Sources of Iodine for Adults

Dairy products and seafood are the richest dietary sources of iodine and their consumption is essential to support adequate iodine status. 1

Primary Dietary Sources

Dairy products are among the richest sources of iodine and should be prioritized in the diet 1
Seafood, particularly shellfish, provides high iodine content and represents a key dietary source 1, 2
Fish is a reliable source of iodine for meeting daily requirements 3
Lean meat, liver, and black pudding contain iron but seafood remains the primary animal source for iodine 1

Iodized salt is a major source, containing approximately 60 mcg of iodine per gram of salt 1
More than 120 countries have implemented salt iodization as a public health strategy 1
Fortified bread is available in some countries with mandatory fortification programs 1

Certain seaweeds can provide iodine, though amounts vary widely 4
Vegetables and whole grains contain minimal iodine and should not be relied upon as primary sources 1

Iodine supplements should provide 150 mcg daily for adults in iodine-deficient populations 5
Pregnant and lactating women require mandatory supplementation of 150 mcg iodine daily in iodine-deficient regions 5
The WHO supports supplementation during pregnancy when mandatory salt iodization is not present 1
Prenatal vitamins containing 150 mcg iodine are recommended during preconception, pregnancy, and lactation in some countries 1

Iodine is well absorbed orally or enterally (approximately 300-600 mcg/day) 1
Intramuscular injection is an alternative delivery method 1
For acute severe deficiency, intravenous sodium iodide solution can be administered 1

Adults need at least 150 mcg of iodine per day, with an upper safe limit of 300 mcg in standard nutrition regimens 1
Enteral nutrition should provide 150-300 mcg iodine per 1500 kcal 1

Do not assume vegetables or non-iodized salt provide adequate iodine—55% of UK mothers incorrectly identified these as iodine-rich foods 1
Be aware that iodine-rich foods (dairy and seafood) currently contribute only about 13% of average energy intake in adult women, indicating they need to be repositioned in the diet 1
Avoid excessive iodine intake from non-nutritional sources including iodinated contrast agents, topical povidone-iodine disinfectants, and amiodarone, which can cause thyroid dysfunction 1, 5

Iodine status should be assessed by 24-hour urinary iodine excretion (normal: 100-300 mcg/24hr) combined with thyroid function tests 5, 4
Median urinary iodine concentration reflects total iodine intake from all sources at the population level 4

The UK is listed as one of the ten countries with the lowest iodine status globally, with approximately 60% of pregnant women not meeting WHO recommended intake 1
In iodine-sufficient populations like the United States, dairy products and iodized salt remain the major dietary sources 3
About 50% of Europe remains mildly iodine deficient despite fortification efforts 6