What vegetarian foods are high in iodine for thyroid?

November 15, 2025 •

4 min read

According to the National Institutes of Health, the average adult requires 150 micrograms of iodine daily to support healthy thyroid function. For vegetarians, this essential mineral may require special attention, making it crucial to understand what vegetarian foods are high in iodine for thyroid health.

Quick Summary

Maintaining adequate iodine intake is a key consideration for vegetarian diets to support thyroid health. The article details excellent sources, including sea vegetables, dairy products, fortified alternatives, and specific produce, to ensure sufficient iodine.

Key Points

Seaweed is a potent source: Varieties like nori and wakame are excellent plant-based sources, but use high-iodine kelp sparingly to prevent excess intake.
Iodized salt is a simple solution: Using iodized salt for cooking, rather than relying on specialty salts, is an effective way to meet daily needs.
Check fortified food labels: Many plant-based milks and some breads are fortified with iodine; always confirm by reading the product label.
Soil affects plant content: The iodine in land-grown fruits and vegetables, like potatoes and prunes, varies with soil quality, making them a less consistent source than sea vegetables.
Dairy provides iodine: Lacto-ovo vegetarians can obtain significant iodine from milk, yogurt, and eggs, though amounts can vary based on the animals' feed.
Moderate goitrogen intake: Consuming cooked cruciferous vegetables and soy in normal amounts is safe for those with adequate iodine levels and does not pose a threat to thyroid function.

Understanding Iodine's Role in Thyroid Health

Iodine is a trace mineral that plays a vital role in the production of thyroid hormones, specifically triiodothyronine (T3) and thyroxine (T4). These hormones regulate metabolism, growth, and development throughout the body. When iodine intake is insufficient, the thyroid gland may not produce enough hormones, potentially leading to hypothyroidism and an enlarged thyroid, known as a goiter. While many people get iodine from seafood or dairy, vegetarians and vegans must be proactive in their dietary choices to meet the recommended daily intake of 150 mcg for adults.

Top Vegetarian Sources of Iodine

Seaweed and Sea Vegetables

Seaweed is, without a doubt, the most potent plant-based source of iodine. However, the concentration can vary dramatically depending on the species and preparation.

Nori: Often used for sushi wraps, nori has a lower, more consistent iodine content, providing about 16–43 mcg per gram.
Wakame: A brown seaweed common in miso soup, wakame offers a moderate source of iodine, with an average of 66 mcg per gram.
Dulse: This reddish seaweed can be found in flakes and offers a good dose of iodine.
Kelp: Kelp, particularly kombu, is extremely high in iodine, sometimes containing thousands of micrograms per gram. It should be used sparingly and with caution, as excessive intake can also lead to thyroid issues.

Iodized Salt

For many, iodized salt is the simplest and most reliable source of iodine. In the United States, fortification of table salt with iodine began in the 1920s to combat iodine deficiency. A quarter-teaspoon of iodized salt can provide a significant portion of the daily recommended intake. It is important to note that specialty salts, like sea salt or Himalayan pink salt, are not reliably iodized and contain very little iodine. For those watching sodium intake, using iodized salt in moderation during cooking is a practical strategy.

Fortified Foods

Many countries have voluntary fortification programs for certain foods. For vegetarians, this can be a crucial source of iodine.

Fortified Plant-Based Milks: Some manufacturers add potassium iodide to their plant-based milks, such as soy or oat milk. Always check the nutrition label to confirm if iodine has been added, as many brands are not fortified.
Fortified Breads: Some commercial breads use iodate dough conditioners, which contribute to the bread's iodine content. Similar to plant milks, checking the ingredient list is necessary, as this practice is not universal.

Fruits and Vegetables

While the iodine content of fruits and vegetables depends heavily on the soil they are grown in, some produce can contribute to overall intake.

Potatoes: A medium-sized baked potato with the skin on can provide a moderate amount of iodine, especially if the soil is iodine-rich.
Prunes: Dried prunes are a reliable source, with five dried prunes offering about 9% of the daily value.
Cranberries: Cranberries can contain a significant amount of iodine, though it varies based on the soil.
Green Beans and Lima Beans: These beans contain smaller amounts of iodine and are not a primary source, but they contribute to total daily intake.

Dairy and Eggs (for lacto-ovo vegetarians)

Lacto-ovo vegetarians can rely on dairy products and eggs as a key source of iodine. The iodine content in dairy is variable, influenced by the cow's feed and sanitizers used in milking equipment.

Milk: A single cup of cow's milk can provide a substantial amount of iodine.
Yogurt: Plain yogurt is an excellent source, contributing a significant percentage of the daily value per cup.
Eggs: The yolk of one large egg contains a good amount of iodine, making eggs a valuable dietary addition.

Managing Goitrogens in Cruciferous Vegetables

Cruciferous vegetables like broccoli, cauliflower, and kale contain compounds called goitrogens that can interfere with iodine uptake by the thyroid. However, this is typically only a concern in cases of severe iodine deficiency and excessive raw consumption. Cooking these vegetables significantly reduces their goitrogenic effect, and including a wide variety of foods in a balanced diet generally mitigates any risk for those with adequate iodine intake.

Comparison of Vegetarian Iodine Sources


Source	Iodine Content	Considerations for Vegetarians
Seaweed (Nori/Wakame)	High to very high	Excellent plant-based source; be mindful of portion sizes to avoid excessive intake, especially with kelp.
Iodized Table Salt	Reliable, significant	Best used for cooking to control sodium intake; specialty salts are not typically iodized.
Dairy (Milk, Yogurt)	Significant, but variable	Content depends on cattle feed; a strong source for lacto-ovo vegetarians.
Fortified Plant Milk	Variable, needs checking	Not all plant milks are fortified; check the label for potassium iodide.
Eggs (Yolk)	Significant, but variable	Excellent source for lacto-ovo vegetarians, dependent on chicken feed.
Potatoes (with skin)	Small to moderate	Varies by soil iodine content; keeps the skin on for maximum benefit.
Prunes	Moderate	Five dried prunes provide a decent amount; a good snack option.

Conclusion: Strategic Inclusion is Key

For vegetarians, ensuring sufficient iodine for thyroid health involves a strategic approach. Incorporating reliably iodized options like iodized salt, and checking labels for fortified plant milks or breads, provides a solid foundation. For those who consume dairy, milk, yogurt, and eggs are dependable sources. Sea vegetables like nori and wakame offer a potent plant-based boost, but should be consumed in moderation due to variable and sometimes excessive concentrations, particularly with kelp. By diversifying these food sources and being mindful of portion sizes, vegetarians can easily and safely meet their daily iodine requirements. Combining these with other thyroid-supporting nutrients like selenium (found in Brazil nuts) ensures a well-rounded diet for overall health.

For more information on iodine requirements, visit the National Institutes of Health (NIH) Office of Dietary Supplements.(https://ods.od.nih.gov/factsheets/Iodine-Consumer/)

Frequently Asked Questions

The best vegetarian source of iodine is seaweed, with varieties like nori and wakame providing concentrated amounts. However, iodine content can vary, so it's important to consume it in moderation.

Yes, iodized table salt is a very reliable source of iodine and is an easy way to ensure adequate intake, especially if you cook at home. However, be mindful of overall sodium consumption.

A well-planned vegetarian diet that includes reliable sources like iodized salt and fortified foods often provides sufficient iodine. If intake from food is insufficient, a low-dose supplement may be necessary, but it's best to consult a healthcare professional.

Sea vegetables like nori and wakame contain the highest iodine content. Among land-based options, potatoes with the skin and prunes are moderate sources, but their levels can be inconsistent based on the soil.

Yes, cooking cruciferous vegetables like broccoli and kale can significantly reduce their goitrogenic compounds, minimizing any potential interference with iodine absorption.

Yes, it is possible to get too much iodine, especially from overconsuming certain types of seaweed like kelp. Excess iodine can also lead to thyroid dysfunction, so moderation is key.

Many plant-based milks are not fortified with iodine, but some brands do add potassium iodide. It is essential to check the product's nutrition label to see if iodine is listed as an ingredient.