Why can salt protect against radiation?

Can iodized salt prevent radiation? Why can it prevent radiation? Can eating iodized salt prevent radiation? What about soy sauce and bean paste?

Iodine is the main raw material for the synthesis of thyroxine in the body, and thyroxine protects thyroid from iodine 13 1 in radioactive dust. Iodine 13 1 can be quickly absorbed by human body, leading to cancer and hereditary diseases.

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 cause cancer. 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.

(The following text is from Wikipedia)

The discovery of iodine

Iodine was discovered when Barnard courtois was making potassium nitrate. Iodine molecules are relatively stable in acidic environment.

Use? Iodine deficiency can lead to iodine deficiency and affect thyroid, so people who can't get enough iodine in their daily diet should eat iodized salt (sodium iodide, potassium iodide or potassium iodate).

Iodine tincture (also known as alcohol solution of iodine, iodine and potassium iodide) is an emergency disinfectant.

Photographic film contains potassium iodide.

The filament in an electric lamp contains tungsten iodide.

Nitrogen iodide is an explosive.

Iodine turns blue when it meets starch, which can verify the existence of starch.

[Editor] There are thirty isotopes of iodine, of which only iodine-127 is stable. Radioactive iodine-13 1 can be used to treat cancer, such as breast cancer.

Influence on human body [Editor] Human nutrition problem Iodine is an essential element for human body, which is used to produce thyroxine hormone to regulate cell metabolism and the development and growth of neuromuscular tissues (especially the brain of newborns) [1]. Iodine deficiency [2] is the most common cause of avoidable brain injury diseases, and it is estimated that 50 million people in the world suffer from it. According to the survey of IDD by the British Geological Survey, it is estimated that there are 2 billion people in the world with insufficient iodine intake, including 285 million school-age children [3]; Among them, cretinism is about 5.7 million, brain injury is 26 million and goiter is 655 million [4]; These populations are mainly concentrated in Central Africa, Southeast Asia, Central Asia, Central and Eastern Europe [5].

Severe iodine deficiency during pregnancy will damage fetal development, especially brain development, which can lead to a significant decline in IQ, because myelination in the nervous tissue of fetus and newborn is the most active and controlled by thyroxine. Severe iodine deficiency can lead to cretinism, abortion and stillbirth. Other common effects of chronic iodine deficiency include neuromuscular dysfunction and cognitive impairment. The initial clinical symptom is goiter. Due to iodine deficiency, the efficiency of thyroid absorption of iodine in blood increases. It is a compensatory reaction to iodine deficiency, and eventually a visible lump will form in the neck, called goiter, which can be diagnosed by palpation or ultrasonic scanning. This is also one of the evaluation indexes of iodine nutrition recommended by the International IDD Prevention and Control Team of the World Health Organization (WHO).

When iodine is deficient, TSH will increase, which is due to the fact that thyroxine cannot be synthesized and the negative feedback mechanism is continuously used to stimulate the secretion of thyroid stimulating hormone (TSH).

Excessive iodine can cause the following symptoms: thyroiditis, goiter, hypothyroidism or hyperthyroidism, papillary thyroid carcinoma and allergic reaction. Excessive iodine intake will damage thyroid function. The initial reaction is that thyroid stimulating hormone (TSH) in the blood is higher than normal. When the intake was as high as 750 μg/d, TSH concentration increased obviously. Because the increase of TSH concentration reflects the danger of thyroid insufficiency, under the condition of adequate iodine intake, the increase of plasma TSH concentration is regarded as the index of iodine excess harm, and the increase of TSH caused by iodine deficiency is not considered.

The content and distribution of iodine in human body is about 25 ~ 36 mg. Iodine is mostly concentrated in the thyroid gland to synthesize thyroxine, which is about 15~20 mg under normal conditions, and may be less than 20 μg when iodine is deficient. Thyroxine in human body consists of triiodothyronine (T3), T4 and tetraiodothyronine (T4), of which iodine accounts for 59% and 65% respectively. Except thyroid, a small amount of iodine is distributed in muscles, skin, blood and central nervous system.

The absorption, storage and excretion of iodine absorbed into the body are combined with amino acids; Or in a free state such as iodate (IO3? ) and iodine ion (me? ) form exists. Iodate can be reduced to iodine ion by glutathione in human body. The form of iodine ion has good absorption efficiency in human body, and most of it can be absorbed by digestive tract. Organic forms such as iodine-bound amino acids can also be absorbed, but the efficiency is poor. The absorbed iodine is iodine ion (I? ) exists in the blood and is sent to the thyroid gland for storage to synthesize thyroxine. Thyroxine T4 and T3 in food can be directly absorbed, so T4 can be directly taken orally as a drug to treat thyroxine deficiency in medicine.

Because the kidney has no mechanism to retain iodine ions, most of the excess iodine is discharged from urine, and a few are discharged from feces and sweat.

Physiological and biochemical functions The main function of iodine is to synthesize thyroxine. Thyroxine is an important hormone, its main function is to promote metabolism, stimulate tissue growth, maturity and differentiation, accelerate heartbeat and increase cardiac output. Many other hormones need to be combined with thyroxine to play an effective role. For example, in the early development process, growth hormone and thyroxine can work together to make children grow and develop normally. Thyroxine (T4) and triiodothyronine (T3) have two forms. The concentration of T4 in blood is high, but the activity of T3 is high. The other reverse T3(rT3) is an inactive metabolite. Different deiodinase (5'- deiodinase, 5- deiodinase) can convert T4 into T3 and rT3, thus regulating the activity of thyroxine in vivo.

The thyroid gland consists of many vesicles, which are filled with glial proteins and surrounded by a layer of thyroid cells. Thyroid cells pump iodine ions through sodium and potassium, consume ATP, send them to cells and oxidize them into iodine (I). Then iodine combines with tyrosine residues on thyroglobulin to form monoiodotyrosine (MIT), and then iodine is added to form diiodotyrosine (DIT). In the vesicle, two DITs are coupled to form T4; DIT and MIT are coupled to form T3. At this time, T4 and T3 are still bound to thyroglobulin. When it is released, the whole complex will be sent to thyroid cells, where thyroglobulin will be hydrolyzed and T4 and T3 can be released into the blood. In blood, T4 and T3 are mostly combined with transporters, which are sent to target tissues and enter the nucleus of target cells to promote or inhibit gene expression, thus controlling cell growth and metabolism.

Food sources Most of the iodine needed by the human body comes from diet, such as seaweed, kelp, lobster, shellfish, green vegetables, eggs, milk and cereals. [6], in which kelp, seaweed and other foods contain the most iodine. To prevent iodine deficiency, we can take measures to strengthen food iodization, and add appropriate amount of potassium iodide and potassium iodate to salt to supplement iodine intake. The World Health Organization recommends that 20 to 40 milligrams of iodine can be added to each kilogram of salt. The Codex Alimentarius Commission's salt standard refers to iodized salt, and it is suggested that the health authorities in various countries should evaluate the local iodine deficiency to determine the highest and lowest iodine content in salt. The WHO/FAO Joint Expert Committee on Food Additives (JECFA) assessed the safety of iodine, and suggested that the provisional maximum allowable daily intake of iodine should be 17 μ g/kg body weight.

Can iodine really protect against radiation? Why can it prevent radiation?