Iodine is found in the human body in the thyroid gland; other organs that are high in iodine are the salivary glands, stomach, pituitaries and the ovaries. In the thyroid iodine is converted into tiroxine and triiodotironine, which has a reglation function in some metabolical functions, especially the thermal ones.
People from the developed societies have a problem with the iodine intake, compared to the ones that live in the ordinary and traditional settlements, because of the differences of the alimentation. Milk is a major source of iodine, and its level is considered to be double, because the cattles are fed with iodine suppliments and because the utters are sterilised with iodine-based antiseptics before milking.
The highest products in iodine are code, oysters, shrimps, hering, sunflower, algae and mushrooms. Eating certain food, like sweet potatoes, can lower the rate of iodine asimilation, this metabolic process affectind the ones that live in places where iodine is deficitary.
Iodine is necessary especially in the first 3 months of pregnancy, so that the nervous system of the baby could develop; mothers with iodine deficiency risk to have children with cretinism.
The first person to use iodine in medicine was the French chemist Jean-Francois Coindet, dissolving the iodine into alcohol along potassium iodide, this mixture being used as a drug against endemic goitre. He observed that the first traditional treatments consisted in consuming algae, which were rich in iodine, and so he believed that iodine was the active ingredient. He was right, but when his patients received the drug, they suffered severe gastric pains that occured because of the irritant effects, and the treatment was abandoned.
Although the iodine solution has failed as a goitre drug, it became an accepted treatment for opened wounds, even though its antiseptic properties were unknown. Iodine and its compounds were used a while as antiseptics and disinfectants; as time passed by, they were replaced with some solutions that were less aggresive.
In 1830 another link between goitre and the iodine level was established, research showing that in the places where the goitre was endemic, there were water reservoirs with low-iodine level, but the process of curing goitre in the middle of the XIXth century with this element were stopped, because of the visible damage of the patients made by the excess of iodine.
In 1850 it was established that iodine is an oligoelement, essential for living organisms. The iodine deficiency is making these symptoms present: hypotiroidy, thyroidian nanism, low brain activity, endemical goitre, anemy, mixedem, obesity, thick and dry skin, chills. The excess of iodine conducts to hyperphagy (although the patients with high levels of thyroidian hormones are losing weight), iritability, permanent sensations of warm, exoftalmia and infertility.