Iodine: Function, Reference Values & Natural Sources
Updated: Sep 21
What is iodine?
Iodine is an essential trace element. The body can't produce iodine on its own, so it needs to be taken in regularly through food. Iodine is needed to form thyroid hormones.
According to authorised health claims, iodine contributes to:
normal production of thyroid hormones
normal thyroid function
normal energy metabolism
normal function of the nervous system
maintenance of normal skin
normal cognitive function
normal growth in children
An adequate supply is important at every stage of life.
How much iodine is needed?
The recommended daily intake depends on age and life stage:
Life stage | Recommended intake per day |
0–6 months | 110 µg |
7–12 months | 130 µg |
1–8 years | 90 µg |
9–13 years | 120 µg |
14–18 years | 150 µg |
Adults | 150 µg |
Pregnant women | 220 µg |
Breastfeeding women | 290 µg |
Pregnant and breastfeeding women have an increased requirement.
Which foods contain iodine?
Iodine occurs naturally in certain foods and is sometimes added to table salt.
Sources of iodine include:
Sea fish and seafood
Seaweed/algae
Milk and dairy products
Eggs
Iodised table salt
Note: Many processed foods don't contain iodised salt. Speciality or gourmet salts are usually not iodised either. Whether a salt is iodised is stated on the label.
Iodine in dietary supplements
In dietary supplements, iodine is usually present as potassium iodide or sodium iodide. Multivitamin products may also contain iodine.
Dietary supplements are not a substitute for a balanced, varied diet and a healthy lifestyle.
Who should pay particular attention to an adequate intake?
An adequate iodine intake is fundamentally important for everyone. Certain groups should keep a particularly close eye on their intake, for example:
People who don't use iodised salt
People with a very low intake of dairy products, eggs or seafood
Pregnant and breastfeeding women
People with a one-sided diet
If you're unsure about your individual intake, it's a good idea to seek medical advice.
Can too much iodine be a problem?
Excessive iodine intake can also be undesirable. The tolerable upper intake levels per day are:
Life stage | Upper limit |
1–3 years | 200 µg |
4–8 years | 300 µg |
9–13 years | 600 µg |
14–18 years | 900 µg |
Adults | 1,100 µg |
These amounts refer to total intake from food and dietary supplements combined.
Higher-dose products should only be taken after consulting a doctor.
Important note
The information provided in this article is for general information purposes only. It does not constitute medical advice, diagnosis or treatment recommendations, and does not replace a consultation with a doctor.
The content is based on generally accessible scientific sources and publicly available specialist information.
Iodine's importance for the body and thyroid function.
Iodine's importance for the body and thyroid function
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