The Undisputed Top Vegetable for Iodine: Seaweed
For anyone looking to obtain a significant amount of iodine from a vegetable source, seaweed stands in a league of its own. It's the undisputed champion due to its unique ability to absorb and concentrate minerals directly from the ocean. Different types of seaweed offer varying levels of iodine, but generally, brown seaweeds contain more than red or green varieties.
Kelp: The Ultimate Iodine Powerhouse
Among all seaweeds, kelp is the most famous for its extraordinarily high iodine content. Varieties like kombu can contain staggering amounts, so much so that excessive consumption should be avoided to prevent over-intake. Kelp is often used in dried form to make broth or as a supplement, but it's important to use it sparingly.
Other Notable Seaweed Varieties
Besides kelp, other seaweeds are excellent sources of iodine, though with lower, more manageable levels. Wakame, commonly found in miso soup, offers a moderate amount of iodine, with variations depending on where it was grown. Nori, the classic seaweed used for sushi rolls, also contains a reliable amount of the mineral. Dulse, a red seaweed, provides another solid option for those seeking iodine from the sea.
Land-Based Vegetables with Iodine
While seaweed provides the most concentrated sources, certain land-based vegetables can also contribute to your iodine intake. However, their iodine content is highly variable and depends heavily on the mineral content of the soil they were grown in.
Potatoes
An organic potato, especially eaten with the skin on, can contain a decent amount of iodine. The mineral is present in the soil and absorbed by the plant, so potatoes grown in iodine-rich soil will be better sources.
Lima Beans and Green Beans
Legumes such as lima beans and green beans can also be a source of iodine. One cup of cooked lima beans can provide a measurable amount, and green beans are also noted for their iodine content.
Spinach and Other Leafy Greens
Leafy greens like spinach, watercress, and spring greens contain some iodine. Again, the mineral content of the soil is the main determinant of how much iodine these vegetables will ultimately contain.
Fortified and Other Sources
For those who don't regularly consume seaweed, other plant-based and fortified options can help. Iodized table salt is a primary source of iodine for many people. Some breads in certain regions are also made with iodized salt.
Comparison of Iodine Sources
| Source | Serving Size | Approximate Iodine (mcg) | Notes |
|---|---|---|---|
| Kombu Kelp (Dried) | 1 gram | Up to 2,984 | Extremely high, use with caution |
| Wakame Seaweed | 1 gram | Around 66 | Moderate content, varies by region |
| Nori Seaweed | 1 sheet | 16-43 | Found in sushi rolls |
| Potato (with skin) | 1 medium | ~52 | Content varies based on soil |
| Lima Beans (cooked) | ½ cup | ~8 | Varies with soil conditions |
| Green Peas (cooked) | ½ cup | ~4 | Generally lower content |
Cooking and Preparation
It is important to note that cooking methods can affect iodine levels. Boiling vegetables can cause some of the mineral to leach into the cooking water. Steaming or baking can help retain more nutrients. For seaweed, a small amount goes a long way, so it's best to start with minimal amounts and use it as a flavorful seasoning.
Conclusion: Seaweed is the Key for High Iodine
When asking "Which vegetable has a lot of iodine in it?" the definitive answer is seaweed. For those seeking the most potent plant-based source, kelp is the leader, but other seaweeds like wakame and nori are also excellent options. While land-based vegetables like potatoes and lima beans contain some iodine, their levels are inconsistent and dependent on soil quality. For a reliable intake on a plant-based diet, incorporating moderate amounts of seaweed or using iodized salt is a safe and effective strategy.
