Iodine and Its Essential Role in Human Health
Iodine is a vital halogen element that plays an important role in human health, industry, and technology. Represented by the symbol I and atomic number 53, iodine belongs to Group 17 of the periodic table, alongside chlorine, fluorine, and bromine. Unlike its gaseous halogen relatives, iodine is a lustrous, blue-black solid at room temperature and sublimates into a violet-colored vapor when heated. Despite being relatively rare in the Earth’s crust, iodine is an essential micronutrient for humans and animals, primarily known for its role in thyroid function. Beyond its biological importance, iodine has wide applications in medical treatments, pharmaceuticals, nutrition, agriculture, and various industrial processes, making it a highly valuable element.
The biological significance of iodine lies primarily in the synthesis of thyroid hormones. The thyroid gland uses iodine to produce thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, growth, and development. A deficiency in iodine can lead to goiter, hypothyroidism, and developmental disorders, particularly in children. For this reason, many countries have implemented iodine fortification programs, most commonly by adding iodine to table salt, known as iodized salt. This public health initiative has significantly reduced iodine deficiency disorders worldwide. On the other hand, excessive iodine intake can also cause thyroid dysfunction, highlighting the need for a balanced intake.
Natural sources of iodine include seawater, seaweed, fish, dairy products, and some plants grown in iodine-rich soil. Marine sources, especially seaweed, are among the richest sources, which explains why coastal populations historically experienced fewer iodine-related health issues compared to inland regions. Soil depletion in certain areas leads to low iodine levels in crops, contributing to regional variations in dietary iodine intake. This geographic disparity is one of the main reasons why iodine supplementation remains an essential global health measure.
In medicine, iodine plays a crucial role beyond nutrition. It is widely used as an antiseptic and disinfectant. Iodine solutions, such as povidone-iodine, are commonly applied to wounds, surgical sites, and skin preparation before operations to prevent infections. Its antimicrobial properties make it effective against bacteria, viruses, and fungi, making it a trusted tool in hospitals and clinical environments. In addition, iodine-containing compounds are utilized in radiology and diagnostic imaging. For instance, halogen, thyroid health, disinfectant, iodine-based contrast agents are injected into patients undergoing X-rays or CT scans to improve visualization of blood vessels and internal organs, thereby assisting in accurate diagnosis.
Pharmaceuticals also rely on iodine derivatives for a variety of applications. Compounds like iodoform and certain iodine salts are used in medical formulations. Iodine is also employed in the production of antiseptic solutions, expectorants, and nutritional supplements. Its significance in pharmaceuticals underscores its indispensable role in both preventive and therapeutic healthcare practices. Fortunately, iodine has relatively low toxicity compared to other halogens, but improper disposal can still pose ecological risks. Recycling and recovery processes are being developed to maximize efficiency and reduce environmental impact, particularly in industries such as electronics where iodine-based materials are used extensively.