The Betterment Project

What Is Nascent Iodine & What's Its Role In Thyroid Health?

In the early 20th century many within the U.S. were deemed iodine deficient. To combat the prevalence of iodine deficiency researchers and scientists figured out a way to fortify dietary iodine. 


The concern led to the creation of a common dinner table item — table salt. 


This iodized salt first became available in the U.S. in the 1920s. However, over the years iodine fortified foods such as table salt has fallen out of favor due to the growing concerns over sodium consumption. 


This decline has caused many to raise concerns of potential iodine deficiency in the general population. It is of special concern because of iodine’s vital role in thyroid health.


But what is iodine? What about its supplemental forms, such as nascent iodine? 

Why is it so important to thyroid health? Let’s explore these questions a bit further. 

What is Iodine?

Iodine is an essential trace mineral and it has a critical part to play in many of our body’s systems. This micronutrient has a most crucial role in the thyroid health; specially, thyroid hormone production. 

Why is Iodine Important?


The health benefits for iodine are numerous. So, we will look at just a few, but we will focus more heavily on its role in thyroid health. 


Fetal and Infant Development

Iodine for fetal development cannot be overstated. During development, the fetus relies heavily on maternal hormones, especially thyroxine (T4). 


This is pivotal for proper fetal thyroid development. This hormonal demand increases during pregnancy so iodine intake is crucial. 


Cognitive Function and Immunity


Related to fetal development, iodine deficiency is linked to intellectual disability as it has a critical role in brain development. 


Iodine may help keep the brain sharp too. 


One research study found that iodine supplementation (150 mcg/day) had a role to play in the improvement of overall cognitive function and perceptual reasoning in iodine deficient children. 


Iodine and Immunity


Iodine also has a part to play in supporting the immune system, mainly because of its role in thyroid hormone regulation. Through this process, it helps support the immune response activity of immunity cells. 

Iodine and Thyroid Health

The most important function for iodine in the body is for thyroid health. The thyroid is a small butterfly-shaped gland that forms three sides around your windpipe at the base of your neck. 


Hormone Function


Its primary job is in the production of two very important hormones: Thyroxine (T4) and triiodothyronine (T3). These two hormones help produce and regulate other hormones; mainly, adrenaline and dopamine. 

Adrenaline and dopamine are vital for physical and emotional response and have an important part to play in metabolism.


Hormones are vital as chemical messengers as they signal other organs and tissue to carry out their functions. They are secreted directly into the bloodstream and carried throughout the body. 


They regulate numerous body systems and processes: Development and growth, sexual function, metabolism, and cognitive function.


Iodine Promotes Thyroid Function and Overall Health


The hormones secreted by the thyroid gland rely on iodine to form and carry out their proper functions. 

Iodine is used in small amounts within the thyroid gland. Simply put, without iodine the hormone production would decrease and become underactive. This can lead to fatigue, weight gain, and even decreased mental health. 


Furthermore, iodine, in some forms (radioiodine), has been used to treat overactive thyroid glands – hyperthyroidism.

Sources of Iodine

Iodine is consumed in three ways: Naturally present in many foods, fortified (in salts), and as a dietary supplement. 

Recommended Dietary Allowance (RDA)


The recommended dietary allowance for iodine varies depending on age. For adults, the amounts are 150 mcg. Special recommendations are made for those who are pregnant or lactating: Pregnant; 220 micrograms and lactating: 290 micrograms


Iodine in food


Iodine is contained in the earth’s soil and available in varying amounts in many crops. These iron-enriched crops are not equally available around the world. 

The bioavailability of iodine through food is low in areas which have iron-deficient soils. 


Surprisingly, seaweed is among one of the top natural food sources for dietary iodine; 10 g boasts 232 mcg of iodine per serving — that is 155 % of its daily value. 

Other iodine-rich foods include:


  • Cod – 3 ounces; 185 mcg 


  • Greek yogurt – 1 cup; 116 mcg


  • Oysters – 3 ounces; 93 mcg 


  • Milk, nonfat – 1 cup; 85 mcg


Iodine in Fortified Foods and Salts


As stated above, the risk of iodine deficiency led to the development of fortified iodine and iodization programs. 


The most common form is iodized table salt, which has approximately 76 mcg of iodine per serving (1/4 teaspoon). 


Fortified iodine foods like breads and pasta made with iodate-enriched dough conditioners can yield around 36 – 198 per serving. 

Those more susceptible for iodine deficiency are those who live in countries with iodine-deficient soils, those who are pregnant, and sometimes those who follow vegetarian and vegan diets as many plant sources have generally lower levels of iodine. 


Supplemental Iodine


As a dietary supplement, iodine is usually found in the form of potassium iodide. Many multivitamin supplements, such as Superhuman Supplements, contain this type of iodine. 

Studies have shown that iodine in potassium iodide is able to be absorbed at a rate of 96.4 %, which makes for a very high bioavailability. 

Furthermore, iodine drops, such as nascent iodine, are also a popular form of dietary iodine. 

What is Nascent Iodine

Nascent iodine is a popular supplemental form of iodine. What sets it apart from other forms of iodine is its atomic nature; thus, it is sometimes referred to as atomic iodine. 


This simply means it is able to hold its atomic structure, making it safe for both consumption and topical use. It also makes for a higher bioavailability within the body as it comes ready in iodide form, rather than having to be converted during the digestive process. 


What Does Nascent Iodine Do?

In short, nascent iodine helps keep iodine levels within the body at optimal range, especially when dietary means are ineffective or iodine deficiencies are present. 


Nascent Iodine’s Role in Thyroid Health

Since nascent iodine is more easily absorbed and utilized in the body due to its higher bioavailability, it makes it easier for the thyroid gland to maintain its homeostasis and function. 


It aids in the process that is already being carried out by simply making iodine better available to be used within the thyroid hormone production process — producing T4 and T4. 

The Bottom Line on Iodine

Iodine is an important trace mineral within the body. Its availability is vital for the proper function of the hormonal regulatory process within the thyroid gland. 


However, low dietary consumption of iodine is always a concern, especially in regions where iodine-enriched soil is scarce. For this reason, many fortified forms of iodine have found their way into many foods; e.g. iodized salt. 

Don’t Discount Supplemental Forms of Minerals

However, there are supplemental forms of iodine as well – potassium iodide and nascent iodine being the most prevalent. Nascent iodine helps the regulatory process of the thyroid by keeping availability of iodine within the body at optimal levels. 


Getting all the proper amounts of vitamin, minerals, and nutrients from your food alone is ideal, but not usually possible. 

Nutritional supplements, especially among commonly low-deficiency minerals like iodine, are always an option to help get your levels where they need to be. 


History of US Iodine Fortification and Supplementation | NCBI

Iodine supplementation improves cognition in mildly iodine-deficient children | NCBI

Bioavailability of seaweed iodine in human beings | NCBI

Mechanisms of thyroid hormone action | NIH

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This article has been reviewed by members of our Scientific Advisory Board.

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