Iodised salt
Worldwide, iodine deficiency affects about two billion people and is the leading preventable cause of intellectual and developmental disabilities.
Iodine is a micronutrient and dietary mineral that is naturally present in the food supply in some regions, especially near sea coasts but is generally quite rare in the Earth's crust since iodine is a so-called heavy element, and abundance of chemical elements typically declines with greater atomic mass.
[3] Poor manufacturing techniques and storage processes can also lead to insufficient amounts of iodine in table salt.
Any of these compounds supplies the body with the iodine required for the biosynthesis of thyroxine (T4) and triiodothyronine (T3) hormones by the thyroid gland.
[5] Salt is an effective vehicle for distributing iodine to the public because it does not spoil and is consumed in more predictable amounts than most other commodities.
[8] Salt that is iodized with iodide may slowly lose its iodine content by exposure to excess air over long periods.
[11] Contrary to popular belief, iodised salt cannot be used as a substitute for potassium iodide (KI) to protect a person's thyroid gland in the event of a nuclear emergency.
[1] Optional additives include: Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual and developmental disabilities.
[1] The United States Food and Drug Administration recommends[14] 150 micrograms (0.15 mg) of iodine per day for adults.
[18] Iodine Deficiency Disorders were detected as a major public health issue by Brazilian authorities in the 1950s when about 20% of the population had a goitre.
[19] The National Agency for Sanitary Vigilance (ANVISA) is responsible for setting the mandatory iodine content of table salt.
To avoid excess consumption of iodine, the iodizing of Brazilian table salt was reduced to 15–45 mg/kg in July 2013.
In 1996, the Chinese Ministry of Public Health estimated that iodine deficiency was responsible for 10 million cases of intellectual developmental disorders in China.
A national survey of 1990 revealed the prevalence of iodine deficiency to be 20-80% in different parts of Iran indicating a major public health problem.
[29] According to the 568/2002 law signed by the Romanian parliament and republished in 2009, since 2002 iodized salt has been distributed mandatory in the whole country.
Learning of Hunziker's theory, Bayard conducted experiments with iodised salt containing only tiny amounts of iodine in villages badly affected by goitre.
[34] Today, iodised salt continues to be used in Switzerland, where historically endemic iodine deficiency has been eradicated.
Dr. Ouaess linked these results with the fact that natural drinking water sources in Syria do not contain enough minerals.
[35] UK milk had historically provided an alternative avenue for iodine intake, for which it is indirectly fortified through cattle feed.
A 2017 study found that introducing iodized salt in 1924 raised the IQ of one-quarter of the population most deficient in iodine.
[40] These findings "can explain roughly one decade's worth of the upward trend in IQ in the United States (the Flynn effect)".
[40] The study also found "a large increase in thyroid-related deaths following the countrywide adoption of iodized salt, which affected mostly older individuals in localities with a high prevalence of iodine deficiency" between 1910–1960, a high short-term price for iodization's long-running benefits.
Contrary to popular belief, however, iodized salt affects neither colour, taste, nor consistency of pickles.
