Iodine developing countries

Iodine deficiency in less developed countries is still a serious problem. Whereas, iodized and iodated salt technology is readily available and relatively inexpensive, market distribution conditions, as well as a lack of understanding by consumers, prevents iodized salt from reaching much of the population in less-developed countries. 

Globally, undernutrition is widespread, leading to impaired growth, defective immune systems, and reduced work capacity. By contrast, in developed countries, there is often excessive food consumption (especially of fat), leading to obesity and to the development of cardiovascular disease and some forms of cancer. Deficiencies of vitamin A, iron, and iodine pose major health concerns in many countries, and deficiencies of other vitamins and minerals are a major cause of iU health. In developed countries, nutrient deficiency is rare, though there are vulnerable sections of the population at risk. Intakes of minerals and vitamins that are adequate to prevent deficiency may be inadequate to promote optimum health and longevity. 

Low iodine levels can be easily corrected. In most developed countries today, companies that make table salt add a small amount of potassium iodide (Kl) to their salt. The salt is labeled "iodized salt." People who use iodized salt get all the iodine they need for normal thyroid function. 

Primary goitrous hypothyroidism results when the synthesis of T4 and T3 is impaired, either because of some extrinsic factor or because of an intrinsic, inherited defect in thyroid hormone biosynthesis. As a result, the positive feedback loop causes compensatory thyroid enlargement (goiter) through the hypersecretion of TRH and TSH. Primary nongoitrous hypothyroidism is characterized by loss or atrophy of thyroid tissue, resulting in decreased production of thyroid hormones despite maximum stimulation by TSH. Hashimotos thyroiditis is the most frequent cause of primary hypothyroidism in developed countries where iodine intake is sufficient. Worldwide, iodine deficiency is the most common cause of goitrous hypothyroidism. The... 

In developed countries, where iodine deficiency is rare because of the use of iodized salt, autoimmune disorders are a leading cause of thyroid disease. 

Without iodine supplements in the form of marine fishmeal or mineral mixtures, the farm animals of most countries worldwide would suffer of iodine deficiency. Germany and most industrially developed countries unconsciously supply farm animals (and in turn the population) with iodine by fertilizing the land with Chile saltpeter, which has a high iodine content. During World War I, the importation of Chile saltpeter to Europe was stopped, and thereafter synthetic nitrogen containing no iodine was produced worldwide. Consequently, iodine deficiencies in both animals and man reap-... 

Table 2.8 presents another example of marked differences of iodine levels in daily diet samples in different countries, using the results achieved within a WHO and IAEA coordinated research project on dietary intake of several important minor and trace elements in diets consumed in a number of developed and developing countries (Dermelj etal., 1990). 

Iodine intake depends on food choice. In many developed countries, a high intake of milk is the main determinant of iodine intake, whereas fish intake is less important. However, in countries or populations with a tradition of a high fish intake, or especially of a high intake of seaweed, the iodine intake is high. Furthermore, iodine intake... 

The major natural food source of iodine is fish. The iodine content of fish reflects that of the water they inhabit thus, high levels of iodine are present in marine fish and shellfish compared to freshwater fish (Figure 45.1). Milk and dairy products contain relatively high amounts of iodine and are considered to be the most important sources of iodine in developed countries. The iodine content of milk is largely influenced by the use of iodophors as teat sterilants and equipment sanitizers in dairy husbandry, and the supplementation of animal feeds due to iodine deficiency in dairy cattle, exacerbated by the inclusion of goitrogenic feeds in the diet (COT, 2003). In addition, seasonal variations in the iodine content of foods are particularly evident in cows milk, with greater iodine... 

Possible dietary sources of iodine for vegans include iodized salt and seaweed (Lightowler and Davies, 1996). In many developing countries, iodized salt is considered a good medium for iodine prophylaxis. However, although some iodized salt contains 1527-25 57 fig/lOOg (equivalent to 76-128 pg/teaspoon), encouragement to use this... 

In summary, it seems that the number of people who consistently follow strict vegetarian diets is small, probably less than 0.1% of the populations in the US and European countries there is a lack of data on the numbers who adhere to such diets in developing countries. These are the vegetarians most likely to be iodine-deficient. By contrast, a substantial proportion of self-identified vegetarians regularly consume iodine-rich dairy products and a smaller proportion eat meat, poultry, or fish at least occasionally. 

Early correction of hypothyroidism due to congenital defects in neonates has now become a standard practice in most developed countries in order to prevent longterm brain damage (Dussault and Glorieux, 1989). The more severe the fetal hypothyroidism, as indicated by bone retardation, the more Hkely are residual effects (Dussault and Glorieux, 1989). Such considerations indicate the urgent need for a preventive approach to the correction of iodine deficiency for developing countries, because treatment of individual cases is not usually possible. 

Pregnant Women with Iodine Deficiency in Iodine-Sufficient Areas How Common is Hypothyroxinemia in Pregnant Women in Developed Countries ... 

Iodine deficiency is the most common cause of hypothyroidism worldwide, but it is uncommon in developed countries where there is sufficient intake of iodine in the diet (Delange, 1998 Delange etal., 2001). Iodine administtation is another cause of thyroid hypofunction (AUen et al., 1986 ... 

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