Iodine
I · last AI check: 2026-07-19
In short
Needed for thyroid function. In much of Europe it is supplied partly through iodised salt.
What it does in the body
The sentences below are officially authorised EU health claims.
Iodine contributes to the normal production of thyroid hormones and normal thyroid function EU health claim
Commission Regulation (EU) No 432/2012 of 16 May 2012, Annex — list of permitted health claims · register entry: 274, 1237 · EFSA opinion: 2009;7(9):1214; 2010;8(10):1800
Condition of use on a product: The product is at least a source of Iodine.
How much you need
| Country / organisation | Group | Value | Type |
|---|---|---|---|
| EFSA | adults | AI Adequate intake — an approximate value used when data are insufficient to set an exact requirement (RDA). | |
| FAO | adult men | RNI Reference nutrient intake — the RDA equivalent in WHO/FAO, UK and Philippine terminology. | |
| NASEM (US/CA) | adults | RDA Recommended daily allowance — covers the needs of almost all healthy people in a group. | |
| Philippines | adults | RNI Reference nutrient intake — the RDA equivalent in WHO/FAO, UK and Philippine terminology. | |
| India | adults | RDA Recommended daily allowance — covers the needs of almost all healthy people in a group. | |
| Poland | adults | RDA Recommended daily allowance — covers the needs of almost all healthy people in a group. | |
| Switzerland | adults | RDA Recommended daily allowance — covers the needs of almost all healthy people in a group. | |
| United Kingdom | adults | RNI Reference nutrient intake — the RDA equivalent in WHO/FAO, UK and Philippine terminology. |
Reference values from different countries are not directly comparable — they differ in definition and age group. How to read reference values →
Every value states its source — click it to see the document, location and link.Data and content are prepared and cross-checked against source documents by several independent AI models. They have not been audited by a human editor.Before citing a value, check it in the source document — verification is automated (AI), not editorial.
Worth knowing
Iodine is the building block of thyroid hormones — and that's practically where its role in the body ends. Few elements have such a narrow yet such an essential job.
Why salt is iodised
The iodine content of food depends on how much is present in the soil and water, and it is often scarce in areas far from the sea. Historically, this led to widespread deficiencies in inland and mountainous regions. The response in many countries, including Poland, was mandatory iodisation of table salt — one of the most widely applied public health programmes in nutrition.
This has a consequence that's easy to forget: recommendations to cut down on salt and the salt-iodisation programme work in opposite directions. People who consistently cut salt, and who also use non-iodised salt — Himalayan, sea or rock salt — lose their main dietary source of iodine along the way, usually without realising it.
The safety range works both ways
With iodine, both deficiency and excess are harmful — both can disrupt thyroid function, though through different mechanisms. This is why supplementing iodine “just in case”, especially with high-content preparations or seaweed extracts, isn't a neutral act.
Requirements also change during pregnancy and breastfeeding, and deficiency at this time has particular significance for the child's development — this is one of the situations where recommendations are formulated separately. If you have a thyroid condition, are pregnant, or are considering iodine supplementation, discuss it with a doctor; with thyroid conditions, dosing is sometimes individual.
Where to find it
iodised salt · sea fish · dairy products
This material is for information and education. It does not replace advice from a doctor or dietitian. For health matters, consult a qualified medical professional.