Abnormal Development - Iodine Deficiency
Introduction
Iodine deficiency disorders (IDD) is the single most common cause of preventable mental retardation and brain damage in the world. Iodine (Greek, ioeides = violet) is required for the synthesis of thyroid hormone, a key regulator of neurological development. IDD causes goiters and decreases the production of hormones vital to growth and development.
- 1.6 billion people are at risk
- IDD affects 50 million children
- 100,000 cretins are born every year
Children with IDD can grow up stunted, apathetic, mentally retarded and incapable of normal movement, speech or hearing. IDD in pregnant women cause miscarriage, stillbirth and mentally retarded children. A teaspoon of iodine is all a person requires in a lifetime, but because iodine cannot be stored for long periods by the body, tiny amounts are needed regularly. In areas of endemic iodine deficiency, where soil and therefore crops and grazing animals do not provide sufficient dietary iodine to the populace, food fortification and supplementation have proven highly successful and sustainable interventions. Iodized salt programs and iodized oil supplements are the most common tools in the fight against IDD.
- Links: Endocrine - Thyroid Development |
Some Recent Findings
- Food Standards Australia New Zealand (FSANZ) - 22nd Australian Total Diet Study A total diet study of five trace elements: iodine, selenium, chromium, molybdenum, and nickel.
- Modest Thyroid Hormone Insufficiency during Development Induces a Cellular Malformation in the Corpus Callosum: A Model of Cortical Dysplasia[1]"Whilst the majority of Australians had dietary intakes approaching or above the estimated average requirement (EAR) or AI for selenium, molybdenum and chromium, a substantial proportion of the population had iodine intakes below the EAR. FSANZ has subsequently commissioned further analyses of iodine levels in Australian foods and will be introducing mandatory fortification of iodine in bread, from September 2009."
Iodine and Thyroid Hormone
Iodine incorporated into thyroid horomone, Thyroxine (T4)
Salt
Where salt iodization has been in place for over five years, improvement in iodine status has been overwhelming.Over the last decade, the number of countries with salt iodization programmes doubled, rising from 46 to 93. As a result, today 68% of the 5 billion people living in countries with IDD have access to iodized salt and the global rates of goitre, mental retardation and cretinism are falling fast.
(some text information from WHO page)
Iodine Requirements
The current WHO recommended daily iodine intakes are:
- 50 micrograms for infants (first 12 months of age)
- 90 micrograms for children (2-6 years of age)
- 120 micrograms for school children (7-12 years of age)
- 150 micrograms for adults (beyond 12 years of age)
- 200 micrograms for pregnant and lactating women
- Links: World Health Organization - Micronutrient deficiencies Eliminating iodine deficiency disorders | World Health Organization - Iodine data by country)
I - Iodine
This information is about Iodine the element, dietry intake is in the form of iodine as a salt. The solid halogen was discovered in 1811 by Bernard Courtois (1777-1838) in seaweed. Iodine (Greek, ioeides = violet) was named for the color of its vapour.
- Atomic number 53
- Density g/mL 4.92
- Atomic weight u 126.9045
- Melting point K 386.7
- Bonding radius A 1.33
- Boiling point K 458.4
- Atomic radius A 1.32
- Heat of vaporization kJ/mol 20.752
- Ionization Potential V 10.451
- Heat of fusion kJ/mol 7.824
- Electronegativity - 2.66
- Specific heat J/gK 0.214
- The oxide is a strong acid.
- Crystal are orthorhombic.
- Iodine has been used for its antibacterial qualities.
Australian Data
(from IDD Prevalence and Control Program Data)
(For other countries see also IDD Regional Data Page)
IDD Prevalence and Control Program Data
Last Modified: 6/98
Australia
I. IDD Prevalence
Goitre:
No national IDD data. Goiter historically limited to mountains of east and Tasmania. Before prophylaxis was introduced in 1950, IDD was greater than 50%. Presently, IDD not likely.
Cretinism:
Not present
TSH:
Neonatal TSH in screening shows levels compatible with iodine sufficiency, including Tasmania.
Urinary Iodine:
Current values: Tasmania 229-356 mcg/L, Sydney 180 mcg/L.
II. Salt Legislation
- Legislation:
- Legislation for Animals: No legislation, but widely used.
- Level Salt Iodization Required (ppm): 50
- Compound: KI
- Year Enacted: NA
- Latest Revision: NA
III. IDD Coordination
IDD Responsible Parties:
No national surveillance program
IV. Salt Supply
- Is Iodized Salt Available: Yes
- Percent Iodized Salt Available: No Data Available
- Percent of Salt Which is Imported:Australia is salt exporter
- Salt Imported from: NA
- Salt Production:
Iodized table salt has been available for over 50 years. However, noniodized salt is preferred and data indicate that less than a third of the consumed salt is iodized.
- Iodine (ppm): 50
- Compound: KI
- Method of Iodization: No Data Available
- Package Method: No Data Available
- Estimated daily per capita salt consumption: No Data Available
- Estimated % of all salt consumed by people which is adequately iodized (household level): No Data Available
- Cost of Iodized Salt (kg): No Data Available
- Cost of Uniodized Salt (kg): No Data Available
- Year: No Data Available
- Price differential between city and rural areas: No Data Available
- Estimated difference (urban/rural, %): No Data Available
- Time between production and consumption of iodized salt in remote areas (weeks): No Data Available
V. Supplementation:
- Total Number Supplemented:None
- % administered orally: NA
- % administered by injection: None
- Target Population: None.
- Other Supplementation Activities:
Iodized bread was introduced in 1963 in Canberra and in 1966 in Tasmania. It continues to be a source of iodine.
VI. Monitoring Activities
The following indicators are available to monitor IDD:
- Goitre:
- Urinary Iodine:
- Salt:
VII. Comments
Dietary diversification and use of iodine in farm animals has contributed to iodine sufficiency, and iodine deficiency does not appear a current problem. However, no national surveillance system exists. Recent informal reports raise questions of return of iodine deficiency to Tasmania and assessment is underway (1998).
VIII. Sources
IDD NL 9(1):11, 1993
- Links: Australia New Zealand Food Standards Code STANDARD 2.10.2 SALT AND SALT PRODUCTS
References
- ↑ <pubmed>17317780</pubmed>
Reviews
Articles
Search Pubmed
June 2010 "Iodine Deficiency"
Search Pubmed: Iodine Deficiency
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Cite this page: Hill, M.A. (2024, April 25) Embryology Abnormal Development - Iodine Deficiency. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Abnormal_Development_-_Iodine_Deficiency
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G