What Veggies Have High Iodine Content?

December 13, 2025 •

3 min read

According to the National Institutes of Health, most fruits and vegetables are generally poor sources of iodine, with the most concentrated vegetable sources being those from the sea. This guide explores exactly what veggies have high iodine, detailing both marine and land-based options to help you meet your nutritional needs.

Quick Summary

The highest iodine content in vegetables is found in seaweeds like kelp, nori, and wakame due to their marine environment. Some land-based vegetables, such as potatoes and lima beans, also contain notable amounts, although levels can vary significantly depending on the soil composition where they are grown.

Key Points

Sea vegetables are the best source: Seaweeds like kelp, nori, and wakame are exceptionally high in iodine due to absorbing minerals from the ocean.
Iodine levels vary in land vegetables: The mineral content of land-based vegetables, such as potatoes, spinach, and lima beans, depends largely on the soil in which they were grown.
Kelp is extremely potent: Kelp (kombu) provides an extremely high concentration of iodine and should be consumed in moderation to avoid excessive intake.
Incorporate seaweeds for a reliable source: To ensure sufficient iodine on a plant-based diet, incorporate various types of sea vegetables into your meals.
Consider iodized salt: Using iodized table salt is a simple, effective way to supplement iodine intake, especially if relying on land vegetables.
Cruciferous vegetables can interfere: For individuals with marginal iodine status, large amounts of raw cruciferous vegetables like cabbage can affect iodine uptake, although this is not typically an issue for those with adequate intake.
Check your sources: Iodine content can vary significantly, so it's wise to rely on a mix of reliable sources rather than a single type of food.

Sea vegetables: The powerhouse of iodine

When considering which vegetables have the highest iodine content, sea vegetables, or seaweeds, are the undisputed champions. Their unique ability to absorb the mineral-rich properties of the ocean makes them a superfood for iodine intake. The amount of iodine can vary widely by species, growing location, and season, but their concentration is consistently high compared to land-based plants.

Types of sea vegetables rich in iodine

Kelp: Often cited as the richest source, certain kelp species like kombu can contain an exceptionally high amount of iodine, sometimes providing nearly 2,000% of the daily value in just one gram. It is important to consume kelp in moderation due to its potency.
Nori: This red seaweed, famously used to wrap sushi rolls, offers a more moderate but still significant dose of iodine. A few grams can provide a substantial portion of the recommended daily intake.
Wakame: With a slightly sweet flavor, wakame is a popular addition to miso soup and salads. Its iodine content can vary based on origin but is consistently a strong source.
Dulse: This red seaweed is a great option for a flavor boost, especially in flake form, offering a good amount of iodine.

Land vegetables that contain iodine

While sea vegetables provide the most concentrated doses, several land vegetables can contribute to your overall iodine intake, though the amounts are generally much lower and can fluctuate. The iodine levels in these plants are directly influenced by the soil's mineral content.

How soil impacts iodine content

In many regions, especially mountainous areas and certain river valleys, the soil is naturally iodine-deficient. This means crops grown in these areas will contain less of the mineral. In contrast, crops grown in iodine-rich soils will have a higher content. Here are some of the most notable land vegetables containing iodine:

Potatoes: Particularly when baked with the skin on, a single medium-sized potato can contain a useful amount of iodine.
Lima Beans: Cooked lima beans are a decent plant-based source of iodine, contributing a moderate amount per cup.
Spinach: Fresh or baby spinach is a leafy green that, depending on soil, can offer a small but helpful amount of iodine.
Corn: Both fresh and canned corn can provide a minimal amount of this essential mineral.
Green Beans: These common vegetables add a small quantity of iodine to your diet.

Comparison of iodine in vegetables

To illustrate the significant difference in iodine concentration, the following table compares common sea and land vegetables. Values are approximate and depend heavily on growing conditions and preparation.


Vegetable	Typical Serving Size	Estimated Iodine (mcg) per Serving
Kelp (dried)	1 gram	Up to 2,984
Nori (dried)	5 grams (approx. 2 tbsp flakes)	116
Wakame (dried)	1 gram	66 (average)
Potato (with skin, cooked)	1 medium	52
Lima Beans (cooked)	½ cup	8
Corn (cooked)	½ cup	7
Spinach (boiled)	½ cup	2

Maximizing iodine intake from plant-based sources

For those following a plant-based diet, it is important to incorporate iodine strategically to ensure adequate intake. Including sea vegetables is the most direct and effective strategy. However, relying solely on land vegetables can be less reliable due to inconsistent soil content. The use of iodized salt in cooking is a common and affordable way to supplement intake. Combining these approaches offers a well-rounded strategy for meeting your daily requirements.

It is also worth noting that some cruciferous vegetables, such as broccoli and cabbage, contain compounds called goitrogens, which can interfere with iodine absorption. For individuals with a marginal iodine status, excessive consumption of these raw vegetables could potentially be an issue, although this is generally not a concern for most people with adequate iodine intake.

Conclusion

While iodine is a crucial mineral for thyroid function, its presence in land vegetables is minimal and highly variable based on soil conditions. The most reliable and concentrated vegetable sources are marine-based, with kelp, nori, and wakame topping the list. For those looking to increase their iodine through a plant-based diet, incorporating sea vegetables is the most effective method, complemented by the use of iodized salt. Always consult a healthcare provider or a registered dietitian if you have concerns about your iodine intake, especially if you have an underlying thyroid condition. For more information on the health impacts of iodine, refer to the National Institutes of Health Office of Dietary Supplements fact sheet on iodine.(https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/)

Frequently Asked Questions

Dried kelp, especially kombu, is consistently cited as having the highest iodine content among all food sources, including seaweeds.

It is difficult to get a reliable, consistent amount of iodine from land vegetables alone, as their content is highly variable and often low. Sea vegetables and iodized salt are more dependable sources.

While it's rare to consume too much iodine from a balanced diet, the extreme concentration in some seaweeds like kelp means overconsumption is possible. Excessive intake can lead to thyroid dysfunction in susceptible individuals, so moderation is key.

No, most leafy greens are poor sources of iodine. Spinach may contain some, but its content is dependent on the soil. Sea vegetables are the main leafy source of significant iodine.

The effect of cooking on iodine content can vary. Some research suggests heating can decrease iodine levels in seaweeds, but more study is needed. In general, the mineral content of vegetables can be affected by cooking methods.

The potato, particularly when eaten with the skin, is a surprising source of iodine, with a single medium-sized potato potentially providing a notable amount.

While many types of beans contain some iodine, the amount is often relatively low. Lima beans are one variety noted for having a moderate iodine content.