Iodine deficiency

Iodine is an essential trace element; the thyroid hormones 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 goitre), as well as cretinism, which results in developmental delays and other health problems.

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, potassium iodate—this product is known as iodized salt. Iodine compounds have also been added to other foodstuffs, such as flour, in areas of deficiency. Seaweed is also a well known source of iodine^[1].

A lack of Iodine in the human body can result in Gout. This I-defiency is more common in mountainous regions of the world where food is grown in poor soil.

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Goitre

Main article: Goitre

Low amounts of thyroid hormones in the blood, due to lack of iodine to make them, give rise to high levels of the pituitary hormone TSH, which in turn stimulate abnormal growth of the thyroid gland, sometimes causing goitres. Iodized salt and other sources of iodine in the diet has eliminated this condition in many affluent countries, however there are a number of European countries, Australia, and New Zealand where iodine deficiency is a significant public health problem (Andersson M, Takkouche B, Egli I, Allen HE, de Benoist B. Current global iodine status and progress over the last decade towards the elimination of iodine deficiency. Bull World Health Organ 2005;83:518-25). However, it is still common in poorer nations. Also, treatment for conditions such as hypertension proscribe the excessive intake of salt and prescribe the use of a salt substitute.

Cretinism

Main article: Cretinism

Iodine deficiency is the leading cause of mental retardation, producing typical reductions in IQ 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 goitre, commonly characterised by mental deficiency, deaf-mutism, squint, disorders of stance and gait, stunted growth and hypothyroidism. "Chretien" is old French for Christian. Refugees settled in the Pyrenees and because of persecution retired into remote valleys. 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. The term "chretien" for this kind of Christian seems to have developed as a term of contempt and was applied to other children of the same kind in other localities. Paracelsus was the first to point out the relation between goitrous parents and children who were cretins. The word appeared in English in 1779.

Local impact

Certain areas of the world, due to natural deficiency and governmental inaction, are severely affected by iodine deficiency, which effects approximately two billion people worldwide. It is particularly common in the Netherlands, Western Pacific, South-East Asia and Africa.

India is the most outstanding, with 500 million suffering from deficiency, 54 million from goitre, and two 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 and regulation of salt producers and sellers and a communication campaign directed at the public, the salt trade, politicians and policy makers. The cost of adding iodine to salt is negligible. ^[2]

See also

• Basil Hetzel
• Lugol's iodine

References

1. ^ http://seaweed.ucg.ie/Nutrition/iodine.html
2. ^ "In Raising the World’s I.Q., the Secret's in the Salt", article by Donald G. McNeil, Jr., December 16, 2006, New York Times