Iodine is a trace mineral the body cannot make, yet it sits at the very heart of how we burn energy and grow. The thyroid gland gathers iodine from the diet and uses it to build the hormones that govern metabolism in almost every cell, and during pregnancy it is indispensable for a baby’s developing brain. The sea is its natural reservoir, so white fish such as cod, along with milk, yoghurt, cheese and eggs, are the everyday heroes. Both too little and too much can unsettle the thyroid, so balance is everything.
What is Iodine?
Iodine is a trace mineral that plays a critical role in supplying the raw material for the thyroid hormones thyroxine and triiodothyronine, which set the pace of metabolism in nearly every tissue and are essential for healthy growth and for normal brain development before birth and in early life. While many general diets overlook it, maintaining optimal levels of Iodine is frequently tracked by people working to optimize their Thyroid Function (TSH).
Top Foods High in Iodine
A data-driven breakdown of the foods with the highest concentration of Iodine per 100 g.
| Food | Iodine | % DV |
|---|---|---|
| Cod | 172 µg | 114.7% |
| Mussels | 105 µg | 70% |
| Parmesan | 82 µg | 54.7% |
| Greek Yogurt (plain, nonfat) | 51 µg | 34% |
| Mozzarella | 51 µg | 34% |
| Eggs | 49 µg | 32.7% |
| Cheddar Cheese | 46 µg | 30.7% |
| Cottage Cheese | 37 µg | 24.7% |
| Sardines | 35 µg | 23.3% |
| Mackerel | 34 µg | 22.7% |
| Whole Milk | 34 µg | 22.7% |
| Skim Milk | 34 µg | 22.7% |
| Shrimp | 16 µg | 10.7% |
| Kefir | 15 µg | 10% |
| Salmon (Atlantic) | 13 µg | 8.7% |
| Rainbow Trout | 11 µg | 7.3% |
| Tuna (canned, light) | 9.4 µg | 6.3% |
| Tilapia | 6.9 µg | 4.6% |
How Iodine Impacts Thyroid Function (TSH)
Research links diets rich in Iodine to changes in Thyroid Function (TSH). Optimizing intake of these foods can support healthy Thyroid Function (TSH) levels via supplying the iodine atoms that the thyroid gland incorporates into thyroxine (T4) and triiodothyronine (T3); adequate intake keeps hormone output steady so the pituitary need not raise thyroid-stimulating hormone, whereas a shortfall drives TSH up as the gland strains to compensate.
Scientific references & clinical evidence
This guide is built on peer-reviewed research — verify the primary sources below.
Written by the Nutrition Encyclopedia team · medically reviewed by Dr. Sunaina Tariq, MBBS
Last updated 22 June 2026
How we source & verify data · Medical disclaimer
Nutrition values are approximations compiled from public food-composition databases (USDA FoodData Central) and are provided for educational purposes only — not medical advice.
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