What Foods Have Potassium Iodide In Them? A Full Guide to Dietary Sources

January 4, 2026 •

4 min read

The World Health Organization has long supported salt iodization programs, recognizing them as a safe and effective strategy for preventing iodine deficiency disorders globally. For this reason, many of the world's most readily available sources of dietary iodine come from fortified foods.

Quick Summary

Discover common and fortified food sources of potassium iodide, including iodized table salt, seaweed, and dairy. Understanding these dietary options is essential for supporting healthy thyroid function and overall well-being.

Key Points

Iodized Salt: This is the most common dietary source of potassium iodide, which is added as a fortifying agent to prevent iodine deficiency.
Seaweed is a Natural Source: Marine vegetables like kelp and nori contain high levels of naturally occurring iodine, sometimes in the form of potassium iodide, though content can vary significantly.
Dairy and Seafood Provide Iodine: Milk, yogurt, cheese, fish, and shellfish are excellent natural sources of iodine, with levels influenced by diet and environment.
Fortification is Key: The iodine content in many foods, including some breads and infant formulas, comes from fortification with potassium iodate or potassium iodide.
Balanced Intake is Important: Ensure you are consuming a variety of these sources to maintain adequate iodine levels for thyroid function without overconsumption, especially with highly concentrated items like kelp.

What is Potassium Iodide?

Potassium iodide, often abbreviated as KI, is a chemical compound used to provide the essential trace mineral iodine. While the body needs iodine, it cannot produce it on its own, making dietary intake crucial. Iodine is vital for the thyroid gland, which uses it to produce hormones that regulate metabolism, growth, and development.

Although elemental iodine is present in some foods, potassium iodide is the most common form added to fortify products like table salt. It is also found naturally in some marine foods, where iodine is absorbed from the seawater environment. Understanding which foods contain this specific compound or are rich in iodine from other sources is key to a balanced diet.

Fortified Foods Containing Potassium Iodide

Iodized Salt

For most people, the most common source of potassium iodide is iodized table salt. Since the 1920s, many countries have voluntarily added potassium iodide (or potassium iodate) to table salt to help prevent iodine deficiency. A quarter teaspoon of iodized salt can contain a significant portion of the recommended daily value for iodine.

How to identify: Look for the word "iodized" on the salt packaging. Specialized salts, such as sea salt, kosher salt, or Himalayan salt, are typically not iodized unless the label specifies it.
Consideration: Because most processed and pre-packaged foods use non-iodized salt, home cooking with iodized salt is a simple way to ensure adequate intake.

Certain Commercial Breads and Cereals

Some commercial baked goods and fortified cereals may contain potassium iodate or calcium iodate as a dough conditioner.

Ingredient Check: The label must list the specific dough conditioner, though it is not mandatory to list the iodine content on the Nutrition Facts panel.
Variability: The iodine content can vary widely between brands and types of bread, so this is not a consistent source unless confirmed.

Infant Formula

To support proper growth and neurological development, manufacturers fortify most infant formulas with iodine, often using potassium iodide.

Natural Sources of Iodine

While not strictly containing the compound potassium iodide, these natural foods are excellent sources of dietary iodine, which the body utilizes in the same way.

Seaweed and Other Sea Vegetables

Seaweed is arguably the most concentrated natural food source of iodine, and it contains it in various iodide forms, including potassium iodide.

Kelp: The highest iodine content is often found in kelp, with even small amounts exceeding daily requirements.
Nori, Kombu, and Wakame: These popular seaweeds, used in sushi and soups, are also rich sources, but the iodine content can vary significantly based on species and preparation.

Seafood and Fish

Marine fish and shellfish naturally contain iodine absorbed from seawater. The amount can vary, but these are reliable sources for a healthy diet.

Examples: Cod, haddock, shrimp, and tuna (canned in water) are some of the best seafood options.

Dairy Products

Dairy products are good sources of iodine, but the levels depend on several factors, including the cow's feed and the sanitizers used in milk processing.

Milk, Yogurt, and Cheese: These products can all provide a notable amount of iodine, contributing to daily intake.
Vegan Alternatives: Plant-based milk alternatives, like soy or almond milk, generally contain very little iodine unless fortified. Some fortified versions may add potassium iodide.

Eggs

Eggs are a good source of iodine, with the mineral concentrated in the yolk. A single large egg can provide a decent percentage of the daily value.

Fruits and Vegetables

The iodine content of produce is highly dependent on the iodine levels of the soil where it is grown. Therefore, fruits and vegetables are generally considered unreliable sources of iodine unless grown in iodine-rich areas.

Iodine Content Comparison Table


Food Source	Iodine Content (per serving)	Main Source of Iodine	Notes
Iodized Table Salt	78 mcg per ¼ tsp	Fortified with Potassium Iodide	Easy to control intake during home cooking.
Seaweed (e.g., Kelp)	Up to 2000+ mcg per serving	Natural compound	Highly variable; consume with caution to avoid excess.
Cod, baked (3 oz)	146 mcg	Natural compound	One of the most reliable seafood sources.
Yogurt, plain (¾ cup)	87 mcg	Natural (from feed/processing)	Good source for those consuming dairy.
Milk (1 cup)	~84 mcg	Natural (from feed/processing)	A common and consistent source.
Egg, hard-boiled (1 large)	31 mcg	Natural compound	Yolk contains the most iodine.
Canned Tuna (3 oz)	7 mcg	Natural compound	Lower source, but still a contribution.
Fruits & Vegetables	Highly variable, often low	Natural (from soil)	Not a dependable source due to soil differences.

How to Ensure Adequate Intake

For most people, a balanced diet that includes iodized salt is sufficient to prevent deficiency. However, individuals on a low-sodium diet, vegans, or those who rarely eat seafood or dairy may need to be more mindful of their iodine intake. Pregnant and lactating women have higher iodine requirements and should consult a healthcare provider to ensure they meet their needs, often through supplements.

Conclusion: Finding the Right Balance

In conclusion, foods containing potassium iodide, primarily iodized table salt and fortified products, are a simple way to maintain proper iodine levels. Combining these with naturally iodine-rich foods like seaweed, seafood, and dairy ensures a well-rounded and sufficient intake. A balanced diet and careful label reading are the best strategies to meet your body's essential iodine requirements for a healthy thyroid and overall well-being. For medical advice on supplementation, consult with a qualified health professional.

For more detailed information on recommended daily allowances and sources, visit the NIH Office of Dietary Supplements website.

Frequently Asked Questions

Potassium iodide is a specific chemical compound containing iodine. While all potassium iodide contains iodine, not all iodine is in the form of potassium iodide. The body uses the iodine from either source for thyroid hormone production.

Adding potassium iodide to table salt is a public health measure to ensure widespread access to a dietary source of iodine, which is crucial for preventing iodine deficiency and related health problems.

No. Only salt labeled 'iodized' contains added potassium iodide. Sea salt, kosher salt, and other specialty salts are generally not iodized unless specifically stated on the packaging.

A vegan diet can be low in iodine, as many common sources like dairy and seafood are excluded. Vegans must be mindful to consume fortified plant-based milks or take a supplement, often containing potassium iodide.

Yes. While rare from food alone, excessive iodine intake, especially from high-dose supplements or large quantities of kelp, can cause thyroid dysfunction in sensitive individuals.

The recommended daily intake of iodine for most adults is 150 micrograms (mcg). This increases to 220 mcg for pregnant women and 290 mcg for breastfeeding women.

Some iodine can be lost during cooking, particularly from prolonged boiling. However, adding iodized salt to food during cooking still provides a reliable source of iodine.