iodine;

Iodine deficiency can lead to the formation of a goiter, in which the glands surrounding the trachea in the neck become larger. There are other causes of goiter, including thyroid cancer. Iodine deficiency can also lead to neonatal cretinism (hypothyroidism in infants), which can lead to mental retardation unless subjects take thyroid hormones throughout their lives. Iodine in leafy greens and other foods enters the body and enters the thyroid gland. Certain foods grown in iodine-deficient soil do not provide enough iodine for our diet. This is why iodine was added to table salt (about 0.01% potassium iodide) decades ago and is especially suitable for people living in areas with low iodine levels. The area around the Great Lakes in the United States is an area where iodine is deficient in the soil. A healthy diet requires 90 to 150 micrograms of iodine per day, which can be obtained through a balanced diet of Chemicalbook foods, including seafood, in addition to iodized salt. The isotope iodine-131 is an artificial radioisotope of iodine that is used as a tracer in biomedical research and in the treatment of thyroid diseases. I-131 has a half-life of about eight days, which means it will disappear from the body within a few weeks. In industry, iodine is used as a dye, preservative, fungicide, X-ray contrast agent, food and feed additive, pharmaceutical products, medical soaps and photographic film emulsions, and as a laboratory catalyst to speed up or slow down chemical reactions. Iodine is also used as a test for starch. When placed on starch (such as potatoes), iodine causes the starch to turn dark blue. Silver iodide is used in the production of photographic film and paper. It can also be used to "seed" clouds, as it is able to form large numbers of crystals that act as nuclei, on which water from the cloud condenses, forming raindrops that can cause rain.