Iodine has been introduced into medical practice since 1820. This minor component plays a major role in the functioning of the thyroid gland.
Iodine can also be found in the blood, where its content is almost constant. The blood plasma contains 35% of the total amount of blood iodine, the remaining 65% are formed by blood elements. If you introduce a significant amount of inorganic iodine salts with food into the body its level in the blood will increase 1,000 times but 24 hours later it will return to normal. During the day, 100-300 µg of hormonal iodide enter the blood from the thyroid gland. The organic form is mainly represented by thyroxine. About 10% of organic plasma iodine is represented by triiodothyronines and diiodothyrosines.
The content of iodine in the blood with its normal intake into the body is 10–15 µg/l, while the total extracellular iodine reserve is 250 µg.
The micro-component is a biostimulant and immunostimulant, prevents an increase in blood clotting and the formation of blood clots.
Iodine enters our body mainly through the digestive tract. Inorganic iodine compounds are absorbed almost along the entire length of the gastrointestinal tract, but most intensively in the small intestine. Iodine intake occurs through the lungs as well, especially in coastal marine areas.
Iodites continuously leave the body, and their replenishment occurs continuously due to both externally (food, water, inhaled air) and internally (thyroid and salivary glands, gastric juice and absorption of the breakdown products of thyroid hormones). These processes that constantly occur in the body maintain a normal level of iodine. The exchange of iodine in the thyroid gland and its relationship with thyroid hormones is one of the most important moments of the body's work.
The concentration of iodine in the local drinking water reflects the concentration of iodine in the soil. Usually, in iodinedeficient regions, the concentration of iodine in water is less than 2 µg/l. Water, as a rule, is not a serious source of iodine intake in the human body. Since drinking water contains little iodine, we consume the main amount of this micro component with food. The highest concentration of iodine is present in seafood (Table 1).