Iodine, also known as iodine , is an essential trace mineral 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 that is mainly 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 body growth. Since iodine is only found in small amounts in soil and water, it is added to many foods, especially table salt, to meet the iodine needs of the population [1].

Iodine is also referred to as iodide 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].

Iodine occurs naturally in seafood, fish and seaweed. 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].

Iodine is obtained by extracting iodine-containing compounds from natural sources such as seawater, algae or certain minerals. In industry, iodine is often used in the form of potassium iodide or sodium iodide in food supplements or iodized table salt to meet daily needs [4].

Health Benefits of Iodine

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 is particularly important for brain development in fetuses and young children. Iodine deficiency during pregnancy can lead to mental development disorders and a lower intelligence quotient (IQ) in the child. For this reason, pregnant women are strongly advised to ensure they have adequate iodine intake to support the healthy development of their child's brain and nervous system [6].

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 an iodine deficiency often tend to experience fatigue, weight gain, and a slow metabolism [7].

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].

A persistent iodine deficiency can lead to an enlargement of the thyroid gland, known as a goiter . This happens because the thyroid tries to produce more hormones to compensate for the lack of iodine. By increasing iodine intake, either through diet or supplements, goiter can be reduced or prevented [9].

How does iodine work in the body?

Iodine is taken up 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 works by controlling thyroid hormones, helping to maintain energy production and cellular function [10].

Recommended dosage and use of iodine

The recommended daily allowance (RDA) of iodine is about 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 the iodine content of the diet is low, the use of iodized table salt or dietary supplements is recommended [11].

Iodine can be taken at any time of the day, preferably with a meal to improve absorption. Typically, iodine is 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 that needs are met [12].

Side effects and safety of iodine

Iodine is safe and well tolerated in recommended amounts, but excessive intake may cause side effects such as overactive thyroid ( hyperthyroidism ) or worsening of thyroid conditions. Long-term overdoses of iodine, 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].

Rare side effects of excessive iodine intake include symptoms such as iodine acne, skin rashes, gastrointestinal complaints 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 stick to the recommended dosages and consult a doctor if in doubt [14].

Iodine compared to other trace elements

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 diet [15].

Zinc is another essential trace element that is important for the immune system and cell division. While iodine mainly regulates thyroid function, zinc supports immune function and hormone balance. Both minerals are necessary for general health and complement each other in their effects, especially 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 seaweed. Dairy products, eggs and iodized table salt are also good sources. People living in regions where the iodine content of the soil is low should rely on iodized foods or supplements to meet their needs. Seaweed and other seaweed products are particularly rich in iodine and are a popular source for vegans [17].

Iodine in dietary supplements

Iodine is often offered in dietary supplements in the form of potassium iodide or sodium iodide. These forms are easily 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 usually low in iodine [18].

Final Thoughts on Iodine

Iodine is an essential trace element that is crucial for the production of thyroid hormones and the regulation of metabolism. It plays an important role in mental development, energy production and general health. For people living in regions with low iodine levels in the soil or who follow a plant-based diet, it is important to ensure iodine intake through supplements or fortified foods.

references

[1] Examine.com. Jodine. Available at: https://examine.com/supplements/iodine/
[2] WebMD. Jodine - Uses and Benefits. Available at: https://www.webmd.com/vitamins/ai/ingredientmono-35/iodine
[3] Healthline. Jodine: Benefits, Uses, and Side Effects. Available at: https://www.healthline.com/nutrition/iodine
[4] Examine.com. Iodine Sources and Supplements. Available at: https://examine.com/supplements/iodine/
[5] Mayo Clinic. Iodine for Thyroid Health. Available at: https://www.mayoclinic.org/drugs-supplements-iodine/art-20364618
[6] National Institutes of Health. Iodine and Brain Development. Available at: https://ods.od.nih.gov/factsheets/Jodine-HealthProfessional/
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[8] Healthline. Iodine and immune function. Available at: https://www.healthline.com/nutrition/iodine-benefits
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[10] Examine.com. Jodine in the Body. Available at: https://examine.com/supplements/iodine/
[11] WebMD. Iodine Dosage and Usage. Available at: https://www.webmd.com/vitamins/ai/ingredientmono-35/iodine
[12] Healthline. Iodine Supplements: Dosage and Timing. Available at: https://www.healthline.com/nutrition/iodine-supplements
[13] Mayo Clinic. Iodine Safety and Side Effects. Available at: https://www.mayoclinic.org/drugs-supplements-iodine/art-20364618
[14] WebMD. Jodine Side Effects. Available at: https://www.webmd.com/vitamins/ai/ingredientmono-35/iodine
[15] Examine.com. Iodine vs. Selenium. Available at: https://examine.com/supplements/selenium/
[16] Examine.com. Iodine vs. Zinc. Available at: https://examine.com/supplements/zinc/
[17] National Institutes of Health. Natural Sources of Iodine. Available at: https://ods.od.nih.gov/factsheets/Jodine-HealthProfessional/
[18] Healthline. Iodine Supplements Benefits. Available at: https://www.healthline.com/nutrition/iodine-supplements