Your body needs iodine in trace amounts. Your thyroid gland uses it to make thyroid hormones, whose function is to regulate important metabolic processes. Underproduction can lead to various thyroid diseases, as well as growth problems in children. Because your body cannot make iodine, you must get it from food.
History
Iodine was discovered in 1811 by French chemist Barnard Courtois, who accidentally extracted it from seaweed by adding sulfuric acid. However, although seaweed has been used to treat thyroid swelling or endemic goiter since ancient times, it was not until 1915 that E.C. Kendall isolated iodine from the thyroid proteins. Dr. David Marine and O.P. Kimball of Cleveland, Ohio then proved that endemic goiter was caused by iodine deficiency.
Thyroid Hormones
The thyroid hormones T3 and T4 help set your metabolic rate, which affects mental and physical growth in children. The thyroid gland stores both hormones and releases them into the blood as necessary. They bind to special receptors in target areas in your body, such as your brain and liver. Aside from causing endemic goiter, a lack of iodine can lead to hypothyroidism in adults and birth defects and developmental retardation in children. Iodine deficiency is considered the most common cause of preventable brain damage worldwide.
Dosages
Iodine is mostly found in the ocean and in the soil of land near the ocean. Foods that are naturally high in iodine include seaweed, seafood and ocean fish, which can concentrate iodine from the water. Eating iodized salt is also a convenient way of meeting your iodine requirements. Daily requirements for iodine vary throughout life. Infants need about 110 mcg a day, children need 90 mcg, adults require 150 mcg, pregnant women need 220 mcg and lactating women, 290 mcg.
Additional Information
Other foods that contain iodine include dairy foods, eggs and beans. However, it's important to note that the iodine content in foods can vary quite a bit. You can also take supplements in the form of potassium iodide, but generally this is not necessary, because you usually consume sufficient amounts of iodine from your diet. Only when nuclear disasters contaminate the environment might you require a safe iodine supplement.
References
- Jefferson Lab: The Element Iodine
- "Journal of the American Medical Association"; Landmark Article, June 19, 1915. The Isolation in Crystalline Form of the Compound Containing Iodin, Which Occurs in the Thyroid. Its Chemical Nature and Physiologic Activity; E.C. Kendall; October 1983
- International Council for the Control of Iodine Deficiency Disorders: History of Salt Iodization
- Linus Pauling Institute; Iodine; Jane Higdon; April 2003
