Foods that are high in iodine include seafood such as sea vegetables, oysters, shrimp and finfish, as well as salt that's fortified with iodine. Dairy products such as milk, yogurt and cheese also have some iodine, and it's commonly found in plants that have been grown in iodine-rich soil. Iodine is an element that's necessary to keep the thyroid hormones in balance.
Sea vegetables such as kelp and wakame contain up to 500 percent of the daily value, or DV, of iodine. This makes sea vegetables far and away some of the best sources of iodine. The next best source, according to The World's Healthiest Foods, is the scallop, a shellfish which contains 90 percent of the DV of iodine. It's followed by cod, yogurt, shrimp, sardines, salmon, cow's milk, eggs and tuna. The recommended DV of iodine is 150 micrograms per day.
Though iodine is necessary for health, it can also cause problems if it's taken in excess. Too much can cause an inflammation of the salivary glands, nausea and vomiting, and other oral problems. Iodine should also be avoided if the person has an elevated potassium level.
There are also some foods that inhibit the absorption of iodine. These include cruciferous vegetables such as cabbage, Brussels sprouts and cauliflower. Rutabagas are also iodine antagonists.