The 7 Iodine-Rich Foods

Iodine is an essential mineral — your body has to have it. And whenever I can, I'd rather you get a nutrient from real food than from a supplement. So let's talk about where iodine actually comes from in your diet.

One thing to understand up front: the iodine content of food isn't fixed. It depends heavily on where the food grew or where the animal lived. Sea fish can be rich in iodine while freshwater fish may have very little. Even seaweed varies depending on which ocean it came from and whether it was wild or farmed. So don't just look at the name of a food — look at its source.

1. Sea Fish

Fish that swim in the ocean are one of the best natural sources of iodine, because the ocean itself is a major source. I generally prefer smaller ocean fish that aren't large predators, since they tend to accumulate less mercury and fewer heavy metals than big predatory fish like swordfish. As a bonus, ocean fish also provide omega-3 fatty acids and other nutrients.

2. Sea Crustaceans

Shellfish from the ocean — shrimp, lobster, crab, oysters, and others — can also be good sources of iodine. As always, I pay attention to where the seafood came from; wild-caught ocean seafood tends to be the better source.

3. Seaweed

Nori, kelp, wakame, and hijiki can contain significant iodine when they're actually grown in the ocean. Coastal cultures like Japan have gotten iodine this way for centuries. Just remember seaweed is the most variable of all — the amount depends heavily on where and how it was grown, and some seaweed contains very large, hard-to-predict amounts.

4. Meat and Organs

Animals need iodine too, so meat can carry it — and organ meats and glandular tissue (like liver and heart) even more so, since animals concentrate iodine in certain tissues. How much depends on what the animal ate and where it was raised, which is one more reason the source and quality of your meat matters.

5. Dairy

Milk, cheese, and other dairy can contain iodine — partly from the cow's own diet, and partly from dairy-farming practices (iodine is sometimes added to feed, and iodine-based sanitizing solutions are used on udders). So dairy can be a source, but once again it depends on the animal and how the dairy was produced.

6. Eggs

Birds need iodine for normal development, and some of it ends up in their eggs. So eggs can contribute iodine to your diet — with the amount depending, as usual, on what the bird ate and where it lived.

7. Coastally Grown Plant Foods

Plants can contain iodine, but only if it's actually present in the soil where they grew. A plant grown in the middle of a continent with little iodine in the soil can't magically create it. Plants grown in coastal regions, where iodine is in the environment, are more likely to contain some.

The Potato Myth

You'll see claims online that potatoes are a great source of iodine. That idea traces back to research on biofortified potatoes — where scientists deliberately put iodine into the soil, grew the potatoes there, and then found iodine in them. All that really proves is that if you concentrate iodine in the soil, the plant takes some up. It doesn't mean an ordinary potato from the store is a reliable iodine source.

Don't Assume Salt Has You Covered

A lot of people assume that because they eat salt, they're getting plenty of iodine. Be careful with that assumption:

• The salt in packaged foods is often not iodized — manufacturers aren't required to use iodized salt, and plain salt can be cheaper.
• Restaurant salt is frequently not iodized either.
• Specialty and rock salts — sea salt, Himalayan, and similar — generally aren't required to contain added iodine, and any natural trace amounts may not be enough to meet your needs.
• Even iodized salt at home only helps if you actually eat enough of it, and its iodine content can fade over time with heat, humidity, light, and air.

If iodine matters to you, read the label instead of guessing — and lean on iodine-containing whole foods that fit your diet.

The Lesson

Iodine is essential, and I'd rather you get it from high-quality real food whenever possible. But don't just look at the name of a food — look at where it came from, where it was grown, and what the animal ate. And remember: the goal is to get enough iodine, not to overdo it.

This article is for general education and is not medical advice. Both too little and too much iodine can affect thyroid function, and needs change during pregnancy and breastfeeding or with a thyroid condition. If you're considering iodine supplementation, talk with a qualified healthcare professional about what's right for you.