Jod: The most important questions and answers

Jod: Die wichtigsten Fragen und Antworten

Iodine is a vital trace element that is essential for the health of our human body. This chemical element, which is ingested through food, has been the subject of heated debate for years.

This article will provide clarity on the subject of iodine. In objective reporting, we answer the most important questions and clarify which alternative foods are ideally suited to prevent iodine deficiency.

the essentials in brief

  • Iodine is a natural trace element. However, this cannot be produced by the body itself and must be ingested through food. How much iodine you need depends on various factors.
  • The appearance of iodine deficiency can hardly be recognized at the beginning. Symptoms only appear clearly if the thyroid gland is severely underactive.
  • Foods such as iodised table salt, seaweed or certain types of fish have a high iodine content. The iodine balance can be covered with this.

Jod: What you should know

In the following we have selected and answered the most important questions on the subject of iodine. So you can find everything you need to know about iodine here.

What does our body need iodine for?

Iodine is a trace element that occurs naturally. It is also essential for human health. It is important for the body's own structure of the thyroid hormones thyroxine and triiodothyronine.

These hormones are instrumental in controlling some processes in the body. These include growth, bone formation, brain development and energy metabolism (1).

How much iodine do you need per day?

How much iodine you actually need per day depends on various factors. These include age, environmental pollution (smoking, nitrate) and a high consumption of plant-based foods containing goitrous (goiter-forming) substances.

These factors require corresponding safety margins when deriving the recommendations (2).

Old Recommended iodine intake (in μg/day)
up to 4 months 40
4-12 months 80
1-4 years months 80
4-7 years 100
7-10 years 120
19-13 years 140
13-15 years 180
15-51 years 200
51 years and older 180


What are the signs of iodine deficiency?

An iodine deficiency can already affect the development of the embryo and the fetus, which can have serious neurological consequences. With an enlargement of the thyroid gland, iodine deficiency often manifests itself in adults or in childhood.

Knots are often formed in the process. If the iodine deficiency is only slight, the thyroid gland is enlarged, but the thyroid gland functions normally. As a result, iodine deficiency can lead to a change or disorder in the thyroid gland(4).

Exhausted woman lies on the couch

Iodine deficiency can manifest itself in a wide variety of symptoms. (Image source: zohre nemati/ Unsplash)

In Germany, too, there was hypothyroidism with storma due to iodine deficiency, but today it is only widespread in some developing countries. A thyroid, which is usually caused by iodine deficiency, is called sturma. A sturma without knots is called strma diffusa, a sturma with knots is called sturma nodosa (5).

Initially, those affected hardly notice any symptoms of iodine deficiency. The symptoms only become apparent when the thyroid gland is underactive. These can include:

  • severe fatigue
  • lack of drive
  • growth disorders
  • difficulty concentrating
  • Difficulty breathing and swallowing
  • change in the skin
  • feeling of pressure in the neck
  • Developmental disabilities (6)

What contains a lot of iodine?

The amount of iodine in foods can vary from region to region. The iodine content depends on the soil and water. Production conditions can also be responsible. These include, for example, plant fertilization or the iodine content in animal feed.

A significant source of iodine in Germany is iodised table salt, which is also available in standard supermarkets. Since the late 1980s, it has also been approved for use in food processing and in mass catering.

Naturally high levels of iodine are found almost exclusively in sea creatures and seaweed. In addition to iodised table salt, bread and non-alcoholic beverages are important plant sources of iodine (7.8">.

Groceries Iodine content mg/kg
algae 5-11000
Nori seaweed 16
Iodized table salt 15-25

Seaweed can be used in many ways in the kitchen. Especially in Asian cuisine, healthy dishes can be created. (Image source: daniel apodacca/ Unsplash)

How important is iodine for the thyroid?

Organic and inorganic iodine, which is ingested with food, is almost completely absorbed in the small intestine. Depending on the iodine concentration, it is actively taken up by the thyroid into the thyroid cells. If the thyroid becomes saturated with iodine, the excess iodine is excreted through the kidneys.

The thyroid consists of small "sacs" surrounded by hormone-producing cells. The NIS is located on the outer membrane of these cells. The iodide is transported through the cell by a mechanism and released into the sacs.

High doses of iodine directly inhibit NIS activity. With this it can be achieved that with healthy thyroid glands there is always sufficient, but never too much iodide intake, and thus no overactive thyroid gland develops.

For this reason, iodine is essential for the thyroid hormone. Since the human body cannot produce iodine on its own, it must be supplied (9).

What is the importance of iodine during pregnancy and breastfeeding?

Sufficient iodine supply is of enormous importance, especially during pregnancy and breastfeeding. During this time, the iodine requirement of the pregnant woman as well as that of the child must be ensured.

Iodine intake in general Iodine intake has improved significantly over the years, but the desirable intake of 230 µg per day is often not achieved in pregnant women and 260 µg in breastfeeding women.

Even the use of iodized salt in the household is not sufficient. For this reason, iodine tablets are considered important for pregnant and breastfeeding women.

Iodine deficiency during pregnancy increases the rate of miscarriages, stillbirths and malformations. The early childhood development of the central nervous system, as well as body growth and maturation, depend on an adequate supply of iodine.

Iodine is therefore an important element that can influence the development of the child. Getting the right amount isn’t just important in adulthood (10).

What factors influence iodine intake?

Iodine is only found in large quantities in the sea and in hot springs from deep within the earth. These include algae. Algae concentrate iodide from seawater about 3,000 times and then bind it.

Under special conditions such as B. by solar radiation or mechanical stimuli (such as spray on the coast), algae release various inorganic iodine compounds, which then get into the atmosphere. The iodine reaches the mainland through rain (11).

It can thus be stated that regions close to the sea are better supplied with iodine than regions further away from the sea. This is a factor that particularly affects iodine intake.

What health causes can iodine excess have?

In one study, volunteers were given 1000 or 2000 µg of iodide per day for 12 weeks in addition to their normal diet, which contains up to 350 µg of iodide.

As a result, extremely high doses of iodine do not harm a healthy thyroid. There were no side effects on the skin or on the digestive system. Thyroid function was also not significantly affected (12).

However, chronic intake of 10 to 50 mg iodide per day can lead to prolonged inhibition of thyroid function and the development of hypothyroidism. This was found on the Hokkaido peninsula in Japan by consuming a large amount of algae, which is particularly rich in iodine (13).

What alternatives are there to prevent iodine deficiency?

A balanced diet is required to meet the daily iodine requirement. It is just as important to minimize iodine intake if the iodine content is to be controlled.

Animal products:

Animal foods such as fish, milk or eggs contain high levels of iodine. These include fish fingers, cod or plaice. Iodine is also contained in feta made from sheep's cheese, whole milk or sour cream. Meat, on the other hand, is very low in iodine. If you should avoid iodine, you can use beef, pork or chicken for this reason.

Seaweed: Seaweed is one of the best sources of iodine.

Salt: Iodized salt is one of the best sources of iodine. With just a few grams, the need can be well covered.

Legumes: Among the legumes, green beans and peas are the richest in iodine.

Nuts: Cashews and peanuts contain iodine. However, the amount is very limited.

Vegetables: Vegetables themselves contain little iodine. Kale, spinach and broccoli have the highest iodine content.

Cereals: When it comes to cereals, mixed cereals or rye are the best sources of iodine. All other grains contain very little to no iodine.

Dietary supplements: Dietary supplements intended to balance the iodine balance can also be purchased (7).

Which foods are best for you must be decided individually. It is best to consult a doctor and draw up a plan with the right foods for you.

Bowl full of fish

Iodine deficiency can be prevented with a balanced diet. Iodized salt is particularly suitable for this. (Image source: stefan johnson/ Unsplash)


Iodine is an extremely important trace element, which is essential for the functioning of our body. However, iodine cannot be produced by our body itself. For this reason, the right diet is particularly important! How much iodine we actually need varies from person to person.

In addition to age, factors such as environmental pollution and personal nutrition play an important role. Iodine is also essential during pregnancy. For this reason, the iodine intake usually has to be increased to ensure the health of the child and the mother.

Iodised table salt and seaweed are particularly foods that contain iodine. With this, the iodine requirement can be covered quickly. If you want to rely on animal foods, you will make the right choice with some types of fish.

Cheese and eggs are also suitable for this. It is important to see a doctor if you notice any symptoms. Thus, the clinical picture can be determined individually.


  1. Patrick L. Altern Med Rev. 2008 Jun;13(2):116-27. PMID: 18590348 Transfer title to Citavi project using this Pubmed ID.
  2. Roland Gaertner, Munich. Training & education, iodine and thyroid. 12/2015 .
  3. Max Rubner Institute (ed.) (2008): National Consumption Study II. Results Report, Part 2. Karlsruhe, p. 138f
  4. Gärtner R, Dugrillon A (1998) From iodine deficiency to goiter. Pathophysiology of iodine-deficiency goiter. Internist 39: 566-573
  5. Führer D, Bockisch A, Schmid KW (2012) Euthyroid goiter with and without node diagnosis and therapy. Dtsch Ärztebl Int 109: 506-516
  6. Importance of iodine for the thyroid. AUTHOR: Prof. Dr. medical Hans Udo Zieren.
  7. Wolfgang Buchinger, Gleisdorf/Graz and Georg Zettinig, Vienna: On behalf of the iodine supply working group of the Austrian Thyroid Society. Sandoz GmbH, Stella-Klein-Löw-Weg 17, 1020 Vienna, Austria
  8. Prof. Dr. D. Hotzel. Director of the Institute for Nutritional Science at the University of Bonn. Vitamins, minerals, trace elements in medicine, nutrition and the environment. Publisher: K. Schmidt. Hippocrates Verlag Stuttgart. 1987
  9. Dal G, Levy O, Carrasco N (1996) Cloning and characterization of the thyroid iodide transporter. Nature 379:458-459
  10. Iodine, folate/folic acid and pregnancy. Federal Institute for Risk Assessment. 10609 Berlin Phone +49 30 18412-0 • Fax +49 30 18412-4970 [email protected] •
  11. Saunders RW, Saiz-Lopez A. Iodine in the air: Origin, transformation, and exchange to mammals. In: Preedy VR, Burrow GN, Watson RR (eds). Comprehensive handbook of iodine-nutritional, biochemical, pathological and therapeutic aspects (2009), pp. 75-82
  12. Braverman LE (1994) Iodine and the thyroid: 33 years of study. Thyroid 4: 351-356
  13. Suzuki H, Higuchi T, Sawa K et al. (1965) Endemic coast goiter in Hokkaido, Japan. Acta Endocrinol 50:161-176
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