Iodine, also known as iodine , is an essential trace element that plays a crucial role in the production of thyroid hormones. These hormones regulate the body's metabolism, growth, and development. Since the body cannot produce iodine on its own, it must be obtained through food or supplements. In this article, you'll learn all about iodine, its health benefits, how it works in the body, and how to use it safely.
What is iodine?
Iodine is a trace element primarily required for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) . These hormones control a variety of processes in the body, including energy metabolism, heart rate, and growth. Since iodine is present only in small amounts in soil and water, it is added to many foods, especially table salt, to meet the population's iodine needs [1].
Synonyms for iodine
Iodine is also referred to as iodine or in combination with other compounds, such as potassium iodide or sodium iodide . In dietary supplements, iodine is often listed as potassium iodide or iodide [2].
Where does iodine come from?
Iodine occurs naturally in seafood, fish, and algae. These foods are particularly rich in iodine because it is found in seawater. In many countries, iodine is also added to table salt to prevent deficiency. This is especially important in areas where soil iodine levels are low, such as many regions in Europe and Asia [3].
How is iodine produced?
Iodine is obtained by extracting iodine-containing compounds from natural sources such as seawater, algae, or certain minerals. Industrially, iodine is often used in the form of potassium iodide or sodium iodide in dietary supplements or iodized table salt to meet daily needs [4].
Health benefits of iodine
Iodine and thyroid function
The most important health benefit of iodine is its role in the production of thyroid hormones. The thyroid gland needs iodine to synthesize the hormones thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, body temperature, and energy balance. A deficiency in iodine can lead to an underactive thyroid ( hypothyroidism ), characterized by symptoms such as fatigue, weight gain, and sensitivity to cold [5].
Iodine and mental development
Iodine is particularly important for brain development in fetuses and young children. Iodine deficiency during pregnancy can lead to mental retardation and a lower intelligence quotient (IQ) in the child. For this reason, pregnant women are strongly advised to ensure adequate iodine intake to support the healthy development of their child's brain and nervous system [6].
Iodine and energy metabolism
Since thyroid hormones regulate energy metabolism, iodine indirectly contributes to maintaining a healthy metabolism. Adequate iodine intake ensures that the thyroid produces enough hormones to help the body convert nutrients into energy. People with iodine deficiency often experience fatigue, weight gain, and a slow metabolism [7].
Iodine and immune function
Iodine may also support immune function, as thyroid hormones are involved in regulating the immune response. Adequate iodine intake may help strengthen the immune system and better protect the body against infections. There is evidence that iodine has antibacterial and antiviral properties that contribute to overall health [8].
If you are looking for another way to support your immune system, this article might be of interest to you: Elderberry – Strengthen your immune system & prevent colds .
Iodine and goiter formation
A persistent iodine deficiency can lead to an enlargement of the thyroid gland, known as goiter . This occurs because the thyroid tries to produce more hormones to compensate for the lack of iodine. By increasing iodine intake, either through food or supplements, goiter can be reduced or prevented [9].
How does iodine work in the body?
Iodine is absorbed by the thyroid gland and incorporated into the hormones thyroxine (T4) and triiodothyronine (T3). These hormones regulate metabolism, body temperature, and the function of many organs. Iodine is also important for the normal development of the brain and nervous system, especially during pregnancy and childhood. It acts by regulating thyroid hormones, thus contributing to the maintenance of energy production and cellular function [10].
Recommended dosage and use of iodine
What is the recommended dosage?
The recommended daily intake (RDA) of iodine is approximately 150 micrograms per day for adults. Pregnant and breastfeeding women have an increased need of 220 to 290 micrograms per day to support the healthy development of the fetus and child. In regions where dietary iodine content is low, the use of iodized table salt or dietary supplements is recommended [11].
When should you take iodine?
Iodine can be taken at any time of day, preferably with food to enhance absorption. Iodine is typically obtained through iodized salt or supplements when natural dietary intake is inadequate. Pregnant and breastfeeding women are advised to monitor their iodine intake to ensure their needs are met [12].
Side effects and safety of iodine
Is iodine safe?
Iodine is safe and well-tolerated in recommended amounts. However, excessive intake can lead to side effects such as hyperthyroidism or worsening of thyroid disorders. Long-term iodine overdoses, especially in people with pre-existing thyroid problems, can lead to health complications. It is recommended to keep daily iodine intake in the range of 150 to 290 micrograms unless a doctor recommends higher doses [13].
What are the side effects of iodine?
Rare side effects of excessive iodine intake include symptoms such as iodine acne, skin rashes, gastrointestinal disturbances, and thyroid dysfunction. People with thyroid problems, such as Hashimoto's thyroiditis or Graves' disease , should carefully monitor their iodine intake, as too much iodine can worsen their conditions. It is recommended to adhere to the recommended dosages and consult a physician if unsure [14].
Iodine compared to other trace elements
Iodine vs. Selenium
Iodine and selenium work closely together to support thyroid function. While iodine is responsible for the production of thyroid hormones, selenium is important for activating these hormones and protecting the thyroid from oxidative stress. Both trace elements are essential for thyroid health and should be consumed in sufficient quantities through the diet [15].
Iodine vs. Zinc
Zinc is another essential trace element important for the immune system and cell division. While iodine primarily regulates thyroid function, zinc supports immune function and hormone balance. Both minerals are necessary for overall health and complement each other, particularly in supporting metabolism and immune function [16].
Natural sources of iodine
Iodine is found in high amounts in seafood such as fish, shrimp, mussels, and algae. Dairy products, eggs, and iodized table salt are also good sources. People living in regions where soil iodine levels are low should rely on iodized foods or supplements to meet their needs. Seaweed and other algae products are particularly rich in iodine and a popular source for vegans [17].
Iodine in food supplements
Iodine is often offered in dietary supplements in the form of potassium iodide or sodium iodide. These forms are readily bioavailable and well-suited to supplement daily iodine intake. Iodine supplements are often recommended for people living in areas with iodine-poor soil or following a vegan diet, as plant-based foods are typically low in iodine [18].
Final thoughts on iodine
Iodine is an essential trace element crucial for the production of thyroid hormones and the regulation of metabolism. It plays an important role in mental development, energy production, and overall health. For people living in regions with low iodine levels in the soil or following a plant-based diet, it is important to ensure iodine intake through supplements or fortified foods.