Iodine deficiency
[4] In particular, around 1980 the practice of using potassium iodate as dough conditioner in bread and baked goods was gradually replaced by the use of other conditioning agents[5] such as bromide.
[citation needed] Iodine deficiency resulting in goiter occurs in 187 million people globally as of 2010[update] (2.7% of the population).
[9] As a result of restricted diet, isolation, intermarriage, etc., as well as low iodine content in their food, children often had peculiar stunted bodies and retarded mental faculties, a condition later known to be associated with thyroid hormone deficiency.
While reporting recent progress towards overcoming iodine-deficiency disorders worldwide, The Lancet noted: "According to World Health Organization, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age."
There is a total of 15–20 mg of iodine in the human body, primarily concentrated in thyroid tissue and hormones.
The diagnostic workup of a suspected iodine deficiency includes signs and symptoms and possible risk factors mentioned above.
Mild cases may be treated by using iodized salt in daily food consumption, drinking more milk, eating egg yolks, and saltwater fish.
[23][24] The recommended daily intake of iodine for non-pregnant adults is 150 μg to maintain normal thyroid function.
[20] Being pregnant while iodine-deficient additionally carries the risk of causing congenital iodine deficiency syndrome in the newborn.
[25] Iodine deficiency resulting in goiter occurs in 187 million people globally as of 2010[update] (2.7% of the population).
Among other nations affected by iodine deficiency, China and Kazakhstan have begun taking action, while Russia has not.
"[27] Iodine deficiency has largely been confined to the developing world for several generations, but reductions in salt consumption and changes in dairy processing practices eliminating the use of iodine-based disinfectants have led to increasing prevalence of the condition in Australia and New Zealand in recent years.
Lacking iodine during human development causes a fall, in average, of 12 intelligence quotient (IQ) points in China.
[30] A study of U.S. military data collected during the First and Second World Wars found that the introduction of salt iodization in the U.S. in the 1920s resulted in an increase in IQ, by approximately one standard deviation, for the quarter of the U.S. population most deficient in iodine, explaining about "one decade's worth of the upward trend in IQ" in the U.S. (i.e., the Flynn effect).
[31] The same study documented "a large increase in thyroid-related deaths following the countrywide adoption of iodized salt, which affected mostly older individuals in localities with high prevalence of iodine deficiency" between 1910–1960.
[35] A 2014 meta-analysis found that iodine supplementation "improves some maternal thyroid indices and may benefit aspects of cognitive function in school-age children, even in marginally iodine-deficient areas".
[36] In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency gives rise to hypothyroidism, symptoms of which are extreme fatigue, goiter, mental slowing, depression, weight gain, and low basal body temperatures.
[37] Iodine deficiency is the leading cause of preventable intellectual disability, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element.
In the coastal communities, saltwater fish were an important part of the diet, and because of the presence of iodine in seawater, goiter was less common than in the inland districts.
