Iodine deficiency
<p ><a href="http://en.wikipedia.org/wiki/Iodine" title="Iodine" >Iodine</a> is an essential <a href="http://en.wikipedia.org/wiki/Trace_element" title="Trace element" >trace element</a>; the <a href="http://en.wikipedia.org/wiki/Thyroid_hormone" title="Thyroid hormone" >thyroid hormones</a><a href="http://en.wikipedia.org/wiki/Thyroxine" title="Thyroxine" class="mw-redirect" >thyroxine</a> and <a href="http://en.wikipedia.org/wiki/Triiodotyronine" title="Triiodotyronine" class="mw-redirect" >triiodotyronine</a> contain iodine. In areas where there is little iodine in the diet—typically remote inland areas where no marine foods are eaten—<b>iodine deficiency</b> gives rise to <a href="http://en.wikipedia.org/wiki/Goiter" title="Goiter" class="mw-redirect" >goiter</a>(so-called <a href="http://en.wikipedia.org/wiki/Endemic_goiter" title="Endemic goiter" class="mw-redirect" >endemic goiter</a>), as well as <a href="http://en.wikipedia.org/wiki/Cretinism" title="Cretinism" >cretinism</a>, which results in developmental delays and other health problems. While noting recent progress, <i><a href="http://en.wikipedia.org/wiki/The_Lancet" title="The Lancet" >The Lancet</a></i> noted, "According to <a href="http://en.wikipedia.org/wiki/World_Health_Organization" title="World Health Organization" >WHO</a>, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age. ... Thus iodine deficiency, as the single greatest preventable cause of <a href="http://en.wikipedia.org/wiki/Mental_retardation" title="Mental retardation" >mental retardation</a>, is an important <a href="http://en.wikipedia.org/wiki/Public_health" title="Public health" >public-health</a> problem."<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Iodine_deficiency#cite_note-0" >[1]</a></sup>
In some such areas, this is now combatted by the addition of small amounts of iodine to table salt in form of<a href="http://en.wikipedia.org/wiki/Sodium_iodide" title="Sodium iodide" >sodium iodide</a>, <a href="http://en.wikipedia.org/wiki/Potassium_iodide" title="Potassium iodide" >potassium iodide</a>, and/or <a href="http://en.wikipedia.org/wiki/Potassium_iodate" title="Potassium iodate" >potassium iodate</a>—this product is known as <i><a href="http://en.wikipedia.org/wiki/Iodized_salt" title="Iodized salt" class="mw-redirect" >iodized salt</a></i>. Iodine compounds have also been added to other foodstuffs, such as flour, water and milk in areas of deficiency.<sup id="cite_ref-1" class="reference" ><a href="http://en.wikipedia.org/wiki/Iodine_deficiency#cite_note-1" >[2]</a></sup><a href="http://en.wikipedia.org/wiki/Seafood" title="Seafood" >Seafood</a> is also a well known source of iodine.<sup id="cite_ref-2" class="reference" ><a href="http://en.wikipedia.org/wiki/Iodine_deficiency#cite_note-2" >[3]</a></sup> Thus, iodine deficiency is more common in mountainous regions of the world where food is grown in soil poor in iodine.</p>