The etiology of thyroid gland is complicated, which can usually be divided into six types: 1. Endemic goiter mostly occurs in iodine-deficient areas; 2. Physiological goiter is more common in adolescence, pregnancy and lactation; 3. Iodine goiter; 4. hyperthyroidism; 5. Thyroiditis; 6. Thyroid lump.

It is very beneficial for the first two patients to eat more iodine-rich food, but the latter four patients eat iodine-rich food, which is not only useless, but also makes their condition worse or brings trouble to diagnosis and treatment.

There are more patients with iodine goiter in coastal and inland low-lying saline-alkali land. This is due to long-term excessive consumption of iodine-rich seafood or excessive iodine content in drinking water. If we continue to give these "thick neck" foods rich in iodine, it will undoubtedly aggravate the condition and even lead to hyperthyroidism.

The thyroid iodine uptake capacity of hyperthyroidism patients is 10 times that of normal people. A large amount of iodine can temporarily inhibit thyroxine in a short time, but iodine is the raw material of thyroxine after all. Continuous intake of excessive iodine for more than half a month will also cause the increase of thyroid hormone, which will further aggravate the symptoms of hyperthyroidism.