Iodised salt
Iodised salt (also spelled iodized salt) is table salt mixed with a minute amount of various iodine-containing salts. The ingestion of iodide prevents iodine deficiency. Worldwide, iodine deficiency affects about two billion people and is the leading preventable cause of mental retardation.[1] It also causes thyroid gland problems, specifically endemic goitre. In many countries, iodine deficiency is a major public health problem that can be cheaply addressed by iodisation of salt.
Iodine is a micronutrient that is naturally present in the food supply in many regions. However, where natural levels of iodine in the soil are low and the iodine is not taken up by vegetables, iodine added to salt provides the small but essential amount needed by humans.
Chemistry, biochemistry and nutritional aspects
Four inorganic compounds are used as iodide sources, depending on the producer: potassium iodate, potassium iodide, sodium iodate, and sodium iodide. Any of these compounds supplies the body with its iodine required for the biosynthesis of the two thyroxin hormones. Animals also benefit from iodine supplements, and the hydrogen iodide derivative of ethylenediamine is the main supplement to livestock feed.[2]
Edible salt can be iodised by spraying it with a potassium iodate solution. Two ounces of potassium iodate, costing about USD$1.15, are required to iodise a ton of salt.[1] Salt is an effective vehicle for distributing iodine to the public because it does not spoil and is consumed by everyone in the population in fairly predictable amounts.[3]
In public health initiatives
Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of mental retardation.[1] According to public health experts, iodisation of salt may be the world's simplest and most cost-effective measure available to improve health, only costing USD$0.05 per person per year.[1] At the World Summit for Children in 1990, a goal was set to eliminate iodine deficiency by 2000. At that time, 25% of households consumed iodised salt, a proportion that increased to 66% by 2006.[1]
Salt producers are often, although not always, supportive of government initiatives to iodise edible salt supplies. Opposition to iodisation comes from small salt producers who are concerned about the added expense, private makers of iodine pills, concerns about promoting salt intake, and unfounded rumours that iodisation causes AIDS or other illnesses.[1] Iodisation programmes are more likely to be successful in areas where most edible salt is produced by a small number of large companies, as opposed to hundreds of smaller companies.
The United States Food and Drug Administration recommends[4] 150 micrograms of iodine per day for both men and women.
Kazakhstan
Kazakhstan, a country in Central Asia in which local food supplies seldom contain sufficient iodine, has drastically reduced iodine deficiency through salt iodisation programmes. Campaigns by the government and non-profit organisations to educate the public about the benefits of iodised salt began in the mid 1990s, with iodisation of edible salt becoming legally mandatory in 2002.[1]
United States
In the U.S. in the early 20th century, goiter was especially prevalent in the region around the Great Lakes and the Pacific Northwest.[5] David Murray Cowie, a professor of pediatrics at the University of Michigan, led the U.S. to adopt the Swiss practice of adding sodium iodide or potassium iodide to table and cooking salt. By the fall of 1924, Morton Salt Company began distributing iodised salt nationally.
See also
- History of salt
- Basil Hetzel
- Enriched flour serves an analogous function to "enriched salt."
- Water fluoridation, a similar but much more controversial public health intervention
- Iodine is a trace element, an essential dietary component in the same way as vitamins.
Notes
- ^ a b c d e f g McNeil, Donald G. Jr (2006-12-16). "In Raising the World's I.Q., the Secret's in the Salt". New York Times. Retrieved 2008-12-04.
- ^ Phyllis A. Lyday "Iodine and Iodine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a14_381
- ^ Willyard, Cassandra (June 2008). "Salt of the Earth: The public health community employs a mineral to fight infectious disease". Geotimes. American Geological Institute. Retrieved 2008-12-14.
- ^ 2005 CFR Title 21, Volume 2
- ^ Markel, When in Rains it Pours, p. 220
References
- Markel, Howard. (1987) When It Rains It Pours: Endemic Goiter, Iodized Salt, and David Murray Cowie MD. American Journal of Public Health, vol. 77 , pp. 219-229.
- 21 CFR 101.9 (c)(8)(iv)
- Newton County - Encyclopedia of Arkansas