Iodine deficiency
Encyclopedia
Iodine
is an essential trace element
; the thyroid hormone
s thyroxine
and triiodotyronine contain iodine. In areas where there is little iodine in the diet—typically remote inland
areas where no marine foods are eaten—iodine deficiency gives rise to
goiter (so-called endemic goiter), as well as cretinism
, which results in developmental delays and other health problems.
While noting recent progress, The Lancet
noted, "According to WHO
, 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 mental retardation
, is an important public-health
problem."
In some such areas, this is now combatted by the addition of small amounts of iodine to table salt in form of sodium iodide
, potassium iodide
, and/or potassium iodate
—this product is known as iodized salt. Iodine compounds have also been added to other foodstuffs, such as flour, water and milk in areas of deficiency. Seafood
is also a well known source of iodine. Thus, iodine deficiency is more common in mountainous regions of the world where food is grown in soil poor in iodine.
(one of the two thyroid hormones) in the blood, due to lack of dietary iodine to make it, gives rise to high levels of thyroid stimulating hormone TSH
, which stimulates the thyroid gland to increase many biochemical processes; the cellular growth and proliferation can result in the characteristic swelling or hyperplasia of the thyroid gland, or goiter. In mild iodine deficiency, levels of triiodiothyronine (T3) may be elevated in the presence of low levels of levothyroxine, as the body converts more of the levothyroxine to triiodothyronine as a compensation. Some such patients may have a goiter, without an elevated TSH. The introduction of iodized salt since the early 1900s has eliminated this condition in many affluent countries; however, in Australia
, New Zealand
, and several Europe
an countries, iodine deficiency is a significant public health problem. It is more common in third-world nations. Public health initiatives to lower the risk of cardiovascular disease have resulted in lower discretionary salt use at the table, and with a trend towards consuming more processed foods. The noniodized salt used in these foods also means that people are less likely to obtain iodine from adding salt during cooking.
Goiter is said to be endemic when the prevalence in a population is > 5%, and in most cases goiter can be treated with iodine supplementation. If goiter is untreated for around five years, however, iodine supplementation or thyroxine treatment may not reduce the size of the thyroid gland because the thyroid is permanently damaged.
of 10 to 15 IQ points. It has been speculated that deficiency of iodine and other micronutrients may be a possible factor in observed differences in IQ between ethnic groups: see race and intelligence
for a further discussion of this controversial issue.
Cretinism is a condition associated with iodine deficiency and goiter, commonly characterised by mental deficiency, deaf-mutism, squint, disorders of stance and gait, stunted growth and hypothyroidism
. Paracelsus
was the first to point out the relation between goitrous parents and mentally retarded children.
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 deficiency. Diderot
, in his 1754 Encyclopédie
, described these patients as "crétins". In French, the term "crétin des Alpes" also became current, since the condition was observed in remote valleys of the Alps
in particular. The word cretin appeared in English in 1779.
Iodine deficiency is the leading cause of preventable mental retardation
, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations, but as of March 2006, iodine deficiency remained a serious public health problem in the developing world. Iodine deficiency is also a problem in certain areas of Europe. In Germany it has been estimated to cause a billion dollars in health care costs per year.
Iodine may also help prevent diseases of the oral and salivary glands.
(NIS). Its role in mammary tissue is related to fetal and neonatal development, but its role in the other tissues is unknown. It has been shown to act as an antioxidant in these tissues.The US Food and Nutrition Board and Institute of Medicine recommended daily allowance of iodine ranges from 150 micrograms /day for adult humans to 290 micrograms /day for lactating mothers. However, the thyroid gland needs no more than 70 micrograms /day to synthesize the requisite daily amounts of T4 and T3. These higher recommended daily allowance levels of iodine seem necessary for optimal function of a number of body systems, including lactating breast, gastric mucosa, salivary glands, oral mucosa, thymus, epidermis, choroid plexus, etc.
Moreover, iodine can add to double bonds of docosahexaenoic acid
and arachidonic acid
of cellular membranes, making them less reactive to free oxygen radicals.
, South-East Asia and Africa
.
India
is the most outstanding, with 100 million suffering from deficiency, 4 million from goiter, and 0.5 million from cretinism
.
Among other nations affected by iodine deficiency, China and Kazakhstan
have begun taking action, while Russia
has not. Successful campaigns for the adoption of the use of iodized salt require education of salt producers and sellers and a communication campaign directed at the public. The cost of adding iodine to salt is negligible—"Only a few cents a ton."
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. A proposal to mandate the use of iodized salt in most commercial breadmaking is expected to be adopted in 2009. In a study of the United Kingdom published in 2011, almost 70% of test subjects were found to be iodine deficient. The study's authors suggested an investigation regarding "evidence-based recommendations for iodine supplementation".
In addition, a 24-hour urine iodine collection is a useful medical test
, as approximately 90% of ingested iodine is excreted in the urine. If a 24-hour urine collection is not practical, a random urine iodine-to-creatinine ratio can alternatively be used.
In an adult, 150 µg
/d is sufficient for normal thyroid function.
.
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
is an essential trace element
Trace element
In analytical chemistry, a trace element is an element in a sample that has an average concentration of less than 100 parts per million measured in atomic count, or less than 100 micrograms per gram....
; the thyroid hormone
Thyroid hormone
The thyroid hormones, thyroxine and triiodothyronine , are tyrosine-based hormones produced by the thyroid gland primarily responsible for regulation of metabolism. An important component in the synthesis of thyroid hormones is iodine. The major form of thyroid hormone in the blood is thyroxine ,...
s thyroxine
Thyroxine
Thyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.-Synthesis and regulation:...
and triiodotyronine contain iodine. In areas where there is little iodine in the diet—typically remote inland
areas where no marine foods are eaten—iodine deficiency gives rise to
goiter (so-called endemic goiter), as well as cretinism
Cretinism
Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones usually due to maternal hypothyroidism.-Etymology and use of cretin:...
, which results in developmental delays and other health problems.
While noting recent progress, The Lancet
The Lancet
The Lancet is a weekly peer-reviewed general medical journal. It is one of the world's best known, oldest, and most respected general medical journals...
noted, "According to WHO
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
, 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 mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
, is an important public-health
Public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
problem."
In some such areas, this is now combatted by the addition of small amounts of iodine to table salt in form of sodium iodide
Sodium iodide
Sodium iodide is a white, crystalline salt with chemical formula NaI used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.-Uses:Sodium iodide is commonly used to treat and prevent iodine deficiency....
, potassium iodide
Potassium iodide
Potassium iodide is an inorganic compound with the chemical formula KI. This white salt is the most commercially significant iodide compound, with approximately 37,000 tons produced in 1985. It is less hygroscopic than sodium iodide, making it easier to work with...
, and/or potassium iodate
Potassium iodate
Potassium iodate is a chemical compound. It is ionic, made up of K+ ions and IO3- ions in a 1:1 ratio.-Chemical properties:Potassium iodate is an oxidizing agent and as such it can cause fires if in contact with combustible materials or reducing agents...
—this product is known as iodized salt. Iodine compounds have also been added to other foodstuffs, such as flour, water and milk in areas of deficiency. Seafood
Seafood
Seafood is any form of marine life regarded as food by humans. Seafoods include fish, molluscs , crustaceans , echinoderms . Edible sea plants, such as some seaweeds and microalgae, are also seafood, and are widely eaten around the world, especially in Asia...
is also a well known source of iodine. Thus, iodine deficiency is more common in mountainous regions of the world where food is grown in soil poor in iodine.
Goiter
A low amount of thyroxineThyroxine
Thyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.-Synthesis and regulation:...
(one of the two thyroid hormones) in the blood, due to lack of dietary iodine to make it, gives rise to high levels of thyroid stimulating hormone TSH
TSH
TSH may refer to:* Tanzanian shilling, the currency of Tanzania* Thyroid-stimulating hormone, a hormone synthesized and secreted by thyrotrope cells* Tshiuetin Rail Transportation, a Canadian railway between Labrador and Quebec...
, which stimulates the thyroid gland to increase many biochemical processes; the cellular growth and proliferation can result in the characteristic swelling or hyperplasia of the thyroid gland, or goiter. In mild iodine deficiency, levels of triiodiothyronine (T3) may be elevated in the presence of low levels of levothyroxine, as the body converts more of the levothyroxine to triiodothyronine as a compensation. Some such patients may have a goiter, without an elevated TSH. The introduction of iodized salt since the early 1900s has eliminated this condition in many affluent countries; however, in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, and several Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an countries, iodine deficiency is a significant public health problem. It is more common in third-world nations. Public health initiatives to lower the risk of cardiovascular disease have resulted in lower discretionary salt use at the table, and with a trend towards consuming more processed foods. The noniodized salt used in these foods also means that people are less likely to obtain iodine from adding salt during cooking.
Goiter is said to be endemic when the prevalence in a population is > 5%, and in most cases goiter can be treated with iodine supplementation. If goiter is untreated for around five years, however, iodine supplementation or thyroxine treatment may not reduce the size of the thyroid gland because the thyroid is permanently damaged.
Cretinism
Iodine deficiency is one of the leading causes of preventable mental handicaps worldwide, producing typical reductions in IQIntelligence quotient
An intelligence quotient, or IQ, is a score derived from one of several different standardized tests designed to assess intelligence. When modern IQ tests are constructed, the mean score within an age group is set to 100 and the standard deviation to 15...
of 10 to 15 IQ points. It has been speculated that deficiency of iodine and other micronutrients may be a possible factor in observed differences in IQ between ethnic groups: see race and intelligence
Race and intelligence
The connection between race and intelligence has been a subject of debate in both popular science and academic research since the inception of intelligence testing in the early 20th century...
for a further discussion of this controversial issue.
Cretinism is a condition associated with iodine deficiency and goiter, commonly characterised by mental deficiency, deaf-mutism, squint, disorders of stance and gait, stunted growth and hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
. Paracelsus
Paracelsus
Paracelsus was a German-Swiss Renaissance physician, botanist, alchemist, astrologer, and general occultist....
was the first to point out the relation between goitrous parents and mentally retarded children.
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 deficiency. Diderot
Denis Diderot
Denis Diderot was a French philosopher, art critic, and writer. He was a prominent person during the Enlightenment and is best known for serving as co-founder and chief editor of and contributor to the Encyclopédie....
, in his 1754 Encyclopédie
Encyclopédie
Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers was a general encyclopedia published in France between 1751 and 1772, with later supplements, revised editions, and translations. It was edited by Denis Diderot and Jean le Rond d'Alembert...
, described these patients as "crétins". In French, the term "crétin des Alpes" also became current, since the condition was observed in remote valleys of the Alps
Valleys of the Alps
-Rhine basin :High Rhine*Aare**Limmat***Linth ****Lake Walen*****Seez****Klöntal****Sernftal**Reuss River***Lake Lucerne****Sarner Aa ****Muotathal***Schächen, Klausen Pass connects to Glarus...
in particular. The word cretin appeared in English in 1779.
Deficiency
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.Iodine deficiency is the leading cause of preventable mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations, but as of March 2006, iodine deficiency remained a serious public health problem in the developing world. Iodine deficiency is also a problem in certain areas of Europe. In Germany it has been estimated to cause a billion dollars in health care costs per year.
Iodine may also help prevent diseases of the oral and salivary glands.
Extrathyroidal iodine
Iodine accounts for 65% of the molecular weight of T4 and 59% of the T3. 15–20 mg of iodine is concentrated in thyroid tissue and hormones, but 70% of the body's iodine is distributed in other tissues, including mammary glands, eyes, gastric mucosa, the cervix, and salivary glands. In the cells of these tissues iodide enters directly by sodium-iodide symporterSodium-iodide symporter
The sodium/iodide symporter , also known as solute carrier family 5, member 5 is a protein that in humans is encoded by the SLC5A5 gene. The sodium/iodide symporter is a transmembrane glycoprotein with a molecular weight of 87 kDa and 13 transmembrane domains, which transports two sodium cations ...
(NIS). Its role in mammary tissue is related to fetal and neonatal development, but its role in the other tissues is unknown. It has been shown to act as an antioxidant in these tissues.The US Food and Nutrition Board and Institute of Medicine recommended daily allowance of iodine ranges from 150 micrograms /day for adult humans to 290 micrograms /day for lactating mothers. However, the thyroid gland needs no more than 70 micrograms /day to synthesize the requisite daily amounts of T4 and T3. These higher recommended daily allowance levels of iodine seem necessary for optimal function of a number of body systems, including lactating breast, gastric mucosa, salivary glands, oral mucosa, thymus, epidermis, choroid plexus, etc.
Moreover, iodine can add to double bonds of docosahexaenoic acid
Docosahexaenoic acid
Docosahexaenoic acid is an omega-3 fatty acid that is a primary structural component of the human brain and retina. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end...
and arachidonic acid
Arachidonic acid
Arachidonic acid is a polyunsaturated omega-6 fatty acid 20:4.It is the counterpart to the saturated arachidic acid found in peanut oil, Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6).It is the counterpart to the saturated arachidic acid found in peanut oil,...
of cellular membranes, making them less reactive to free oxygen radicals.
Iodine deficiency and cancer risk
- Breast cancerBreast cancerBreast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
. The breast strongly and actively concentrates iodine into breast-milk for the benefit of the developing infant, and may develop a goiter-like hyperplasia, sometimes manifesting as fibrocystic breast disease, when iodine levels are low. Studies indicate that iodine deficiency, either dietary or pharmacologic is a risk factor for breast cancer and can lead to breast atypiaAtypiaAtypia is a clinical term for abnormality in a cell. The term is medical jargon for an atypical cell. Atypia: Etymology: Gk, a + typos, without type; a condition of being irregular or nonstandard....
and increased incidence of malignancy in animal models, while iodine treatment can reverse dysplasiaDysplasiaDysplasia , is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process...
. Laboratory evidences demonstrate that the effect of iodine on breast cancer is in part independent of thyroidThyroidThe thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
function and that iodine inhibits cancer promotion through modulation of the estrogenEstrogenEstrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
pathway. Gene array profiling of estrogen responsive breast cancer cell line shows that the combination of iodine and iodide alters gene expression and inhibits the estrogen response through up-regulating proteins involved in estrogen metabolism. Whether iodine/iodide will be useful as an adjuvant therapy in the pharmacologic manipulation of the estrogen pathway in women with breast cancer has not been determined clinically.
- Iodine and stomach cancerStomach cancerGastric cancer, commonly referred to as stomach cancer, can develop in any part of the stomach and may spread throughout the stomach and to other organs; particularly the esophagus, lungs, lymph nodes, and the liver...
. Some researchers have found an epidemiologic correlation between iodine deficiency, iodine-deficient goitre and gastric cancer; a decrease of the incidence of death rate from stomach cancer after implementation of the effective iodine-prophylaxis has been reported also. The proposed mechanism of action is that iodide ion can function in gastric mucosa as an antioxidant reducingRedoxRedox reactions describe all chemical reactions in which atoms have their oxidation state changed....
species that can detoxify poisonous reactive oxygen speciesReactive oxygen speciesReactive oxygen species are chemically reactive molecules containing oxygen. Examples include oxygen ions and peroxides. Reactive oxygen species are highly reactive due to the presence of unpaired valence shell electrons....
, such as hydrogen peroxideHydrogen peroxideHydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
.
Epidemiology
Certain areas of the world, due to natural deficiency and unavailability of iodine, are severely affected by iodine deficiency, which affects approximately two billion people worldwide. It is particularly common in the Western PacificPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, South-East Asia and Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
.
India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
is the most outstanding, with 100 million suffering from deficiency, 4 million from goiter, and 0.5 million from cretinism
Cretinism
Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones usually due to maternal hypothyroidism.-Etymology and use of cretin:...
.
Among other nations affected by iodine deficiency, China and Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
have begun taking action, while Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
has not. Successful campaigns for the adoption of the use of iodized salt require education of salt producers and sellers and a communication campaign directed at the public. The cost of adding iodine to salt is negligible—"Only a few cents a ton."
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. A proposal to mandate the use of iodized salt in most commercial breadmaking is expected to be adopted in 2009. In a study of the United Kingdom published in 2011, almost 70% of test subjects were found to be iodine deficient. The study's authors suggested an investigation regarding "evidence-based recommendations for iodine supplementation".
Risk factors
Following is a list of potential risk factors that may lead to iodine deficiency:- Low dietary iodine
- Selenium deficiencySelenium deficiencySelenium deficiency is relatively rare in healthy well-nourished individuals. Few cases have been reported.-Causes:It can occur in patients with severely compromised intestinal function, those undergoing total parenteral nutrition, those who have had gastrointestinal bypass surgery, and also on...
- PregnancyPregnancyPregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
- Exposure to radiationRadiation exposureThe term radiation exposure commonly has several uses:* Absorption of high-energy ionizing radiation by an object. In living beings a high absorbed dose can lead to radiation poisoning.* Absorption by an object of non-ionizing radiation...
- Increased intake/plasma levels of goitrogenGoitrogenGoitrogens are substances that suppress the function of the thyroid gland by interfering with iodine uptake, which can, as a result, cause an enlargement of the thyroid, i.e., a goitre.-Goitrogenic drugs and chemicals:...
s, such as calcium - Gender (higher occurrence in women)
- Smoking tobacco
- AlcoholAlcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
(reduced prevalence in users) - Oral contraceptives (reduced prevalence in users)
- PerchloratePerchloratePerchlorates are the salts derived from perchloric acid . They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a...
s - ThiocyanateThiocyanateThiocyanate is the anion [SCN]−. It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Organic compounds containing the functional group SCN are also called thiocyanates...
s - Age (for different types of iodine deficiency at different ages)
Diagnosis
The diagnostic workup of a suspected iodine deficiency includes signs and symptoms as well as possible risk factors mentioned above.In addition, a 24-hour urine iodine collection is a useful medical test
Medical test
A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease. For example:* to diagnose diseases, and preferably sub-classify it regarding, for example, severity and treatability...
, as approximately 90% of ingested iodine is excreted in the urine. If a 24-hour urine collection is not practical, a random urine iodine-to-creatinine ratio can alternatively be used.
Treatment
Iodine deficiency is treated by ingestion of iodine, such as found in food supplements. Mild cases may be treated by using iodized salt in daily food consumption, or eating more of milk, egg yolks, and saltwater fish.In an adult, 150 µg
Microgram
In the metric system, a microgram is a unit of mass equal to one millionth of a gram , or 1/1000 of a milligram. It is one of the smallest units of mass commonly used...
/d is sufficient for normal thyroid function.
Prognosis
With iodine supplementation, goiters caused by iodine deficiency decrease in size of in very young children and pregnant women. Generally, however, long-standing goiters caused by iodine deficiency respond with only small amounts of shrinkage after iodine supplementation, and patients are at risk for developing hyperthyroidismHyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
.