How does iodine protect against radiation?

Radioactive substance iodine-13 1 has a half-life of 8 days, which is quite harmful to human health. It will accumulate on the thyroid gland and be quickly absorbed by the human body, leading to cancer and hereditary diseases. If concentrated potassium iodide is ingested in time after a nuclear accident, the radiation of the thyroid gland can be reduced, thus reducing the risk of cancer. In areas suffering from nuclear radiation, the World Health Organization has put forward the correct method of taking iodine tablets to prevent radiation: stable iodine tablets must be taken before or as soon as possible after exposure. Even a few hours after the accident, taking it can still prevent the thyroid gland from absorbing 50% iodine. Many people in China have taken iodine tablets to prevent nuclear radiation. Nuclear medicine experts say that iodine is a substance that thyroid needs in radiation. If radioactive iodine enters the human body, the use of iodine tablets may reduce the intake of radioactive iodine by the thyroid gland. But at present, the so-called nuclear pollution is mainly radioactive substances in the air or environment, so it is meaningless to eat iodine tablets, because these radioactive substances damage the thyroid gland, including the whole human organs. In daily life, the human body will also take in some iodine, because iodine is added to salt. Eating too much iodine tablets will not have serious side effects on the human body, but it will also have some adverse effects. Experts pointed out that there should be a more rational understanding of excessive radiation: first, there is radioactivity in nature. Of course, after this so-called natural disaster, the environmental radiation has obviously increased, which may have some influence on the human body. But this effect will only appear when the radiation dose increases obviously. Secondly, don't go to high radiation areas, pay attention to personal hygiene and avoid radioactive substances entering the human body.