What is Iodine and What is its Use?
Iodine is essential for a wide range of health, from thyroid function to metabolism, from nervous system development to energy levels. Since iodine deficiency can lead to a number of health problems, it is important to consume iodine-containing foods regularly. Scientific research reveals in detail the benefits of iodine and the negative effects that its deficiency can create. In this content, we have examined the answers to questions such as what is iodine, why is it important for the body, and which foods contain iodine.
What is Iodine?
Iodine is a vital mineral for the human body. It is especially necessary for the proper functioning of the thyroid gland. Iodine is present in the structure of the hormones produced by the thyroid gland (triiodothyronine – T3 and thyroxine – T4), and these hormones play a critical role in regulating metabolism. The iodine element cannot be naturally synthesized by the body; it must be obtained through food or supplements.
In case of iodine deficiency, the normal functioning of the thyroid gland may be disrupted and various health problems may occur. According to the findings of the World Health Organization WHO ; iodine deficiency can cause serious effects on brain development, especially during pregnancy and childhood.
Study: Lodine status worldwide
Findings: This report analyses the iodine status worldwide, examining in detail the health effects of iodine deficiency. Defines what iodine is.
Source: World Health Organization (WHO)
Daily Iodine Need
Daily iodine requirements vary by age, gender, and special circumstances (e.g. pregnancy). The World Health Organization (WHO), American Thyroid Association (ATA), and other health organizations recommend the following daily iodine intakes:
| Age group | Daily Iodine Requirement (mcg) |
| 0-6 months | 110 |
| 7-12 months | 130 |
| 1-8 years old | 90 |
| 9-13 years old | 120 |
| Ages 14 and up | 150 |
| Pregnant women | 220 |
| Breastfeeding women | 250 |
World Health Organization (WHO)
When determining the daily iodine requirement, WHO emphasizes the importance of iodine in the production of thyroid hormones and states that these hormones play vital roles in metabolism, growth and development . WHO’s 2007 report “Assessment of Iodine Deficiency Disorders and Monitoring their Elimination” provides detailed information on this subject.
Source: WHO – Assessment of Iodine Deficiency Disorders
Institute of Medicine (IOM)
The “Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc” report published by the IOM in 2001 includes detailed iodine requirement values according to age and gender.
Source: Institute of Medicine
American Thyroid Association (ATA)
The ATA emphasizes the importance of increased iodine requirements, especially for pregnant and lactating women, focusing on the effects of iodine on brain development during pregnancy and lactation.
Source: American Thyroid Association – Iodine Deficiency
What are the symptoms of Iodine Deficiency?
Potential increases in iodine-related thyroid diseases have increased the importance of iodine deficiency symptoms. Symptoms of iodine deficiency in the body and conditions that may occur due to iodine deficiency can be listed as follows:
- Goiter (enlargement of the thyroid gland)
- Hypothyroidism (Symptoms such as fatigue, weight gain, cold intolerance, depression and poor memory)
- Mental retardation in pregnancy and children (Iodine deficiency in pregnant women can cause low IQ, growth retardation and mental retardation)
- Developmental delay (slowing down of physical and mental development in children)
- Dry skin and hair loss (Skin and hair problems caused by insufficient thyroid hormones)
- Visible swelling of the neck
- Slowing down of metabolism
- Getting fat
- Low energy
- Cold intolerance
- Thickening of the skin
According to the findings of the World Health Organization WHO, iodine deficiency is an important risk factor, especially for pregnant women, babies and children. When the benefits and risks of iodine prophylaxis during pregnancy are examined, iodine deficiency can lead to serious problems such as poor pregnancy outcomes, cretinism and irreversible mental retardation.
Study: Iodine deficiency in Europe: a continuing public health problem
Findings: This report provides a detailed overview of the prevalence of iodine deficiency in Europe and its health impacts. It shows the symptoms of iodine deficiency.
Source: World Health Organization (WHO)
Ensuring optimal iodine intake in the range of 150-250 µg/day for adults helps prevent symptoms of iodine deficiency in the body and minimize the amount of thyroid dysfunction.
According to World Health Organization estimates, health policy makers should subscribe to the same reference daily intake (RDI) for this element in order to prevent iodine deficiency disorders, which affect 30% of the world’s population.
Study: Zimmermann, MB (2009). Iodine deficiency
Findings: This study discusses iodine deficiency in detail.
Source: Endocrine reviews, 30(4), 376-408
You can test your urine for iodine deficiency at home by using an iodine test kit to determine the iodine concentration in your urine. Iodine test kits are available from pharmacies or online health stores.
What are the benefits of iodine?
In addition to being an essential element in thyroid hormones, iodine has many biological functions. Iodine benefits can be listed as follows:
- High amounts of iodine intake may increase immune function.
- It plays a key role in the synthesis of thyroid hormones.
- It may reduce the incidence (chance of getting the disease) of breast cancer.
- It is effective in the development of cells.
- It is beneficial for the fetus during pregnancy.
- It alleviates the effects of infection.
Strengthens Immunity
High amounts of iodine intake can increase immune functions and keep a person vigorous in daily activities.
Study: Miller, DW (2006). Extrathyroidal benefits of iodine
Findings: The findings in this study suggest that iodine may have important effects not only on thyroid health but also on overall health.
Source: Journal of American Physicians and Surgeons, 11(4), 106.
Effective in the Synthesis of Thyroid Hormones
Since it plays a fundamental role in the synthesis of thyroid hormones, it regulates metabolism, controls energy production and ensures normal growth and development.
Study: Lazarus, J. H. (2015). The importance of iodine in public health.
Findings: This study investigates the health benefits of iodine. Its effect on thyroid hormone is emphasized.
Source: Environmental geochemistry and health, 37, 605-618
May Reduce Breast Cancer Risk
Some studies show that adequate iodine intake may reduce the incidence (risk of developing) breast cancer.
Study: Smyth, P. P. (2003). The thyroid, iodine and breast cancer.
Findings: This study examines a link between breast cancer and thyroid disease.
Source: Breast Cancer Research, 5, 1-4.
Improves Healthy Cells
It is necessary for the normal growth and development of cells, especially important for the healthy growth of children.
Study: Delange, F., & Lecomte, P. (2000). Iodine supplementation: benefits outweigh risks
Findings: This study showed that the benefits of iodine outweigh its risks and showed its benefits in cellular healing.
Source: Drug safety, 22, 89-95.
It is Beneficial During Pregnancy
Iodine supplementation during pregnancy may be beneficial in the context of normal intelligence development and learning ability.
Study: Monahan, M., Boelaert, K., Jolly, K., Chan, S., Barton, P., & Roberts, T. E. (2015). Costs and benefits of iodine supplementation for pregnant women in a mildly to moderately iodine-deficient population: a modeling analysis.
Findings: This study examines the benefits of iodine supplementation in pregnant women in a population with mild to moderate iodine deficiency.
Source: The Lancet Diabetes & Endocrinology, 3(9), 715-722.
Alleviates the Effects of Infection
Current evidence from clinical trials suggests that the benefits of iodine include fighting infections and thus promoting wound healing (especially in chronic and burn wounds), but it is not effective alone, especially with topical antibiotics.
Study: Vermeulen, H., Westerbos, S. J., & Ubbink, DT (2010). Benefit and harm of iodine in wound care: a systematic review.
Results: Iodine was more effective than other antiseptic agents (e.g. silver sulfadiazine cream) in some cases, but its effectiveness was limited in some cases when combined with topical antibiotics or alcohol.
Source: Hospital Infection, 76(3), 191-199.
Which Foods Contain Iodine?
Adolescents and adults need 150 micrograms of iodine daily. Fluid intake includes iodine from water and beverages, but food provides the majority of total iodine exposure.
Foods containing iodine can be grouped as follows:
- Seafood: Seaweed, fish (especially cod, tuna), shrimp.
- Dairy Products: Milk, yogurt, cheese.
- Iodized Salt: Table salt with added iodine.
- Eggs: Especially the yolk.
- Meat: Animal products with high iodine content.
- Fruits and Vegetables: Some plant foods such as seaweed, cranberries, potatoes, and lima beans.
Data on the iodine content of foods is quite limited, with the exception of milk and fish. The answer to the question of what contains iodine in general and the foods containing iodine are shown in the table below with their amounts:
| Food | Average Iodine Amount (mcg/100g) |
| Seaweed (nori) | 16 – 2,984 |
| Codfish | 99 |
| Prawn | 35 |
| Tuna | 17 |
| Oyster | 160 |
| Milk | 19 |
| Yogurt | 7 |
| Cheese | 11th |
| Egg | 12 |
| Beef | 12 |
| Chicken | 7 |
| Haricot bean | 32 |
| Potatoes (baked) | 60 |
| Dried plum | 13 |
| Iodized salt | 76 – 1,850 (per teaspoon) |
Study: Haldimann, M., Alt, A., Blanc, A., & Blondeau, K. (2005). Iodine content of food groups.
Findings: A detailed study on foods containing iodine is presented.
Source: Journal of food Composition and Analysis, 18(6), 461-471.
Study: Iodine
Findings: This resource highlights the importance of iodine-containing foods for health and emphasizes the importance of iodine intake.
Source: World’s Healthiest Foods (WHF)
What Foods Do Not Contain Iodine?
Iodine is naturally found in high amounts in some foods, such as seafood. There are also foods that do not contain iodine or contain very small amounts.
Depending on soil conditions, some vegetables and fruits may not contain iodine. These include foods such as apples, oranges, bananas, tomatoes, cucumbers and potatoes. Vegetable oils generally do not contain iodine. Products such as sugar, honey and artificial sweeteners do not contain iodine.
Here are some examples of foods that contain little or no iodine:
- Fresh Fruits and Vegetables: Apples, pears, peppers, broccoli.
- Cereals: Pasta, rice, bread (unless iodized salt is used).
- High Sugar Foods: Candy, chocolate, cake.
- Nuts and Seeds: Almonds, walnuts, sunflower seeds.
- Oils and Fatty Foods: Olive oil, butter.
Frequently Asked Questions About Iodine
What is the Use of Iodine in the Body?
Iodine is necessary for the synthesis of thyroid hormones, thyroxine (T4) and triiodothyronine (T3). With these hormones, the body regulates metabolism and provides energy. It also controls the oxidative capacity of body cells. Iodine is important for normal growth and development, especially during pregnancy, it is beneficial for the mental development of the baby.
Who is Affected by Iodine Deficiency?
People who consume less seafood or live in areas far from the sea are at higher risk of iodine deficiency. People who consume less iodized salt are more likely to develop iodine deficiency. Iodine deficiency can also reduce the production of thyroid hormones during pregnancy. In some areas, drinking water may have insufficient iodine content. This can also contribute to iodine deficiency.
How to Treat Iodine Deficiency at Home?
You can increase your iodine intake by replacing your daily salt intake with iodized salt . Iodized salt is widely available in many countries. Regularly consuming seafood such as fish and seaweed can increase your iodine intake.
How to Meet Daily Iodine Needs?
A balanced diet with iodine-containing foods helps meet your daily iodine needs. In some countries, milk and dairy products, especially yogurt, may be fortified with iodine. Choosing iodized milk and dairy products can help you meet your daily iodine needs. Certain amounts of iodine can also be found in nuts such as hazelnuts and walnuts, and legumes such as chickpeas and lentils.
Is There Iodine in Mineral Water?
Mineral water does not naturally contain iodine. However, some manufacturers may add iodine to mineral water. The minerals and amounts contained in mineral water may vary depending on the manufacturer.
What Happens If There Is Too Much Iodine in the Body?
Excess iodine can interfere with normal thyroid function. Especially in people with autoimmune thyroid diseases (such as Hashimoto’s thyroiditis or Graves’ disease), excess iodine can worsen thyroid function. It can also cause abnormal fluctuations in the thyroid hormones T3 and T4. This can affect functions such as metabolism, heart rate, and body temperature.
Who Should Take Iodine Supplements?
Women who are pregnant or breastfeeding can take iodine supplements. Individuals with thyroid diseases can consume iodine supplements as directed by their physicians. Additionally, individuals living in areas at high risk of iodine deficiency or those whose diets are deficient in iodine may consider iodine supplements.
Resources:
- Iodine Deficiency and Brain Development in Children:(Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. The Lancet Diabetes & Endocrinology. 2015).
- Iodine and Thyroid Function:(World Health Organization. Iodine in nutrition. WHO Technical Report Series).
- Impact of Iodine Deficiency on Health:(Andersson M, Karumbunathan V, Zimmermann MB. Global iodine status in 2011 and trends over the past decade. The Journal of Nutrition. 2012).
