Potassium iodate, iodine deficiency

Iodized Salt. Iodized table salt has been used to provide supplemental iodine to the U.S. population since 1924, when producers, in cooperation with the Michigan State Medical Society (24), began a voluntary program of salt iodization in Michigan that ultimately led to the elimination of iodine deficiency in the United States. More than 50% of the table salt sold in the United States is iodized. Potassium iodide in table salt at levels of 0.006% to 0.01% KI is one of two sources of iodine for food-grade salt approved by the U.S. Food and Dmg Administration. The other, cuprous iodide, is not used by U.S. salt producers. Iodine may be added to a food so that the daily intake does not exceed 225 p.g for adults and children over four years of age. Potassium iodide is unstable under conditions of extreme moisture and temperature, particularly in an acid environment. Sodium carbonate or sodium bicarbonate is added to increase alkalinity, and sodium thiosulfate or dextrose is added to stabilize potassium iodide. Without a stabilizer, potassium iodide is oxidized to iodine and lost by volatilization from the product. Potassium iodate, far more stable than potassium iodide, is widely used in other parts of the world, but is not approved for use in the United States. 

Potassium iodide and potassium iodate are commonly added to table salt to prevent iodine deficiency and associated thyroid disease. 

As grains do not derive much iodine from the soil, the iodine content of cereal products is mainly due to the addition of potassium and calcium iodate used as stabilizers in baking. Moreover, the addition of iodate to bread in some countries is specifically for the prevention of iodine deficiency (Dunn, 1993). 

Lack of iodine interferes with the synthesis of the main hormonal product of the thyroid gland, thyroxine, a complex organic molecule containing four atoms of iodine (Figure 94.1). The elimination of iodine deficiency is usually achieved by adding iodine 20-80 mg/kg salt in the form of a sodium or potassium salt of iodide or iodate, the latter being preferred because of its better stability (Kelly, 1953 Arroyave 4/., 1956). 

Iodine is introduced into the body mostly through food, iodized salt, and also drinking water and milk. Dietary iodine is found in the form of iodide or iodate of potassium, calcium, or sodium (Venkatesh and Dunn, 1995). When iodine requirements are not met, the production of thyroid hormones is reduced and the thyroid gland enlarges to compensate for this reduction. In adults, mild iodine deficiency is associated with nontoxic nodular goiter and, less often, with toxic nodular goiter because the constitutive (thyrotropin-independent) growth and the functional potential of some clones of thyroid cells increase. 

In 1997, with the closure of the Brazilian Nutrition and Food Institute (INAN), the National Program for Iodine Deficiency Disorder Control was terminated. The purchase, distribution and control of lodization of salt was then distributed to several organizations within the Ministry of Health, leading to complaints from the Brazilian Association of Salt Producers about disruptions in the provision of potassium iodate (Medeiros-Neto, 1998). 

Unfortunately, these simple protective measures are not implemented everywhere in the world. In India, an estimated 250,000,000 people suffer from iodine deficiency and the accompanying lethargy and decrease in motor skills and mental acuity. About nine million babies are bom with cretinism annually. Salt is often sold in big chunks, because in this form it resists humidity better. The only way to iodize the salt chunks is to spray them with a solution of potassium iodate. This, though, makes the large salt crystals look dirty, so people often wash them off before crushing them. They don t realize that cleanliness is not always a virtue. 

Potassium iodate, KIO3, the most thermodynamically stable and naturally occurring compound of polyvalent iodine, has found some application as a dietary supplement and a food additive. It can be used as a source of iodine in iodized salt and also as a dough conditioner [3]. In fact, because potassium iodate is more stable than iodide in the presence of air, most health authorities preferentially recommend iodate as an additive to salt for correcting iodine deficiency. Iodate is rapidly reduced to iodide in the body iodide is essential for thyroid function. However, high levels of iodate (0.600 mg per day) have been shown to cause damage to the retina, resulting in ocular toxicity [4]. The recommended level of iodine in iodized salt is between 20 and... 

Iodized Oil Iodine in poppy seed oil-lipiodol is extensively used in radiology as a radio-contrast medium to demonstrate holes (cavities) in the lung. Available both by injection (lipiodol) and by mouth (oriodol) for the instant correction of iodine deficiency Iodized Salt Salt to which potassium iodate or potassium iodide has been added at a recommended level of 20—40 milligrams of iodine per kilogram of salt Kiwanis International A World Service Group including more than 10,000 clubs and over 500,000 members based in the USA... 

The proportion of iodine in Simple Solution of Iodine, B.P.C. (containing 9 per cent W v of iodine), decreases rapidly on standing, owing to interaction of the iodine with the alcohol, and free hydriodic acid is formed. h"quilibrium is reached in up to eight months and the mixture then contains about 80 per cent of the original iodine in the uncombined state (Page ). Even alcoholic solutions of iodine containing potassium iodide, if old or deficient in potassium iodide, develop hydriodic acid, and the apparent amount of potassium iodide as estimated by the official method is increased. All samples therefore, should be examined for the presence of hydriodic acid and the iodate titration corrected before the proportion of potassium iodide is calculated. 

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