Iodine in the human body


Iodine (scientific notation: iodine) is a trace element that is necessary in the body for the production of thyroid hormones. The thyroid hormones play an important role in growth and development. It is therefore important that enough iodine is absorbed through food. Natural sources include sea fish and marine animals, for example. In the German population, however, too little iodine is absorbed through these foods, so that iodized table salt is used in food production. Salt containing iodine should also be used in the household. An iodine deficiency can lead to various diseases of the thyroid, such as the so-called goiter (Goiter), which is an enlargement of the thyroid gland.


The main function of iodine in the human body is to be the essential building material for the thyroid hormones. These are called T3 (Triiodothyronine) and T4 (Tetraiodothyronine). T4 is also known as thyroxine. The iodine supplied with food is absorbed by the thyroid gland. This is where the hormones are produced and released into the blood. In this way it fulfills important tasks in growth and development, for example the bones and the nervous system as well as the metabolism. Without iodine, the body could not function properly in many areas.
A sufficient supply of iodine is also important, as this directly counteracts excessive growth of the thyroid. Possible diseases and functional disorders of the thyroid gland can also be prevented in this way.
Scientific studies have also shown that the body uses iodine in tear fluid and other secretions to kill germs and thus protect against infections.

Read more on the topic: T3 and T4 hormones


As a central part of the Hormones produced by the thyroid gland are produced, iodine fulfills a variety of functions in the human body. This is made possible by the direct influence of hormones on the function of almost all cells in the body.
The iodine supplied with food is absorbed through the intestine and arrives in the blood thyroid. There it absorbs the iodine and, together with proteins, forms the thyroid hormones. These are stored in the gland and released into the blood as the body needs. There they are bound to certain transport proteins. After leaving the thyroid, the iodine-containing hormones arrive with the blood in all areas of the body and take effect in the cells. As an essential component of thyroid hormones, the trace element iodine is an indispensable factor for Growth, development and metabolism. An essential task is the regulation of normal heat generation in the body. People with a underactive thyroid tend to freeze quickly while having one Hyperthyroidism heat intolerance occurs. The thyroid hormones are also very important for bone metabolism and the development of new bone substance. Especially in children, iodine in the form of the thyroid hormones is an important factor for normal development, especially of the brain and nervous system. That is why it is mainly in the pregnancy and breast feeding period a adequate iodine supply especially important to the mother in order to enable the child's healthy development. Furthermore, the iodine-containing hormones, among many others, are essential in the regulation of Blood pressure, heart rate and heart strength involved. Also the Kidney function is being influenced.

What if iodine is missing?

Iodine deficiency leads to various diseases of the thyroid gland and can due to the important role of the thyroid gland in various body functions serious health problems to lead. The most common cause of iodine deficiency is one Enlargement of the thyroid gland and with it a swelling of the neck, which as Goiter or even medically Goiter referred to as. This can lead to necklaces and clothing becoming too tight on the collar. It can continue to difficulties swallowing and in extreme cases even such an impediment to breathing can occur when the growing thyroid tissue presses on the windpipe. This can lead to uniform growth, but also to the formation of single or multiple lumps on the neck.
Another disease caused by insufficient iodine intake is that Thyroid autonomy. This leads to an uncontrolled production of thyroid hormones and thus to hyperfunction. This Overactive can be manifested by various symptoms such as internal restlessness, increased sweating, intolerance to heat, tremors and diarrhea. Elderly people in particular can experience heart problems and increased bone loss. Often enough the hormone production of the autonomic thyroid tissue but not off to lead to hyperfunction. One speaks of a compensated autonomy and the illness can last for a long time undetected stay.
The risk for Thyroid cancer is also increased with iodine deficiency.
Especially momentous is Iodine deficiency in the Development of newborns and young children. This can lead to impairments in physical and mental development, in extreme cases to disabilities with reduced intelligence, short stature and deafness. This as cretinism Described undesirable development is nowadays in Germany due to the Screening newborns for thyroid disease and the Iodine prophylaxis fortunately very much in food Rare become.

How can you measure iodine in the body?

A direct measurement of iodine in the body is usually made Not performed. The iodine excretion in the urine is only measured in large population studies on the supply of iodine in order to enable conclusions to be drawn about iodine uptake. Since too low or too high iodine values ​​almost only affect the thyroid gland, it is easier and more useful to examine their function and structure. If a doctor suspects that complaints and abnormalities expressed by a patient during the physical examination could be caused by a malfunction of the thyroid gland, a thyroid-specific laboratory value, of the "TSH" means, definitely. This value can be used to assess whether the thyroid function is normal. If this is not the case, a further determination can be made, for example the Thyroid hormones or from Thyroid antibodies. If there is any suspicion that a Thyroid disease is available, an Assessment of thyroid size and structure using a Ultrasound examination. An enlarged thyroid as a sign of one Iodine deficiency can thus be recognized early and, if necessary, treated with iodine tablets, for example. In addition, ultrasound can also be used Thyroid nodules that are often not noticeable during the palpation examination. Whether these are benign or malignant and whether therapy should be given can, if necessary, be determined by further special examinations.

How can you neutralize iodine in the human body?

A contrast agent containing iodine is sometimes used during a CT scan.

In contrast to iodine deficiency is a Excess rarely. In any case, iodine almost exclusively affects the thyroid gland, which has various mechanisms to protect itself against an excess of iodine. For these reasons, iodine must also Not in the human body neutralized become. Rather, iodine is a important trace elementwhich the body to Maintenance many functions are required. There are several Regulatory mechanisms, through which the body counteracts a deficiency or excess, for example through the admission of iodine from food im Intestines or about the excretion via the kidney to the urine. An excess of iodine often only occurs during a CT examination using an iodine-containing contrast agent.
However, treatment of excess iodine is only required if Previously unnoticed thyroid disease was presentwhich occurs through the high amount of iodine in the body. But even in this case iodine is not neutralized directly, but rather through the use of drugs Hormone production slowed down and thus the Effects of the excess treated.

How can i lower iodine in the body?

Directly lowering the iodine level in the body not possible, but also unnecessary. The body regulates the iodine content through various mechanisms. So can the admission of iodine im Intestines and the excretion through the kidney in the urine be increased and decreased. Furthermore, the thyroid can store large amounts of iodine without being damaged. If there is an oversupply, she can use a Blocking the admission protect and the excess iodine is simply excreted through the kidneys without harming the body. However, if there is a disease of the thyroid gland, excessive iodine intake can lead to a Hyperfunction to lead. However, the iodine contained in the food and in the iodized salt is not sufficient for such an increase in iodine; rather, very large amounts of iodine are required for a CT examination, for example through iodine-containing contrast media. Even then, there is no direct lowering of iodine in the body, but one Therapy of the resulting overactive thyroid. The iodine is released into the urine via the kidneys and excreted.

How is iodine stored in the human body?

The only organ in the body that contains iodine recovered, is the thyroid. That is why it is mainly bound to proteins and stored there. If necessary, the body uses the supply there to produce and release thyroid hormones. So much iodine is stored in the thyroid gland that if it is not consumed, it will be needed for up to 3 months can be sustained. To a certain extent can also Iodine is stored in adipose tissue become. However, it is not processed further there.