Iodide deficiency disorder

The thyroid gland is the only part of the body that absorbs iodine. Thyroid cells use iodine to produce thyroid hormones, which regulate metabolism. Low levels of iodine in the diet can lead to thyroid-hormone deficiencies and goiters, which are enlarged thyroid glands. In serious cases, low levels of thyroid hormones can cause birth defects and brain damage. In the United States, potassium iodide is added to most table salt to protect against dietary iodine deficiency. Even small amounts of added iodine can prevent iodine-deficiency disorders. However, there are parts of the world in which iodine deficiency is still prevalent. 

The observation of toxicity of iodine mainly focused on the iodide or iodate, which is normally present in iodized salt, milk, water and leachate of foodstuffs. However, the toxicity of some other species of iodine may be much higher than that of iodide and iodate. For the prevention of iodine deficiency disorders, iodized oil was used as an injection or administered orally in many countries iodized oil is normally produced by binding iodine atoms to the polyunsaturated fatty acid in the oil (Zimmermann et al, 2000). After administration, it was supposed that iodine is released gradually as iodide to maintain a constant supply of iodine to the body. Experience in the past decades shows that the utilization of iodized oil is safe. However, acute poisoning of iodized oil to children who are orally administered was reported in China in 1998 this may be related to the species of iodine, which may be more toxic than iodide or iodate. Iodine has been used as an effective, simple, and cost-efficient means of water disinfection (Backer and Hollowell, 2000), in which the active disinfectant species are elemental iodine and hypo-iodous acid. Doses of iodine below 1 mg/1 kill bacteria within minutes. Elemental iodine and hypoiodous acid remain in the disinfected water, which may be toxic to humans. 

Carbonic anhydrase (CA) exists in three known soluble forms in humans. All three isozymes (CA I, CA II, and CA III) are monomeric, zinc metalloenzymes with a molecular weight of approximately 29,000. The enzymes catalyze the reaction for the reversible hydration of C02. The CA I deficiency is known to cause renal tubular acidosis and nerve deafness. Deficiency of CA II produces osteopetrosis, renal tubular acidosis, and cerebral calcification. More than 40 CA II-defi-cient patients with a wide variety of ethnic origins have been reported. Both syndromes are autosomal recessive disorders. Enzymatic confirmation can be made by quantitating the CA I and CA II levels in red blood cells. Normally, CA I and CAII each contribute about 50% of the total activity, and the CAI activity is completely abolished by the addition of sodium iodide in the assay system (S22). The cDNA and genomic DNA for human CA I and II have been isolated and sequenced (B34, M33, V9). Structural gene mutations, such as missense mutation, nonsense... 

For example, inclusion of 0.02 % KI, potassium iodide, in ordinary table salt has nearly eUminated goiter in the United States. Goiter is a disorder of the thyroid gland caused by a deficiency of iodine. Alineral water tastes better than purer, distilled water. 

---