early as 1950 to take iodized salt, at first only in Shaanxi, Hebei, Hunan and other minority areas. 1993 the State Council promulgated the salt iodization elimination of iodine deficiency hazards management regulations, the official legislation in the implementation of the whole population in the implementation of iodized salt. In 1996, Guangdong Province began to implement universal iodized salt. With the implementation of this policy, the iodine deficiency situation of our population has been rapidly improved, and surveys have shown that the rate of goiter among children in our province has dropped significantly. According to the latest news, the national assessment team recently conducted a detailed inspection of Guangdong’s work on eliminating iodine deficiency diseases and concluded that all indicators have reached the national target of achieving the stage of eliminating iodine deficiency diseases. With the gradual intensification and popularization of iodized salt for the whole population, the incidence of thyroid disorders in China has shown a general increasing trend. The health departments in the coastal areas of Guangdong and the Pearl River Delta coincidentally found an increase in the incidence of hyperthyroidism after iodization, which is not caused by iodine deficiency but by an increase in iodine intake. Although exact epidemiologic data are not yet available, feedback from internists across the country is consistent. Although there are many reasons for the increased incidence of hyperthyroidism, there is a relationship with the use of iodized salt. Several foreign epidemiologic surveys of tens to hundreds of thousands of people have shown that universal iodine supplementation can increase the incidence of hyperthyroidism. This has been reported in the United Kingdom, the United States, Italy, the Netherlands and other countries. Therefore, we believe that the consumption of iodized salt is one of the causes of the increased incidence of hyperthyroidism, especially in high iodine areas. However, this phenomenon is transient, peaking in 1-3 years and gradually returning to pre iodization levels within 3-10 years. Why does increased iodine intake cause hyperthyroidism? Animal experiments have proved that high iodine causes an increase in the weight of the thyroid gland, expansion of the follicular lumen of the thyroid gland, flattening of the follicular epithelial cells, reduction of mitochondria, decrease in the number of cells and intercellular capillaries, and an increase in thyroid hormones. Pathophysiology suggests that iodine-deficiency goiter occurs with increased compensatory thyroid-stimulating hormone (TSH) secretion, and that after iodine supplementation, excessive thyroid hormone synthesis results in hyperthyroidism due to the action of excess thyroid-stimulating hormone. Some people have potential defects in the thyroid gland (potential hyperthyroidism), due to iodine deficiency to reduce the synthesis of thyroid hormones and did not show, iodine supplementation, resulting in excessive synthesis of thyroid hormones and potential hyperthyroidism to show. In addition, the thyroid gland itself internal environment stabilization mechanism is impaired, due to the high concentration of iodine on the thyroid gland can not play its effect on the synthesis of thyroid hormone, so that the thyroid hormone synthesis is too much and cause hyperthyroidism. The objective phenomenon that excessive iodine intake will lead to an increase in the incidence of hyperthyroidism has attracted the great attention and concern of our administrative departments, medical personnel and the general public. It is reported that the relevant departments will plan to appropriately reduce the iodine concentration of iodized salt, and it is possible not to engage in a one-size-fits-all approach to the supply of non-iodized salt to residents in areas that are not iodine-deficient or have high iodine levels. This will have a positive effect on alleviating the incidence of hyperthyroidism. Hyperthyroidism has many causes, excessive iodine intake is only one of the triggers, all hyperthyroidism is attributed to the service iodized salt is not scientific. Hyperthyroidism can be divided into various types, iodine hyperthyroidism is one of them. The common feature of all types of hyperthyroidism is a syndrome of increased metabolic rate due to excess thyroid hormones. Hyperthyroidism patients may experience some conscious symptoms, such as panic, rapid heartbeat, fear of heat, excessive sweating, irritability, fatigue, weight loss, hyperphagia, increased bowel movements, etc. Some patients may also find that their necks are thickened and their eyes are protruding. If the above symptoms and signs occur, it is likely to suffer from hyperthyroidism, and should go to the hospital in time to do the relevant examination, in order to clarify the diagnosis and early treatment. There is no need to panic if you have hyperthyroidism. With the development of medical science today, this disease is completely curable. However, it is different from colds and flu, and can not be cured within a few days, there is a process. As long as you follow your physician’s instructions and take regular medication, it is not difficult to cure. Currently there are four commonly used treatments: internal medicine anti-hyperthyroidism medication; surgical treatment, radioactive iodine treatment and traditional Chinese medicine. The use of radioactive iodine-131 treatment is currently recognized as an effective method in the world. Former U.S. President George W. Bush, who suffered from hyperthyroidism, was treated with radioactive iodine-131 and achieved very good therapeutic effect, and he is still full of energy and active in the world political arena. At present, some countries in the West have included this in the preferred method. However, many people in China lack a comprehensive understanding of this, and even have some misconceptions or prejudices. Why is Iodine-131 treatment so effective? Because iodine is a necessary raw material in the process of thyroid hormone synthesis by the thyroid gland, radioactive iodine-131 and stable iodine have the same physiological and biochemical properties, so the thyroid tissue also has a high absorption and concentration capacity for radioactive iodine-131. Under normal circumstances, the concentration of iodine in the thyroid gland can reach 25 times of the plasma concentration, and the concentration of radioactive iodine-131 in patients with hyperthyroidism is even higher due to the increase in the speed and amount of synthesized thyroid hormones, which can reach 80~90%. The effective half-life of iodine-131 in the thyroid gland is 3.5-4.5 days on average. A large concentration of radioactive iodine-131 exposes the thyroid gland to radiation, which destroys part of the thyroid tissue and reduces the production of thyroid hormones, resulting in the relief or cure of hyperthyroidism. Iodine-131 is a kind of unstable radioactive radionuclide, in the process of decay, it can emit a kind of short-range β-rays, with an average of 1 millimeter and the longest length of 2.2 millimeters, therefore, it can not only destroy thyroid tissues, but also have little or no effect on the surrounding tissues and organs of the thyroid gland. This shows that radioactive iodine-131 treatment of hyperthyroidism is a safe and simple method. Compared with other methods of treating hyperthyroidism, radioactive iodine-131 treatment for hyperthyroidism has a wide range of applicability, simple method, safety and effectiveness, fewer medications, fewer complications, high rate of one-time cure, low recurrence rate, and low cost, and it can be the preferred method for most patients.