Foods High in Iodine: Iodized Salt, Seaweed, Dairy, Fish and Eggs
Which foods supply iodine, with amounts per serving from NIH and NHS sources, why seaweed and dairy vary so much, and where too much iodine can become a problem.
Content last updated . This page has not been medically reviewed.
All amounts below are micrograms (mcg, the same as µg) of the element iodine, not of a compound. This page gives information only. It is not advice about how much anyone should eat.
Iodine in selected foods
The table comes from the NIH Office of Dietary Supplements fact sheet, which draws on a US government iodine food database. [3] The amounts are US averages for the serving shown. Other countries, brands and farms can differ.| Food and serving | Iodine (mcg) | Source |
|---|---|---|
| Cod, baked, 3 ounces | 146 | NIH ODS, snapshot of 2 Jan 2026 [3] |
| Nori seaweed, dried, 2 tablespoons flaked (5 g) | 116 | NIH ODS [3] |
| Oysters, cooked, 3 ounces | 93 | NIH ODS [3] |
| Greek yogurt, plain, nonfat, three-quarters of a cup | 87 | NIH ODS [3] |
| Nonfat milk, 1 cup | 84 (range 38 to 160 in 59 samples) | NIH ODS [3] |
| Iodized table salt, one quarter teaspoon | 78 | NIH ODS [3] |
| Egg, hard boiled, 1 large | 31 | NIH ODS [3] |
| Cheddar cheese, 1 ounce | 14 | NIH ODS [3] |
| Canned tuna in water, 3 ounces | 7 | NIH ODS [3] |
| Soy beverage, 1 cup | 3 | NIH ODS [3] |
| Non-iodized sea salt, one quarter teaspoon | 0 | NIH ODS [3] |
The NHS (UK) lists cows' milk and dairy products, eggs, sea fish and shellfish as good sources, and says iodine in cereals and grains depends on the soil. [1] MedlinePlus names cod, sea bass, haddock and perch as good seafood sources. [2]
Iodized salt
MedlinePlus calls iodized salt the main food source and says to look for "iodized" on the label. [2] NIH ODS says that in the United States most salt eaten comes from processed foods, and manufacturers almost always use non-iodized salt in those foods. [3] Sea salt is not automatically iodized: the table above lists non-iodized sea salt at zero. [3] For the history of salt iodization see Iodized salt and public health.Seaweed: the widest range
NIH ODS says seaweed such as kelp, nori, kombu and wakame is one of the best food sources, and that whole or sheet seaweeds ranged from 16 to 2,984 mcg of iodine per gram. [3] A Norwegian laboratory study of 96 seaweed products found 128 to 62,400 mcg of iodine in one portion of whole seaweed products. For 54 products, one portion or dose would exceed the tolerable upper intake level. The authors also found labelling that was inadequate or inaccurate for several products. [4]The upper level for iodine for adults is 1,100 mcg a day, according to NIH ODS for the United States and Health Canada. [3] [5] Kelp and seaweed supplements are covered on Kelp and seaweed supplements.
Dairy, bread and plant-based foods
NIH ODS says dairy iodine varies with cow feed and with iodine-containing cleaning agents used on equipment. It also says plant-based milk substitutes such as soy and almond drinks contain relatively small amounts. [3] The NHS notes some soya and oat drinks are fortified, so the label is the thing to check. [1] Bread contains very little iodine unless the maker used an iodate dough conditioner, and iodine is not required on the Nutrition Facts label even then. [3]Official intake levels
| Group | Amount | Source and year |
|---|---|---|
| Adults 19 and over, UK | 140 mcg a day | NHS, page reviewed 2020 [1] |
| Males and females 14 and over, US (RDA) | 150 mcg a day | MedlinePlus, review 2025 [2] |
| Pregnancy, US (RDA) | 220 mcg a day | MedlinePlus, review 2025 [2] |
| Breastfeeding, US (RDA) | 290 mcg a day | MedlinePlus, review 2025 [2] |
| Adults, upper level, US and Canada | 1,100 mcg a day | NIH ODS, Health Canada 2025 [3] [5] |
The NHS says most people can get what they need from a varied diet, and that a strict vegan diet with no fish, eggs or dairy is a reason to ask a healthcare professional about fortified foods or a supplement. [1]
Related pages
For a cross-reference of iodine, zinc, selenium and copper foods see Trace minerals in food. The full profile is Iodine, and the library home is Minerals.Frequently asked questions
Which foods have the most iodine?
Seaweed has the highest and most variable amounts: one lab study found 128 to 62,400 mcg in a portion of whole seaweed products. [4] Among everyday foods, NIH ODS lists baked cod at 146 mcg per 3 ounces and a cup of nonfat milk at about 84 mcg. [3]
Is sea salt a good source of iodine?
Not unless it is labelled iodized. NIH ODS lists non-iodized sea salt at 0 mcg per quarter teaspoon, against 78 mcg for iodized table salt. [3]
Do dairy-free or vegan diets provide enough iodine?
The NHS says that if you eat no fish, eggs, cows' milk or dairy, you may want to consider iodine-fortified foods or ask about a supplement. Some plant drinks are fortified, so check the label. [1]
Can you get too much iodine from food?
Yes, mainly from seaweed and kelp products. A Norwegian study found that one portion or dose of 54 of 96 products would exceed the tolerable upper intake level. [4] Long-term high intake can disturb thyroid function. [3]
Should I test my iodine or change my diet myself?
Symptoms do not show iodine status, and thyroid conditions need a clinician. Ask a doctor or pharmacist before using iodine or kelp supplements, especially in pregnancy, with thyroid disease or with thyroid medicines. [3]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Cautions
- Too much iodine can affect the thyroid. NIH ODS says high intakes can cause goiter, high TSH and an underactive thyroid, and can also cause an overactive thyroid. People with autoimmune thyroid disease may react to amounts that are fine for others. [3] See Iodine and the thyroid.
- Medicines. High iodine with antithyroid medicines can add up and cause an underactive thyroid. [3] Ask a pharmacist, and see Medication interactions.
- Pregnancy and breastfeeding raise needs, and NIH ODS describes iodine deficiency as harmful to neurological development. [3] See Iodine in pregnancy and breastfeeding and talk with a midwife or doctor.
- Radioactive iodine treatment. Teams sometimes ask patients to follow a low-iodine diet before it. NIH ODS lists seafood, seaweed, dairy, eggs and iodized salt among the foods to avoid, but the instructions come from your own care team. [3]
- Kidney and liver disease. The sources we read for this page did not address iodine foods in these conditions, so ask your clinician.
References
- NHS, Vitamins and minerals: Iodine (UK; page last reviewed 3 August 2020). Read 2026-10-23.
- MedlinePlus Medical Encyclopedia, Iodine in diet (US; review date 1/21/2025). Read 2026-10-23.
- NIH Office of Dietary Supplements, Iodine: Fact Sheet for Health Professionals (US). The ODS site blocked direct download, so this was read from an Internet Archive copy captured 2 January 2026. Read 2026-10-23.
- Aakre I et al., Commercially available kelp and seaweed products: valuable iodine source or risk of excess intake? Food Nutr Res 2021 (abstract read). Read 2026-10-23.
- Health Canada, Dietary reference intakes tables: reference values for elements (page dated 2025-11-19; read through a web-fetch tool that summarizes pages). Read 2026-10-23.