Iodine is a mineral essential for thyroid health. Although many types of seafood are rich in iodine, it is also present in eggs, dairy products, and some plant foods.

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In addition to foods containing naturally occurring iodine, people can consume the mineral through fortified sources. Iodized salt is a common source.

Consuming enough iodine is important for a healthy thyroid. The thyroid is responsible for hormone regulation, metabolism, nervous system health, and more.

If a person is deficient in iodine it can harm their health. Adeficiency is particularly dangerous for pregnant women.

Read more to learn about 13 iodine-rich foods, how much iodine a person should consume, and the risks of consuming both too much and too little of this mineral.

1. Seaweed

Seaweed is full of naturally occurring iodine and contains about 232 micrograms (mcg) per serving. That’s more than the 150 mcg recommended daily intake (RDI) for men and non-pregnant females.

Seaweed’s high iodine content is thanks to its ability to absorb concentrated iodine from the ocean.

2. Cod

In general, seafood is a good source of iodine. However, cod is particularly high in this essential mineral. One serving, or 3 ounces (oz.) of cod contains roughly 158 mcg of iodine, meeting the RDI for most adults.

Researchers have found that the body of water the fish lives in determines how much iodine cod contains. For example, cod from the Norwegian Sea had more iodine than Atlantic cod from the North Sea.

3. Halibut

Halibut is another seafood high in iodine. Research shows that Atlantic halibut contains about 21 mcg of iodine per serving. Although that is less than some other fish, it still provides a good amount of iodine.

4. Pollock

Pollock is a member of the cod family that frequents the cold waters of the North Pacific. A 120 gram (g) serving of Alaskan pollock provides around 67 mcg of iodine, which is about half of the RDI.

It also contains omega-3 fatty acids, phosphorus, selenium, and niacin, which all contribute to immune and nervous system health.

5. Crab

Though crab contains less iodine than other seafood, it still provides between 26 and 50 mcg in a 100 g serving.

Besides being a good source of protein, crab also contains many other essential nutrients. It provides selenium, B12, and zinc.

6. Scallops

Scallops are a great source of iodine. They provide 135 mcg per serving, which is 90% of the RDI. They may also be beneficial for heart health and the central nervous system.

7. Squid

Squid, commonly consumed as calamari, contains about 65 mcg per serving. It is also a good source of Vitamin C, iron, and calcium, and omega-3 fatty acids.

8. Tuna

Because tuna is a fattier fish than other varieties, it contains less iodine. However, at 17 mcg per 3 oz. serving, it is still a decent source of the mineral.

Tuna is an accessible, relatively affordable source of iodine that people may find easier to add to their diet than some other seafood.

9. Milk

Dairy products are also a good source of iodine. For example, one cup of nonfat cow’s milk on average contains 85 mcg, which is more than half the RDI.

Despite this, an abstract from a 2017 study states that the actual iodine concentration in milk products varies greatly. Factors influencing the total concentration include milk yield, season, and whether the farmer engages in teat-dipping with iodine-containing disinfectants. This means milk has a variable amount of iodine.

10. Cheese

Certain types of cheese provide more iodine than others. However, on average, cheese contains 37.5 mcg of iodine per 100 g of cheese.

11. Yogurt

Like other dairy products, yogurt is a good source of iodine. Just one cup of plain Greek yogurt provides up to 116 mcg of iodine.

12. Eggs

Eggs — specifically egg yolks — are a good source of iodine. Typically, one large egg contains 26 mcg of iodine.

13. Iodized salt

Perhaps the most popular and plentiful source of iodine in the average person’s diet is iodized salt. It takes just over half a teaspoon of iodized salt to get the RDI of iodine.

This is one of the most convenient and affordable ways to prevent iodine deficiency. It is a particularly good source of iodine for people who follow plant-based diets, as plant foods are generally a poor source of iodine.

Iodine is an essential mineral for thyroid regulation. Without sufficient iodine, people may experience issues like weight gain, excessive fatigue, hair loss, dry skin, and cognitive impairment.

The presence of the mineral in iodized salt makes some people think that sodium and iodine are synonymous. However, this is not true. Classic table salt is available with and without iodine, and many popular salts, like sea salt and pink Himalayan salt, do not contain iodine.

According to the National Institutes of Health (NIH), the recommended daily intake for iodine is 150 mcg in adult men and women. In the United States and Canada, just one teaspoon of iodized salt contains 250 mcg. This makes it relatively easy to meet the RDI.

It is important to note the iodine recommendation for pregnant females is significantly higher, at 220 mcg.

Because the risk of iodine deficiency drastically increases during pregnancy, the American Thyroid Association recommends that people planning on becoming pregnant take a daily prenatal vitamin containing at least 150 mcg of iodine.

People most at risk for iodine deficiencies are pregnant females and people who consume diets low in sodium.

Failure to consume an adequate amount of iodine each day could result in long-term thyroid problems. Goiter, hypothyroidism, and pregnancy complications can all result from an iodine deficiency.

Learn more about the signs of iodine deficiency.

Consuming too much iodine can also be problematic. A diet containing excess iodine is associated with thyroid gland inflammation and thyroid cancer. The damage from a high-iodine diet occurs over time.

Additionally, eating a very large serving of iodine at one time can result in short-term discomfort. A person may experience burning of the mouth and stomach, fever, nausea, and diarrhea.

People who take iodine supplements should ensure the product contains only the RDI, or less, in order to avoid consuming too much iodine.

Iodine is a mineral found in foods such as seafood, dairy products, and seaweed. It is essential for regulating thyroid function.

An iodine deficiency can cause serious long-term conditions and side effects, such as goiter and hyperthyroidism.

Pregnant people, or those planning on becoming pregnant, are at particularly high risk. They should take a prenatal vitamin with iodine and include a variety of iodine sources in their diet to ensure they do not develop a deficiency.

Typically, incorporating just a teaspoon or less of iodized salt into a person’s diet provides adequate iodine.