The Thyroid and Iodine Connection

June 27, 2024

The Thyroid is a small butterfly-shaped organ located at the base of your neck which plays a pivotal role in regulating various physiological processes. Despite its modest size, the thyroid influences almost every cell, tissue, and organ in the body. It produces two primary hormones, thyroxine (T4) and triiodothyronine (T3), which are critical for controlling the body's metabolism, heart function, digestive health, muscle control, and brain development. The thyroid gland also secretes calcitonin, a hormone that aids bone cells in processing calcium and incorporating it into the bone matrix.

Thyroid hormones are fundamental to the body's energy regulation. They determine how quickly cells convert nutrients into energy, thus impacting everything from body temperature to heart rate. An imbalance in these hormones can lead to significant health issues.

Iodine and its Role in the Body

Iodine is a trace element that is indispensable for thyroid health. It is a crucial building block for the synthesis of thyroid hormones. Without adequate iodine, the thyroid cannot produce sufficient T3 and T4 hormones, leading to disrupted metabolic processes and a variety of health problems. 

Dietary iodine is absorbed in the small intestine and transported to the thyroid gland, where it is used to produce thyroid hormones. Iodine deficiency remains a global public health concern. According to functional nutritionist Mugdha Pradhan, iodine deficiency affects one-third of the global population. 

Rich dietary sources of iodine include seafood, seaweed, dairy products, eggs and iodized salt. However, dietary habits and regional differences can significantly influence iodine intake.

The Thyroid-Iodine Connection

The relationship between iodine and thyroid function is complex and crucial. The thyroid gland relies on iodine to synthesize the hormones T3 and T4. These hormones are essential for regulating metabolism and maintaining energy levels. 

Iodine Deficiency and Thyroid Disorders

When the body lacks adequate iodine, the thyroid gland struggles to produce sufficient hormones. This deficiency can lead to hypothyroidism. Hypothyroidism is characterized by symptoms such as fatigue, weight gain, and depression. A lack of iodine can also cause the thyroid gland to enlarge, resulting in a condition known as goiter. Severe iodine deficiency during pregnancy can lead to cretinism, a condition marked by severe mental and physical developmental delays in infants.

According to the World Health Organization (WHO), iodine deficiency is the leading cause of preventable intellectual and developmental disabilities worldwide. It highlights the critical role iodine plays in growth and cognitive function, particularly in developing countries where iodine deficiency is more prevalent.

Iodine Excess and Thyroid Health

While iodine is essential, too much of it can also be problematic. Excessive iodine intake can lead to hyperthyroidism, a condition where the thyroid produces too much hormone, resulting in symptoms like rapid heartbeat, weight loss, and nervousness. Additionally, high iodine levels can trigger autoimmune thyroid diseases such as Hashimoto's thyroiditis and Graves' disease.

The delicate balance of iodine intake underscores the importance of personalized nutrition and careful monitoring, as both deficiency and excess can disrupt thyroid function and overall health.

Assessing Iodine Status

Functional nutritionists use various methods to assess iodine levels in individuals. Urinary iodine concentration is commonly measured as it reflects recent iodine intake. Blood tests can also provide insights into thyroid function and hormone levels. These assessments help determine whether a person’s iodine levels are adequate, deficient, or excessive, guiding personalized dietary and supplementation strategies.

Functional nutrition focuses on identifying and addressing the root causes of thyroid imbalances. By understanding a person's unique biochemical needs and lifestyle factors, nutritionists can develop tailored plans that optimize iodine intake and support overall thyroid function.

Recommended Iodine Intake

Achieving the right balance of iodine is critical for thyroid health. The recommended daily intake of iodine varies across different population groups. For adults, the general guideline is 150 micrograms per day, while pregnant and breastfeeding women require higher amounts to support fetal and infant development. It's important to note that when people consume enough iodine in their diet, the thyroid gland retains less than 10% of the iodine absorbed from the gut. However, in cases of long-term iodine deficiency, the thyroid gland can capture over 80% of the iodine from the blood.

Functional nutritionists advocate for a diet rich in natural sources of iodine, such as sea vegetables (e.g., kelp), fish, and dairy products. They also emphasize the importance of avoiding excessive iodine intake, particularly from supplements and fortified foods, to prevent thyroid dysfunction. 

Iodine Supplementation

Iodine supplementation can be beneficial for individuals who are unable to meet their iodine needs through diet alone. However, the form and dosage of iodine supplements, such as potassium iodide or iodine drops, should be approached with caution and carefully selected based on individual needs.

To counter iodine deficiency, governments of many countries have approved the manufacturing of table salts iodized by potassium iodide and cuprous iodine. However, it is recommended by many functional nutritionists to use Himalayan pink salt (sindhav namak) as it has more than 60 trace minerals, including iodine, and its consumption does give no risk of over intake.

Risks and Considerations

Excessive iodine supplementation can disrupt thyroid function and lead to adverse effects. Functional nutritionists stress the importance of monitoring iodine levels and adjusting supplementation as needed. They also consider introducing other nutrients that interact with iodine, such as selenium and B vitamins, which is essential for thyroid hormone metabolism and antioxidant protection.

The thyroid-iodine connection is a cornerstone of thyroid health, highlighting the importance of balanced iodine intake for optimal hormone production and metabolic function. Functional nutrition provides a comprehensive approach to managing this delicate balance, ensuring that individual needs are met through personalized dietary and lifestyle strategies.

By understanding the critical role of iodine and adopting integrative approaches to thyroid health, individuals can support their thyroid function and overall well-being effectively. Through careful assessment, balanced nutrition, and lifestyle adjustments, the complexities of thyroid health can be managed, promoting long-term health and vitality.


  1. Dilas, L. T., Bajkin, I., Icin, T., Paro, J. N., & Zavisić, B. K. (2012). Medicinski pregled, 65(11-12), 489–495. 
  2. Pradhan, M., & Dave, S. (2023, December 19). Thyroid dysfunction- what to eat and what not to eat. Food and Nutrients | iTHRIVE. 
  3. Thyroid problems: symptoms, causes, natural treatment - Dr. Axe. (2023, October 16). Dr. Axe. 
  4. Eastman, C. J., & Zimmermann, M. B. (2018, February 6). The iodine deficiency disorders. Endotext - NCBI Bookshelf. 
  5. Hypothyroidism. (n.d.-b). Mount Sinai Health System.,problems%20in%20the%20pituitary%20gland
  6. MS, C. K. (2022a, September 22). Iodine for hypothyroidism: Crucial nutrient or harmful toxin? Chris Kresser. 
  7. Sorrenti, Salvatore & Baldini, Enke & Pironi, Daniele & Lauro, Augusto & D'Orazi, Valerio & Tartaglia, Francesco & Domenico, Tripodi & Lori, Eleonora & Gagliardi, Federica & Praticò, Marianna & Illuminati, Giulio & D'Andrea, Vito & Palumbo, Piergaspare & Ulisse, Salvatore. (2021). Iodine: Its Role in Thyroid Hormone Biosynthesis and Beyond. Nutrients. 13. 4469. 10.3390/nu13124469.  
  8. Iodine deficiency Symptoms, risk factors and treatment - Dr. Axe. (2024, May 16). Dr. Axe. 
  9. Sugandhi, R., & Dave, S. (2023, December 19). Selenium: the underrated micro nutrient you need in your diet. Food and Nutrients | iTHRIVE. 

Sharvi Dave
Research Associate

Experienced writer with a demonstrated history of working in the writing & editing history. skilled in writing, communication, digital marketing, & general aviation. Strong media & communication professional with a Bachelor of Science - Bs focussed in Aeronautics/Aviation/Aerospace Science & Technology General from Bombay Flying Club.

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.