What is the best way to consume iodine?

January 11, 2026 •

4 min read

Globally, nearly one-third of the population is still at risk for iodine deficiency, highlighting the importance of consuming this essential mineral correctly. Finding the optimal approach requires understanding the best sources and how they fit into a balanced diet, so what is the best way to consume iodine?

Quick Summary

The optimal approach to consuming iodine involves a balanced diet rich in seafood, dairy, and eggs, supplemented by using iodized salt. Supplements may be necessary for pregnant women or those with dietary restrictions like vegans.

Key Points

Rely on Whole Foods First: The most balanced way to consume iodine is by including foods like seaweed, fish, dairy, and eggs in your regular diet.
Choose Iodized Salt: Opt for iodized table salt over non-iodized alternatives, as it's a simple, effective, and regulated source of iodine.
Supplement with Caution: Only use iodine supplements if you are in an at-risk group (e.g., pregnant or vegan), and choose standardized formulas over kelp products, which have unpredictable iodine content.
Be Aware of Excess: Excessive iodine intake can cause thyroid problems, including goiter, just like deficiency can. Monitor your intake from all sources and stay within the safe upper limit.
Check Product Labels: Don't assume all processed foods or salts contain iodine. Read labels for 'iodized' salt and check ingredient lists for fortified breads.
Consult a Doctor: If you have a pre-existing thyroid condition or are considering a supplement, seek professional medical advice to tailor your iodine strategy safely.

Why Iodine is a Crucial Nutrient

Iodine is a vital trace mineral that the body cannot produce on its own. It is an essential component of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3), which regulate key bodily functions, including metabolism, growth, and development. Without enough iodine, the thyroid cannot produce sufficient hormones, leading to complications like goiter and hypothyroidism. This is why selecting the right method for iodine consumption is critical for overall health.

The Primary Dietary Sources of Iodine

For most people, the best way to consume iodine is through food. Natural sources provide a steady and balanced intake alongside other essential nutrients. The iodine content in soil and water varies globally, impacting the levels in locally grown produce, but marine and dairy products are consistently reliable sources.

Marine Sources

Foods from the sea are naturally rich in iodine because they absorb it from seawater.

Seaweed (Kelp, Nori, Wakame): By far the most potent source, with concentrations that can vary significantly. Some types, like kombu kelp, can provide several hundred percent of the daily value in just a small serving, though this high amount also poses a risk of excess intake.
Fish and Shellfish: Cod, tuna, shrimp, and oysters are excellent sources. Leaner fish tend to have higher iodine levels than fattier varieties.

Dairy Products

Dairy is a major contributor to iodine intake, particularly in countries with fortified animal feed.

Milk: A single cup can provide a substantial portion of the recommended daily intake.
Yogurt and Cheese: These are also good sources, with plain Greek yogurt being particularly rich in iodine.

Other Reliable Food Sources

Eggs: The yolk contains a good amount of iodine, making eggs a versatile dietary option.
Iodized Salt: A simple and effective way to ensure consistent intake, widely used in salt fortification programs. However, be aware that processed foods often use non-iodized salt.
Certain Baked Goods: Some breads are fortified with iodate dough conditioners, but this practice is not universal, and labeling should be checked.

Iodine Supplements: When and How to Use Them

Dietary supplements can be a necessary alternative for specific populations or for individuals with inadequate dietary intake. The iodine in supplements is typically in the form of potassium iodide or sodium iodide.

Consider supplements if you:

Are pregnant or breastfeeding, as requirements increase significantly during these stages.
Follow a vegan diet and do not consume dairy, eggs, or marine products.
Live in a region with low iodine soil and do not consume fortified products.

Crucial Caveat for Kelp Supplements: The iodine content in kelp supplements is highly variable and can easily exceed the safe upper intake level. For this reason, the British Dietetic Association (BDA) advises against using them as an iodine source. Stick to multivitamin/mineral supplements with standardized iodine content (e.g., 150 mcg) or targeted iodine-only supplements after consulting a healthcare professional.

Food vs. Supplement: A Comparison


Feature	Dietary Sources (Food)	Supplements (e.g., Multivitamin)
Completeness	Provides iodine alongside other natural nutrients, vitamins, and minerals.	Isolated nutrient; doesn't offer additional benefits from whole foods.
Dosage Control	Iodine content varies naturally based on food source, origin, and preparation.	Precise dosage is listed on the label, offering better control.
Risk of Excess	High intake is possible, especially with large amounts of certain seaweed, but less common with a balanced diet.	Can be a higher risk if multiple high-dose supplements are taken or kelp products are used.
Best For	The general population aiming for daily needs via a balanced, whole-food diet.	Pregnant/breastfeeding women and individuals with dietary restrictions or clinically diagnosed deficiency.
Interaction	Generally safe; few interactions unless consuming goitrogenic foods in large quantities with existing deficiency.	Can interact with certain medications, such as ACE inhibitors and diuretics; consult a doctor.

Potential Health Concerns with Excessive Iodine

While rare, consuming too much iodine can cause adverse effects, particularly in sensitive individuals or those with pre-existing thyroid conditions. Similar to deficiency, iodine excess can cause or worsen a goiter, leading to thyroid inflammation or dysfunction. The Tolerable Upper Intake Level for adults is 1,100 mcg per day. It is crucial to stay below this level from all sources combined unless advised by a healthcare provider for medical reasons.

Conclusion: Finding the Right Balance

The best way to consume iodine for most healthy adults is through a balanced diet incorporating iodine-rich foods like seafood and dairy, and using iodized salt for cooking. Seaweed is a potent source but should be consumed cautiously due to its highly variable and often concentrated iodine levels. For at-risk groups, such as pregnant women or vegans, a standardized supplement is a reliable and safe option, as recommended by health bodies like the American Thyroid Association. Always consult a healthcare professional before starting new supplements, especially if you have an existing thyroid condition, to determine the most appropriate approach for your individual needs. By focusing on quality food sources and strategic supplementation where necessary, you can ensure your body receives the optimal amount of iodine to support a healthy thyroid and overall well-being.

For more information on iodine requirements and sources, you can visit the NIH Office of Dietary Supplements website.

Frequently Asked Questions

Some of the best food sources of iodine include seaweed (especially kelp and nori), seafood like cod, tuna, and shrimp, dairy products such as milk and yogurt, and eggs.

No. Iodized salt is table salt that has had iodine added to it for fortification. Sea salt is not a reliable source of iodine and often contains negligible amounts.

The recommended daily intake for most adults is 150 micrograms (mcg) per day. Pregnant and breastfeeding women have higher requirements.

It can be difficult to get sufficient iodine from a strict vegan diet. Vegans may need to consume fortified plant-based milk alternatives or consider a supplement under a doctor's guidance.

For most people, meeting iodine recommendations through a balanced diet is preferred. Supplements are primarily recommended for individuals with specific needs, such as pregnant women or those with dietary restrictions.

Excessive iodine can cause thyroid gland inflammation and dysfunction, leading to conditions like goiter. The tolerable upper intake level for adults is 1,100 mcg per day to avoid adverse effects.

The amount of iodine in seaweed can vary widely depending on the species, the region it was grown, and its preparation. Some kelp varieties contain extremely high levels, making it easy to exceed the safe intake limit.