20 Foods High in Iodine: Thyroid, Hormones, and Pregnancy

Iodine is a trace mineral that your thyroid gland depends on completely. Without it, your thyroid cannot produce thyroxine (T4) and triiodothyronine (T3), the two hormones that regulate your metabolic rate, body temperature, heart rate, digestive function, cognitive clarity, and the development of every organ in a growing fetus. Despite being needed in microgram quantities, iodine deficiency remains the most common preventable cause of intellectual disability worldwide and one of the most widespread nutritional deficiencies globally, affecting an estimated two billion people. In developed countries, iodine deficiency is re-emerging as a concern after decades of apparent control, driven by reduced use of iodized salt, increasing popularity of sea salt and specialty salts that are not iodized, and the rise of plant-based diets that exclude the dairy and seafood that provide most dietary iodine. The National Institutes of Health identifies iodine as especially critical for women during pregnancy and breastfeeding, where inadequate intake causes fetal brain damage, cretinism, miscarriage, and stunted growth even when the mother appears clinically normal.

The recommended dietary allowance for iodine is 150 mcg per day for adults, rising to 220 mcg during pregnancy and 290 mcg while breastfeeding, the highest iodine requirement of any life stage. Harvard T.H. Chan School of Public Health notes that iodine is needed to make thyroid hormones that assist with protein synthesis, enzyme activity, and the regulation of normal metabolism, and that without enough iodine these hormones fail to function properly, leading to hypothyroidism, goiter, fatigue, weight gain, hair loss, and in severe cases during development, permanent cognitive impairment. For a broader look at thyroid-supportive nutrition beyond iodine alone, see our guide to foods that are good for thyroid health.

Iodine content in plant foods varies enormously based on soil iodine levels, making seafood and dairy the most reliable consistent sources. The 20 foods below are the richest and most dependable dietary iodine sources available.

Jump to: Seaweed | Cod | Yogurt | Iodized Salt | Shrimp | Milk | Tuna | Oysters | Eggs | Cheddar Cheese | Salmon | Sardines | Cottage Cheese | Scallops | Greek Yogurt | Haddock | Miso | Lima Beans | Fortified Bread | Turkey Breast | FAQ

20 Foods With the Highest Iodine Content

1. Seaweed (Nori, Wakame, Kelp): The Most Iodine-Dense Foods on Earth

Dried seaweed is the most concentrated dietary iodine source available, though content varies enormously by species. One gram of dried kelp can provide anywhere from 16 mcg to over 2,984 mcg of iodine, easily exceeding the tolerable upper intake level of 1,100 mcg in a single small serving. Nori (the thin dried sheets used in sushi rolls) provides approximately 16 to 43 mcg per sheet, making it a moderate and safe everyday iodine source. Wakame provides approximately 66 mcg per gram dried.

Harvard T.H. Chan School of Public Health identifies seaweed as the richest dietary iodine source available but cautions that kelp and other brown seaweeds can contain dangerously excessive iodine that suppresses thyroid function when consumed regularly in large amounts. Nori and wakame are safer everyday choices.

Best eaten: Nori sheets as sushi wrappers or crumbled over rice bowls; wakame in miso soup and seaweed salads; kelp supplements or kelp-heavy preparations should be limited due to excessive iodine risk.

Per 1 nori sheet (2.5 g); kelp provides far more and should be used cautiously.

2. Cod: The Highest Iodine Lean Fish

A 3-ounce serving of cooked cod provides approximately 99 mcg of iodine, two-thirds of the daily requirement in a single lean, mild-flavored fish serving. Cod is one of the most iodine-rich commonly available fish and one of the lowest-calorie high-iodine protein sources, making it an efficient iodine food for people managing calories alongside thyroid health.

The Mayo Clinic identifies fish and seafood as among the most reliable natural iodine sources, noting that ocean fish accumulate iodine from seawater and consistently provide far more iodine than freshwater fish regardless of soil iodine variability that affects plant-based sources.

Best eaten: Baked, grilled, or pan-seared with olive oil and lemon; cod’s mild flavor and firm texture make it one of the most culinarily versatile iodine-rich fish for everyday meals.

Per 3 oz cooked.

3. Plain Low-Fat Yogurt: The Most Accessible Dairy Iodine Source

One cup of plain low-fat yogurt provides approximately 75 mcg of iodine, half the daily requirement in a single cup, alongside calcium, protein, B12, and probiotics. Dairy products are iodine-rich because cows ingest iodine through iodine-supplemented feed and iodine-containing teat dips and sanitizers used in commercial dairy operations, which raise iodine concentrations in milk significantly above what soil iodine alone would produce.

The NIH Office of Dietary Supplements identifies dairy products alongside seafood as the primary iodine contributors in the American diet, with yogurt, milk, and cheese collectively providing the most iodine for most non-seafood eaters.

Best eaten: Plain daily as a breakfast or snack staple; combined with other dairy foods across the day to build cumulative iodine intake reliably.

Per 1 cup plain low-fat yogurt.

4. Iodized Salt: The Most Widely Used Iodine Fortification

One teaspoon of iodized table salt provides approximately 284 mcg of iodine, nearly double the daily requirement in a single teaspoon. Iodized salt has been the primary public health strategy for preventing iodine deficiency since the 1920s and remains the most cost-effective iodine delivery mechanism available globally. One-quarter teaspoon provides approximately 71 mcg of iodine.

The key distinction is iodized versus non-iodized: sea salt, Himalayan pink salt, kosher salt, and most specialty salts are not iodized and provide negligible iodine. As these artisan salts have replaced iodized table salt in many households and restaurants, iodine intake has declined in populations that previously relied on iodized salt as their primary iodine source.

Best eaten: Used in everyday cooking and at the table; one-half teaspoon daily in cooking provides a meaningful iodine contribution; do not rely on sea salt or non-iodized specialty salts as iodine sources.

Per 1 tsp; use iodized table salt specifically, not sea salt or specialty salts.

5. Shrimp: A Low-Calorie Seafood With Strong Iodine Content

A 3-ounce serving of cooked shrimp provides approximately 35 mcg of iodine alongside selenium, complete protein, and choline. Shrimp, like all shellfish and ocean fish, accumulates iodine from seawater reliably regardless of soil iodine variability that affects land-based foods. Its very low calorie content makes it one of the most iodine-efficient foods per calorie available.

Shellfish including shrimp, oysters, and clams are consistently reliable iodine sources because the marine environment provides a steady iodine supply independent of the regional soil variability that makes plant food iodine content so unpredictable.

Best eaten: Steamed, sauteed with garlic and olive oil, or added to grain bowls and salads; combines naturally with other seafood sources across the week for cumulative iodine coverage.

Per 3 oz cooked.

6. Milk (Low-Fat): The Most Universally Consumed Iodine Food

One cup of low-fat milk provides approximately 56 mcg of iodine alongside calcium, vitamin D, B12, and complete protein. For people who drink milk daily, it is one of the most consistent and reliable everyday iodine sources available, particularly in countries like the United States where commercial dairy practices consistently produce iodine-rich milk.

Iodine content in milk varies by season and region: winter milk from housed cattle fed iodine-supplemented feed tends to be higher in iodine than summer milk from pasture-fed cattle. Despite this variability, milk remains one of the most dependable iodine sources for most dairy consumers.

Best eaten: As a standalone drink, in oatmeal, smoothies, and coffee; consistent daily consumption provides reliable iodine alongside calcium and vitamin D.

Per 1 cup (8 oz) low-fat milk.

7. Tuna (Canned): An Affordable Everyday Iodine Fish

A 3-ounce serving of canned light tuna provides approximately 17 mcg of iodine alongside selenium, niacin, and complete protein. While canned tuna is not among the highest-iodine seafood options, its widespread daily consumption as one of the most popular canned proteins makes it a consistent background iodine contributor for millions of households that eat it regularly.

Including canned tuna two to three times per week alongside higher-iodine sources like cod, dairy, and eggs builds cumulative iodine coverage across the week without requiring any single meal to carry the full daily burden.

Best eaten: Mixed with avocado or Greek yogurt, over salads, in whole wheat wraps, or stirred into pasta; choose light tuna for lower mercury compared to albacore.

Per 3 oz canned light tuna in water, drained.

8. Oysters: A Shellfish With Strong Iodine Content

A 3-ounce serving of cooked oysters provides approximately 93 mcg of iodine alongside extraordinary amounts of zinc, selenium, B12, and iron. Oysters are filter feeders that concentrate marine iodine from the seawater they filter, accumulating iodine at levels among the highest of any shellfish alongside their well-documented zinc and mineral density.

Their iodine content adds a thyroid health benefit to the immune-supporting zinc and energy-metabolism selenium that oysters are more commonly recognized for, making them one of the most multi-mineral-targeted shellfish available for comprehensive micronutrient coverage.

Best eaten: Steamed or broiled; raw oysters carry foodborne illness risk for immunocompromised individuals and pregnant women; steamed oysters retain full iodine content.

Per 3 oz cooked.

9. Eggs: A Whole-Food Iodine Source

One large egg provides approximately 26 mcg of iodine, concentrated primarily in the yolk alongside choline, vitamin A, B12, and selenium. Two to three eggs at breakfast contribute 52 to 78 mcg of iodine, a meaningful start toward the daily requirement from a whole food that also provides multiple other critical micronutrients simultaneously.

The iodine content of eggs varies based on the iodine content of the hens’ feed. Eggs from hens fed iodine-supplemented feed provide significantly more iodine than eggs from hens on organic or pasture-based diets without iodine supplementation, making conventional eggs a more reliable iodine source than organic or specialty eggs in some cases.

Best eaten: Scrambled, poached, or hard-boiled; always eat the whole egg including the yolk where all the iodine is concentrated; two to three eggs daily provides a reliable iodine contribution.

Per 1 large conventional egg.

10. Cheddar Cheese: A Dairy Iodine Contributor

One ounce of cheddar cheese provides approximately 12 mcg of iodine alongside calcium, B12, and protein. Hard and aged cheeses generally provide less iodine per ounce than fluid dairy like milk and yogurt because the whey fraction removed during cheesemaking contains a significant portion of the original milk’s iodine content. However, cheese eaten regularly as a daily snack or meal component contributes a consistent background iodine addition.

For people who eat cheese as their primary dairy food rather than drinking milk or eating yogurt, choosing dairy products from multiple categories across the day rather than relying solely on cheese helps maintain more reliable iodine coverage.

Best eaten: Sliced on whole-grain crackers, melted into omelets, or added to grain bowls; consumed alongside milk and yogurt as part of a varied dairy intake for better overall iodine coverage.

Per 1 oz.

11. Salmon (Wild-Caught): A Fatty Fish With Meaningful Iodine

A 3-ounce serving of cooked wild-caught salmon provides approximately 35 mcg of iodine alongside omega-3 fatty acids, vitamin D, B12, and selenium. While salmon is not among the highest-iodine fish, its regular consumption two to three times per week as a primary protein contributes a consistent iodine addition alongside its more widely recognized cardiovascular and brain health benefits.

Wild-caught salmon’s combination of iodine, selenium, and omega-3 fatty acids supports thyroid function through three complementary mechanisms: iodine provides the raw material for thyroid hormone synthesis, selenium drives the deiodinase enzymes that activate T4 into the more potent T3, and omega-3s support the anti-inflammatory environment in which thyroid tissue functions optimally.

Best eaten: Baked, grilled, or pan-seared; wild-caught varieties provide more consistent iodine than farmed salmon fed variable iodine content feeds.

Per 3 oz cooked wild-caught sockeye.

12. Sardines: An Affordable Canned Fish With Iodine

A 3-ounce serving of canned sardines provides approximately 35 mcg of iodine alongside omega-3 fatty acids, calcium from the bones, vitamin D, and B12. Like all ocean fish, sardines accumulate iodine reliably from their marine environment, providing a consistent iodine contribution in an affordable shelf-stable format.

Their combination of iodine, selenium, and omega-3s mirrors the thyroid-supportive nutrient triad found in salmon, making sardines a budget-friendly alternative that delivers comparable thyroid health support at a fraction of the cost.

Best eaten: On whole-grain crackers with lemon and herbs, stirred into pasta, or mashed onto toast; choose bone-in varieties to add calcium alongside their iodine contribution.

Per 3 oz canned in oil, drained.

13. Cottage Cheese: A High-Protein Dairy Iodine Food

One cup of low-fat cottage cheese provides approximately 65 mcg of iodine alongside 25 grams of protein and calcium. Cottage cheese is one of the more iodine-dense dairy foods per serving, providing meaningful iodine in a high-protein, lower-fat format that works well as a daily breakfast or snack staple.

For people who prefer cottage cheese over yogurt as their primary dairy food, it delivers comparable iodine coverage alongside superior protein density, making it one of the most practical dairy iodine sources for people focused on both thyroid health and body composition simultaneously.

Best eaten: As a snack with fruit, as a high-protein bowl topping, stirred into smoothies, or substituted for ricotta in pasta dishes.

Per 1 cup low-fat.

14. Scallops: A Shellfish With High Iodine

A 3-ounce serving of cooked scallops provides approximately 90 mcg of iodine alongside selenium, phosphorus, and complete protein. Scallops are among the most iodine-rich shellfish available and one of the most elegant seafood options for people building iodine intake through dietary variety rather than relying on a single food source.

Their lean, sweet flesh and quick cooking time make scallops a practical special occasion seafood that delivers near-full daily iodine coverage in a single serving alongside their broad mineral profile.

Best eaten: Pan-seared in a very hot pan for two minutes per side until golden, or broiled; pairs with a squeeze of lemon and light herb butter; do not overcook as they become rubbery quickly.

Per 3 oz cooked.

15. Greek Yogurt: A Concentrated Dairy Iodine Source

One cup of plain low-fat Greek yogurt provides approximately 116 mcg of iodine, more than three-quarters of the daily requirement, making it one of the most iodine-dense dairy foods per cup despite its straining process removing some of the liquid whey. Greek yogurt’s higher protein concentration relative to regular yogurt does not reduce its iodine content significantly, and its thickness and satiety make it an ideal daily iodine vehicle for people who eat it consistently.

The American Thyroid Association recommends dairy products including yogurt as reliable everyday iodine sources for women, particularly during pregnancy when iodine requirements nearly double and thyroid hormone production must increase by 50 percent to support fetal development.

Best eaten: Plain with fruit and seeds daily; used as a smoothie base; the higher iodine content versus regular yogurt makes it the preferable dairy choice for people specifically managing thyroid health through diet.

Per 1 cup plain low-fat Greek yogurt.

16. Haddock: A White Fish With Exceptional Iodine

A 3-ounce serving of cooked haddock provides approximately 104 mcg of iodine, nearly the full daily requirement in a single lean serving. Haddock is among the most iodine-rich white fish available and is widely consumed across the United Kingdom and North America where it is a staple in fish and chips and everyday fish dishes.

Its exceptionally high iodine content relative to its low calorie and fat content makes haddock one of the most iodine-efficient foods available by calorie, delivering near-complete daily coverage in a 90-calorie serving of mild, versatile white fish.

Best eaten: Baked, grilled, or poached; its mild flavor and firm texture make it suitable for a wide range of preparations from simple baking to breaded dishes; pairs well with lemon, dill, and light sauces.

Per 3 oz cooked.

17. Miso: A Fermented Soy Condiment With Iodine From Sea Salt

One tablespoon of miso paste provides approximately 18 mcg of iodine, derived primarily from the sea salt or iodized salt used in its production alongside trace amounts from seaweed when included. While miso is not primarily known as an iodine food, its regular daily use as a soup base and condiment in Japanese-inspired eating patterns contributes a consistent small iodine addition that compounds meaningfully over the course of a week.

Miso made with iodized salt provides more iodine than miso made with non-iodized sea salt, and seaweed-containing miso varieties provide higher concentrations still. Checking ingredient labels helps identify the more iodine-dense miso varieties for daily use.

Best eaten: Dissolved into warm broth for miso soup, used as a marinade base, stirred into dressings; never boil miso as high heat destroys its live probiotic cultures alongside some iodine content.

Per 1 tbsp; varies by salt type used in production.

18. Lima Beans: A Plant Food With Surprising Iodine

One cup of cooked lima beans provides approximately 16 mcg of iodine alongside protein, fiber, folate, iron, and magnesium. Lima beans are one of the more iodine-rich common legumes, though plant food iodine content varies significantly based on soil iodine levels and irrigation water sources. They represent one of the more reliable plant-based iodine options among legumes.

For vegetarians and vegans who do not consume dairy or seafood, legumes including lima beans and navy beans contribute modest but real iodine alongside their broad mineral and fiber content, forming part of a plant-based iodine strategy that also relies heavily on iodized salt and fortified foods. A full vegan diet foods grocery list can help round out the rest of a plant-based plate while iodine is covered through salt and fortified foods.

Best eaten: In soups and stews, mashed as a creamy dip with herbs and lemon, or served as a side dish seasoned with garlic and olive oil.

Per 1 cup cooked; varies by soil iodine content.

19. Fortified Bread (Made With Iodized Salt): An Everyday Grain Source

Two slices of commercially produced bread made with iodized salt provide approximately 45 mcg of iodine, a meaningful contribution from a staple food most people eat daily. Commercial bread production uses large quantities of salt, and when that salt is iodized, bread becomes a significant background iodine contributor across the population.

The key variable is whether the bread’s salt is iodized: artisan sourdoughs, specialty breads made with sea salt, and imported breads may use non-iodized salt and provide negligible iodine. Standard commercially produced sandwich bread made with iodized salt is a reliable everyday iodine source.

Best eaten: As everyday sandwich bread and toast; choose standard commercially produced varieties made with iodized salt rather than artisan breads made with sea salt for reliable iodine contribution.

Per 2 slices; iodine content depends on whether iodized salt was used in production.

20. Turkey Breast: A Lean Meat With Modest Iodine

A 3-ounce serving of cooked turkey breast provides approximately 34 mcg of iodine alongside 26 grams of protein, selenium, zinc, and B vitamins. Poultry including turkey and chicken contains iodine from iodine-supplemented feed used in commercial production, making conventionally raised poultry a more consistent iodine source than pasture-raised or organic poultry that may receive less iodine supplementation.

Turkey’s selenium content complements its iodine contribution for thyroid health: selenium is required to convert T4 to the more metabolically active T3, meaning adequate selenium ensures that the iodine used to produce T4 is efficiently activated into the usable thyroid hormone form.

Best eaten: Roasted, sliced thin for sandwiches, or cubed into grain bowls; avoid heavily processed deli turkey high in added sodium.

Per 3 oz cooked.

Summary: Top 20 Iodine Foods at a Glance

Tips for Meeting Your Daily Iodine Requirement

Switch to iodized salt for all home cooking. This is the single most impactful iodine habit for most households. One-quarter to one-half teaspoon of iodized salt used daily in cooking provides 71 to 142 mcg of iodine, covering half to nearly all of the daily requirement before any other food contributes. Sea salt, Himalayan pink salt, and kosher salt are not iodized and provide negligible iodine regardless of how much you use.

Eat dairy foods consistently. Yogurt, milk, and cottage cheese are the most reliable everyday iodine sources for most people who do not eat fish daily. A cup of Greek yogurt at breakfast plus a glass of milk at any meal provides approximately 170 mcg of iodine, exceeding the full daily requirement before any other food contributes.

Pregnant and breastfeeding women must prioritize iodine intentionally. The iodine requirement during pregnancy is 220 mcg per day and rises to 290 mcg while breastfeeding, yet most prenatal vitamins contain only 150 to 220 mcg of iodine and some contain none at all. Prenatal supplements alone often fall short on iodine, so pregnant and breastfeeding women should pair a prenatal supplement with iodine-rich foods from diet as well; a full pregnancy diet grocery list by trimester can help with planning. Adequate iodine intake during pregnancy is non-negotiable for fetal brain development.

Vegans and dairy-free eaters need a careful iodine strategy. Removing dairy and seafood from the diet eliminates the two most reliable everyday iodine sources. Vegans must rely on iodized salt, fortified plant milks, nori and moderate seaweed consumption, and iodine supplements to meet requirements reliably. Sea vegetables other than nori carry iodine excess risk and should not be used as a primary daily source.

Selenium supports iodine in thyroid function. Selenium is required for the deiodinase enzymes that convert T4 to the more potent T3, the active thyroid hormone. Without adequate selenium, normal iodine intake does not translate to normal thyroid hormone activity. Eating selenium-rich foods including Brazil nuts (one per day), fish, eggs, and lean meats alongside iodine-rich foods ensures the full thyroid hormone production pathway is supported.

Excessive iodine is also harmful. The tolerable upper intake level for iodine is 1,100 mcg per day for adults. Both deficiency and excess can cause thyroid dysfunction: very high iodine intake from aggressive seaweed consumption, high-dose supplements, or iodine-containing medications can trigger hypothyroidism or hyperthyroidism in susceptible individuals. Kelp tablets, kelp powder, and bladder wrack supplements are high-risk iodine sources that can easily exceed safe limits in small doses.

Frequently Asked Questions

Does sea salt contain iodine like table salt?
No. Only salt specifically labeled “iodized” has iodine added to it. Sea salt, kosher salt, Himalayan pink salt, and other specialty salts are not fortified with iodine unless the label says so, which is one of the main reasons iodine deficiency is re-emerging as more households switch away from plain iodized table salt.

How much iodine do I need per day?
Most adults need 150 mcg per day. That requirement rises to 220 mcg during pregnancy and 290 mcg while breastfeeding, the highest iodine requirement of any life stage, since the developing fetus and nursing infant depend entirely on the mother’s iodine intake for their own thyroid hormone production.

Can iodine deficiency cause weight gain?
Yes, indirectly. Iodine is required to produce thyroid hormones that regulate metabolic rate, and a significant deficiency can lead to hypothyroidism, which slows metabolism and is commonly associated with unexplained weight gain, fatigue, and cold intolerance. Correcting a deficiency through diet or supplementation typically resolves the metabolic slowdown, though it will not reverse weight gain from other causes.

Do vegans need an iodine supplement?
Many do. Since dairy and seafood provide most dietary iodine, vegans who rely only on iodized salt and fortified foods can fall short, especially if they use unfortified specialty salts or avoid processed bread. Seaweed is an option, but its iodine content is highly variable and can easily overshoot the safe upper limit, so a measured supplement or regular use of iodized salt is often the more reliable approach.

Can you get too much iodine from food alone?
It’s uncommon from ordinary foods, but not impossible. The tolerable upper intake level for adults is 1,100 mcg per day, and a single small serving of iodine-dense kelp can exceed that on its own. Routine seafood, dairy, and iodized salt intake rarely comes close to this limit, but regular kelp or seaweed supplement use is the most common way people accidentally overshoot it.

The Bottom Line

Iodine is a mineral whose importance is concentrated in a very specific biological function: making thyroid hormones that govern your metabolism, energy levels, cognitive clarity, and fetal brain development. For most people, meeting the daily requirement is straightforward through a diet that includes dairy foods daily, seafood two to three times per week, and iodized salt in cooking. The critical gaps are in populations abandoning iodized salt, adopting dairy-free or vegan diets without iodine planning, and pregnant women whose sharply elevated requirements may not be met by standard prenatal vitamins alone. Thyroid health, hormonal balance, and fetal cognitive development all depend on a mineral that is simple to obtain through food once you know which foods reliably provide it.

Nutrition data sourced from the USDA FoodData Central database. Iodine content in plant foods varies significantly based on soil iodine levels. This article is for informational purposes only and does not constitute medical advice. People with thyroid conditions including Hashimoto’s thyroiditis, Graves’ disease, or thyroid nodules should consult their endocrinologist before significantly increasing iodine intake, as both excess and deficiency can worsen thyroid disorders in susceptible individuals.

Save It For Later