Plenty of everyday foods contain iodine naturally, no salt shaker required. Dairy, seafood, eggs, and seaweed are the richest sources, while most fruits, vegetables, and grains contribute very little. Adults need about 150 micrograms (mcg) of iodine per day, and a single cup of milk or a serving of cod can get you more than halfway there.
Dairy Is a Top Source Most People Overlook
Cow’s milk is one of the most reliable iodine sources in the Western diet, and most people have no idea. A cup of nonfat milk averages about 84 mcg of iodine, though individual samples range from 38 to 160 mcg per cup depending on the brand and what the cows were fed. Whole, 2%, and 1% milk all deliver similar amounts, roughly 34 to 37 mcg per 100 grams.
Greek yogurt is even more concentrated. A three-quarter cup serving of plain nonfat Greek yogurt provides around 87 mcg, which covers more than half the daily target on its own. Flavored yogurts and frozen yogurt still contain meaningful amounts, generally in the 32 to 44 mcg per 100 grams range. Cheese contributes some iodine too, though less predictably than milk or yogurt.
If you drink plant-based milk alternatives, check the label carefully. In a UK market survey, only 20% of plant-based milk alternatives were fortified with iodine, compared to 88% fortified with calcium. Plant-based yogurt alternatives fared even worse, with just 6% containing added iodine. Unfortified plant milks provide less than 5 mcg per serving, which is essentially negligible.
Seafood Varies Wildly by Species
Not all seafood is created equal when it comes to iodine. Cod and lobster are standouts: a 3-ounce serving of baked cod delivers 146 mcg, and the same amount of cooked lobster provides 157 mcg. Either one nearly covers your entire day’s needs in a single serving.
Other shellfish fall in a solid middle range. Wild oysters provide about 93 mcg per 3-ounce serving, while canned clams and frozen fish sticks each offer around 56 to 57 mcg. Canned blue crab comes in at 32 mcg.
Many popular fish, however, are surprisingly low. Baked salmon provides just 11 mcg per serving. Canned tuna in water has only 8 mcg. Tilapia delivers about 6 mcg, and catfish is nearly negligible at under 3 mcg. If you’re eating fish specifically for iodine, the type you choose matters enormously. Cod and lobster deliver 10 to 15 times more iodine per serving than salmon or tuna.
Eggs Pack a Solid Dose
One large hard-boiled egg contains about 31 mcg of iodine, roughly 20% of the daily recommendation. Two eggs at breakfast gets you to 40% before you’ve left the house. Scrambled eggs retain most of their iodine as well, at around 43 mcg per 100 grams. The iodine in eggs comes primarily from the yolk, so egg white-only dishes won’t give you the same benefit.
Seaweed: Powerful but Easy to Overdo
Seaweed contains more iodine per gram than any other food, but the range between species is enormous. Nori, the type wrapped around sushi rolls, is relatively mild at about 18 mcg per gram. Two sheets of nori provide roughly 37 mcg, a reasonable and safe amount. Wakame, commonly found in miso soup, jumps to about 172 mcg per gram.
Kelp varieties are in a different league entirely. Kombu averages 2,267 mcg per gram, sugar kelp around 4,400 mcg per gram, and oarweed tops the chart at 7,800 mcg per gram. A single gram of kombu, a piece roughly the size of a postage stamp, delivers more than 15 times the daily recommendation. The tolerable upper limit for adults is 1,100 mcg per day, so even small amounts of kelp can push you well past that threshold.
Nori and dulse are the safest seaweeds for regular consumption. If you enjoy kelp or kombu, use them sparingly, as a seasoning rather than a serving.
Plant Foods Are Mostly Unreliable
If you’re hoping to get iodine from fruits, vegetables, or legumes, the numbers are discouraging. Potatoes contain approximately 1 mcg per 100 grams. Strawberries provide about the same. A full 400-gram can of kidney beans offers roughly 12 mcg, which is less than 10% of daily needs. Ten dried prunes contribute just 2 mcg. A standard 80-gram portion of most fruits or vegetables provides around 3 mcg.
Two slices of white or brown bread deliver about 10 mcg, partly because some commercial breads use iodine-containing dough conditioners. Nuts provide around 5 mcg per 25-gram handful. These amounts add up slowly over a full day of eating, but no single plant food comes close to what a glass of milk or a serving of fish provides.
The iodine content of produce also depends heavily on geography. Iodine exists naturally in soil, but concentrations vary by region. Crops grown in mountainous areas or regions far from the coast tend to have lower iodine levels. This means the same vegetable can contain different amounts of iodine depending on where it was farmed.
Who Needs to Pay Extra Attention
Most adults need 150 mcg of iodine daily. That number rises to 220 mcg during pregnancy and 290 mcg while breastfeeding, because iodine is critical for fetal and infant brain development.
Vegans face the steepest challenge. Without dairy, eggs, or seafood, the richest natural sources are off the table. And since most plant-based alternatives aren’t fortified with iodine, switching from cow’s milk to oat or almond milk can quietly eliminate a major source from your diet. Nori is one of the few vegan-friendly options with meaningful iodine content, and a supplement containing iodine is worth considering if your diet is entirely plant-based.
People who avoid iodized salt, whether by choice or because they use sea salt, kosher salt, or pink Himalayan salt, should also be aware that these alternatives typically contain little to no iodine. Making sure your diet includes regular servings of dairy, eggs, or seafood becomes more important if your salt doesn’t fill the gap.
Quick Comparison by Serving
- Lobster (3 oz): 157 mcg
- Cod (3 oz): 146 mcg
- Oysters (3 oz): 93 mcg
- Greek yogurt, plain (¾ cup): 87 mcg
- Milk (1 cup): 84 mcg
- Canned clams (3 oz): 56 mcg
- Nori (2 sheets): 37 mcg
- Egg, hard-boiled (1 large): 31 mcg
- Canned tuna (3 oz): 8 mcg
- Bread (2 slices): 10 mcg
- Kidney beans (1 can): 12 mcg