Iodine deficiency

Iodine deficiency occurs in humans, when the body through food or drinking water supply without further receives too little iodine with trace elements. Iodine is almost exclusively required for the construction of the thyroid hormones. The thyroid gland may in good supply ten milligrams of iodine stockpile, this corresponds to the requirement of iodine for three months.

Recommended daily intake of iodine

The German Nutrition Society ( DGE) recommends the daily intake of 180 to 200 micrograms of iodine per day for adults ( pregnant women and nursing mothers a little more ) and 40 to 200 micrograms for children and adolescents. The actual iodine intake in Germany was estimated by the DGE 2003 110-120 micrograms iodine / day in adults.

Causes and Epidemiology of iodine deficiency

• No data
• Below 50
• > 50-100
• > 100-150
• > 150-200
• > 200-250
• > 250-300
• > 300-350
• > 350-400
• > 400-450
• > 450-500
• > 500-800
• About 800

In Central Europe the agricultural soils are relatively low in iodine. This applies not only for the Alpine region, but also for the soils of the coastal plains in Denmark and the Netherlands. The soils of humid climates are so so poor in iodine, because it was washed out in the course of the earth. The iodine content in the secondary environmental water and soil is subject to many factors. Sea distance, mountainous regions, however, are more likely affected by iodine deficiency than the lowlands. In Europe, these were traditionally the Alpine countries and the Balkans. In North America, it was especially the areas around the Great Lakes.

On the part of WHO, it is estimated that about 750 million to one billion people are affected by iodine deficiency worldwide. In Western and Central Europe, this affects more than 380 million people.

The thyroid can absorb about 40 % of ingested iodine from the blood and accumulate. The rest is excreted by the kidneys. The amount of iodine which is excreted in urine every day, is a good measure of the iodine of the organism. The measured value of the daily iodine excretion related to creatinine, a metabolic waste product, which is also excreted in the urine; so you can get an age- independent parameters. The setpoint is by recommendation of the DGE 150 micrograms / g creatinine. The World Health Organization ( WHO) classifies iodine deficiency and excess supply follows a

Symptoms and consequences of iodine deficiency

Iodine is an essential trace element and mainly for thyroid function important. The thyroid gland also synthesizes the essential iodine-containing hormones thyroxine ( thyroxine, T4) and triiodothyronine ( T3). A chronic lack of iodine leads initially to hyperplasia and hypertrophy later, that is, to increase in size of the thyroid gland. Clinically, it makes as goiter ( Medical: goiter) noticeable. The endemic goiter was in earlier centuries almost the hallmark of entire populations, for example in Bavaria, Switzerland and Austria. If the iodine deficiency extended period of time, a nodular goiter may develop with autonomous adenomas. If the iodine deficiency situation resolved then suddenly (eg by increased supply with the diet or by administration of highly iodinated X-ray contrast agents ), by excessive hormone production by the autonomous areas of hyperthyroidism ( overactive thyroid ) can develop.

The T3 and T4 hormones are crucial for early childhood brain development. An existing at birth marked deficiency of these hormones leads to more or less severe mental retardation ( up to cretinism ). Hence, every newborn is routinely for the presence of hypothyroidism ( underactive thyroid ) investigated to treat this as soon as possible. If treatment is delayed by a few weeks, this may have an intellectual disability the result that no longer makes possible a later higher education. The most common cause of hypothyroidism in the newborn is the insufficient iodine intake during pregnancy. Therefore, the adequate iodine intake is just in pregnancy is of particular importance. A meta-analysis of ten different studies showed that a chronic lack of iodine in a mean intelligence quotient reduction by 13.5 points led. The fact that chronic iodine deficiency in children leads to mental retardation, has been confirmed by studies from all over the world. Iodine deficiency is considered to be the largest single cause of preventable brain damage and mental retardation.

Prevention

In ancient China, doctors recommended the consumption of algae and sponges. When the supply of seaweed but care must be taken to an exact dosage, otherwise an overdose with over 500 micrograms per day is easily possible. The marine fish in Europe is the most commonly available foods with the highest content of iodine ( haddock about 240 micrograms per 100 grams or herring approximately 50 micrograms in 100 g). Since the 19th century pure iodide is available. In meat products, dairy products, bread, ready meals, canteen food and commercial table salt is added on a voluntary basis to increase iodine intake. Iodized salt contains 20 micrograms of iodine per gram of Germany salt in the form of potassium iodate; in Switzerland, the concentration is not higher than in Germany - but the proportion of iodine salt in commercial foods ( Switzerland: 70%, Germany: 30% ). In addition, the animal feed is iodized in several countries, including Germany. Limits defines the EU. The domestic quantity of iodized salt increased iodine intake of consumers by about 20 micrograms daily, added iodine in processed foods and meat products, which varies greatly.

An adequate iodine intake of 150 to 200 micrograms per day is in shortage areas such as Germany thus through the careful consumption of iodine-rich foods such as fish or sea food supplements (such as seaweed preparations ) possible. Similarly, the intake of iodine tablets is possible. A harmful overdose occurs at a dose of 500 micrograms or more per day.

In areas where salt iodization is not possible, can be supplemented with an enriched with iodine oil capsule in one-or two -year cycle. This is usually the case in developing countries, when the salt supply is decentralized, or done the salt extraction private.

A statutory iodine prophylaxis is available in Taiwan, Switzerland, Austria, the USA, until the reunification in the GDR. In the united Germany, the legislature is voluntary.

Situation in Germany

Numerous epidemiological work of the last decades show the natural iodine deficiency in Germany. The largest study (about 6000 people ) was developed by Hampel et al. 1993-1994 collected and submitted in 1995. The average urine iodine excretion was 72 micrograms of iodine per gram of creatinine. Only nine percent of the subjects were adequately supplied with more than 150 ug / g with iodine. 17 % had a lack of iodine from grade 0 (WHO ), 25% grade I, 17 % grade II and 2% grade III. Inhabitants of the coastal regions had no higher urinary iodine than the inhabitants of the highlands and the foothills of the Alps.

The shortage still led in the late 1990s in Germany annually to 100,000 thyroid operations. Iodized salt was indeed already available since 1959, but initially admitted to 1981 only for medical treatments. Only in 1989 it was included in the additive authorization regulation and also reduces the declaration requirements for producers in the following years.

Through the public relations work of the Federal Centre for Health Education and financed by industry working group iodine deficiency and the increasing use of jodangereichertem table salt in households ( 83%) in commercial kitchens and in the food industry ( 29%), urinary iodine has since increased significantly according to recent studies, especially in children. Comprehensive data are not yet available, but is expected to high regional and individual variations due to the voluntary nature of such measures. The most recent studies still show a high proportion of underserved people. The measurements of Hampel et al. 2001 3000 school children from 128 cities in Germany showed, for example, a mean urinary iodine of 148 ug / g, but 27% still had an iodine deficiency grade I or worse. A WHO report grouped Germany in 2003 as optimal care (except for pregnant and lactating women ). According to the guidelines of the WHO every five years comprehensive data should be collected for iodine intake. This is done in Germany in 1996 and 2006.

For the current epidemiological situation of iodine intake of children and adolescents Results are available from the Child and Adolescent Health Survey of the Robert Koch Institute: ioduria median of 117 ug / l The pharmaco-epidemiological situation of the use of thyroid preparations of adult and serum levels of thyroid hormones triiodothyronine, thyroxine and TSH is in a GBE publication from the population-representative data of the RKI Health Survey: shown ( see Web report by the Robert Koch Institute ).

In a study from the year 2005 (2009 published) indeed showed 64% of the persons examined a sufficient iodine excretion, but 23% mild, 10 % moderate and 3% a severe iodine deficiency. The authors saw the causes of improved iodine supply, especially in the higher iodine content of milk and dairy products, as well as the widespread use of iodized salt in restaurants. The food industry is not yet used sufficiently often iodized salt.

Problems

Showed data from the countries with legally mandatory salt iodization as Austria, it in amplification of autoimmune thyroid disease may occur (eg, Graves' disease ) during the first years after the introduction at higher iodination. An optimal prophylaxis should therefore demand, ie avoiding an oversupply done and be carefully monitored epidemiologically. Patients with such conditions should be identified early and treated.

Critics of the iodization as the journalist Udo Pollmer indicate that the manufacturer is liable for any damage to consumers under the product liability law. Do not criticize while the high iodine content of marine fish, but the Tierfutterjodierung, which has increased the iodine content of dairy products of milk and eggs stronger in some countries, without that consumers are made aware. To prevent damage to health, the European Food Safety Authority suggested to restrict the allowed iodization of animal feed, so ultimately the people. Then by EU regulation Nr.1459/2005 the ceilings for the iodization of animal feed for chickens and cows were halved. In the EU has tried to include the entire iodine intake of the man who stands at the end of the food chain. At full Maximization of the current limit (5 mg / kg) and exclusive concentrate feeding doses of 400-1200 ug / l, however, are still possible in cow's milk, which corresponds to a daily intake of one liter of cow's milk to a multiple of the recommended daily dose. In Germany, the iodine content of concentrates is only 1 mg / kg with an average of 50 % concentrate fraction ( with resultant average milk iodine content of 100 g / l).

Stiftung Warentest certain milk in a large test even the milk iodine content. He lay between 30 and 180 ug / l, organic milks spending in the lower third of this range. The World Health Organization warns of a median value of about 300 micrograms iodine / l urine from negative health consequences.