191
Did you know that iodine is the heaviest element our body needs, yet one of the few we cannot ingest for preventive purposes? Nature provides natural sources of iodine in optimal amounts and concentrations for the body, but in the pharmacy, you will find only iodine compounds, solutions, ointments, and dietary supplements. When and how the antiseptic is applied and why it is not advisable to purchase it without medical consultation will be explained in the following lines.
Iodine is a chemical element from the group of stable halogens (along with fluorine, chlorine, and bromine) and is a gray-black crystalline substance with a metallic sheen. It has the property of melting at 114°C but starts boiling only at 183°C, forming a violet gas, which is where its name comes from. It originates from the Greek word for "violet," and the element was named by the French chemist and physicist Louis Joseph Gay-Lussac in 1813.
Iodine and Chemistry
By nature, iodine is a strong oxidizer and is often used as a catalyst for various chemical reactions. It is poorly soluble in water, so different alcohols and amines are used to lower its concentration. The result is the familiar liquid solution with a rich brown color, used for disinfection during injuries and surgical operations.
Today, iodine is mainly used in medicine, the food industry, and analytical chemistry, such as:
- Catalyst in the production of acetic acid and certain polymers
- Key element for detecting the presence of ammonia, ammonium ions, and starch
- Non-toxic contrast agent in radiology
- Component in photographic developers
- Active ingredient in stabilizers, paints, dyes, pigments, pharmaceuticals, and sanitary products
- In addition, iodine is often used to combat smog and hail and to induce rainfall. It is still used to detect counterfeit banknotes printed on paper containing starch (cellulose).
Iodine in Nature
Iodine is an important element in nature, found in small amounts in water, air, soil, and almost all living organisms, from plants to mammals. Unfortunately, the body cannot produce this element on its own, so it is important to obtain it through food, water, and air.
The largest natural source of iodine is the seas, oceans, and their inhabitants. Fish, clams, seaweed, and other aquatic animals form iodine in their bodies. Since its salts are easily soluble in water, saline water bodies are also saturated with iodine compounds.
On land, iodine penetrates the soil through groundwater, so its concentration in fruits, vegetables, and animal products (meat, milk, eggs, etc.) directly depends on the region where they grow. Foods grown near seas and oceans are usually rich in iodine, unlike those from mountains and large plains.
Iodine can also be absorbed through the air by inhaling natural iodine vapors characteristic of coastal areas.
In food, iodine is rarely found in its pure form and is mainly present as salts – sodium and potassium salts, inorganic iodine, iodate, and iodide. The easiest and most popular way to meet daily iodine needs is by using iodized salt.
Iodine in Medicine
The element is truly valuable due to its strong antibacterial action, even in small concentrations. Its specific mechanism of action is unknown, but it is believed to damage vital cellular elements of viruses and bacteria, quickly killing them by causing cell breakdown. This is why iodine solutions are widely used in surgery for disinfection before and after operations and surgical procedures.
In human medicine, iodine is included in various preparations for treating wounds or skin damage, but never in its pure form. Saline and alcohol solutions (e.g., potassium iodide, povidone-iodine, etc.) are used, with concentrations not exceeding 5-10% per 100 ml. This equates to only 5-10 milligrams of solution, where pure iodine is in very low concentration. Even so, it should not be overused, as prolonged use can damage tissues, especially mucous membranes.
Usually, iodine solutions are incorporated into creams, ointments, and balms, while the popular brown liquid is for disinfecting superficial wounds. All products are intended for external use and should never be ingested, as they can cause esophageal burns. Ingestion can also lead to other unpleasant side effects, such as diarrhea, nausea, vomiting, skin redness, and even heart palpitations.
In the pharmacy network, dietary supplements in the form of tablets and drops can be found, but they do not have therapeutic properties. They contain a combination of ionic salts and minerals similar to ordinary iodized salt, aiming to maintain iodine balance in the body.
Iodine and the Thyroid Gland
No living organism, including humans, can develop properly without iodine. This is because the element supports the synthesis of the most important hormones in the body – thyroxine and triiodothyronine, known as "growth hormones," produced by the thyroid gland. Therefore, the thyroid gland is directly dependent on iodine levels in the body.
If the body has sufficient iodine, the thyroid gland produces enough growth hormones. However, iodine deficiency can lead to a condition known as goiter or hypothyroidism. The thyroid gland is located near the throat, and its enlargement leads to a swollen neck – a typical symptom of iodine deficiency.
More serious problems arise when impaired thyroid function affects the entire body. The lack of thyroid hormone affects heart, brain, and muscle functions and is particularly dangerous during pregnancy and breastfeeding. It can cause developmental delays in the fetus and neurological damage in the child. Iodine deficiency is considered responsible for many brain impairments worldwide.
Symptoms of iodine deficiency include:
- Enlarged thyroid gland (goiter)
- Weight gain resistant to diet and exercise
- Fatigue and weakness
- Dry, flaky skin
- Hair loss
- Increased sensitivity to cold
- In rarer cases, memory and heart rate changes occur. In women, the menstrual cycle may change or disappear entirely.
Iodine and Radiation
Of the 37 known isotopes of iodine, only one occurs naturally – iodine-127 (127I). The others are radioactive, mainly produced synthetically, and decay relatively quickly (within hours or days), emitting gamma rays and other particles. However, they are not always harmful. For example, iodine-123 is used for diagnostics in CT scans, and iodine-125 is used in radiation therapy for cancer treatment, including brain tumors. Other isotopes are used in radiopharmaceuticals as contrast agents or active ingredients in infusion solutions.
A harmful isotope is iodine-131, formed due to radioactive contamination. It accumulates in the body, causing severe thyroid damage and even cancer.
The thyroid gland cannot distinguish between iodine isotopes and retains all ingested iodine for a long period. To prevent this during X-ray imaging, the body, especially the throat, is covered with a special lead apron that absorbs radiation. In the case of radioactive contamination of air, water, or food, the only protection is consuming large amounts of stable iodine-127 within 10 to 24 hours before exposure. This saturates the thyroid gland with non-radioactive iodine, blocking the absorption of radioactive iodine-131.
Iodine tablets are prescribed only by authorized personnel. In Bulgaria, potassium iodide tablets are provided by the Ministry of the Interior during radiation emergencies.
