Introduction: Recently, as the nuclear radiation happened in Japan, many people heard that can prevent radiation, so they rushed to buy iodized salt. However, does iodine can really help prevent radiation? Actually, it is not the fact.

The physiological effects of iodine are realized by the hormone in human body. Thyroid hormone is one of the most important hormones in the human body. Then what are the physiological effects of iodine? The following passage will give a detailed introduction.

First of all, iodine can maintain the metabolism of energy in the body.
Iodine can break down the substances in human body, so as to provide the energy required for the basic life activities. What's more, it can promote the production of heat, so that to maintain the normal temperature of human body. Iodine deficiency will decrease the synthesis of thyroid hormone, which may cause damage on the basic life activities and decline physical ability.

Secondly, iodine can promote physical development.
Iodine can regulate the development of bones and muscles for children at the growth and developmental stage. Iodine deficiency can lead to physical retardation, muscle weakness and other symptoms.

Thirdly, iodine can promote the development of brain.
For the fetuses and infants, the development of their brain is closely related with iodine. As a result, iodine deficiency will greatly affect brain development, and even may lead to mental retardation, while this disorder is essentially irreversible.

After the above introduction, you may have a clear understanding of the physiological effects of iodine. Then a lot of people may also ask: what foods contain a large number of iodine?

In general, foods which contain great amounts of iodine are mostly seafood, such as kelp, seaweed, dried scallop, mussel, sea cucumber, jellyfish, lobster, and so on. Seaweed contains the highest content of iodine (one kilogram of fresh kelp contains more than 2000 micrograms of iodine); and followed by marine fish and shellfish. Apart from seafood, other foods such as egg, milk and meat also contain a large number of iodine. Plant food contains the lowest amount of iodine in all the foods.

In addition, iodized salt contains a really small amount of iodine, especially the purified salt. Every one kilogram of sea salt contains about 20 micrograms of iodine. If one person takes in 10 grams of salt every day, he can only take in 2 micrograms of iodine. This can hardly meet the need for the prevention of the disorders caused by iodine deficiency.