Iodine is a non-metallic trace mineral essential for the synthesis of thyroid hormones. In the body, about 70 to 80 per cent of iodine is in the thyroid gland, located in the neck. Iodine deficiency is rare in the United States because the mineral is added to table salt, which is known as iodised salt. Certain signs point to an iodine deficiency, including goitre, weight gain, depression and fatigue. Concentrated food sources with a high iodine content can help supply sufficient iodine to the diet.
When it comes to food, most iodine is found in the ocean. Seaweed, also known as sea vegetables, has a large proportion of iodine and is a primary source of the nutrient. Brown algae has the highest amounts of iodine; the next-highest amounts come from dry brown kelp and dry rockweed, respectively. While red and green algae are lower in iodine, they are high in comparison to foods grown on land. A small amount of seaweed can meet the recommended daily adult requirements for iodine.
Animals known collectively as seafood also absorb a large amount of iodine from the ocean. Shellfish, shrimp and white deepwater fish like cod are all good sources of the mineral. Canned tuna, in oil, also contains a high amount of iodine.
Poultry and Dairy
Among poultry choices, baked turkey breast is the richest in iodine. A large boiled egg, low-fat yoghurt, part-skim mozzarella cheese and 2 per cent cow's milk also contain high levels of iodine.
Iodine exists in soil, but the content may vary because soil erosion can leach away this and other minerals. Beans and seeds highest in iodine content include lima beans, soybeans, cooked navy beans and sesame seeds. Vegetables highest in iodine include spinach, Swiss chard, turnip greens, summer squash and white potatoes with the peel. The herb highest in iodine is garlic.
Strawberries are the fruit richest in iodine. Additionally, bakeries sometimes add iodine to bread dough for its use as a stabilising agent. This additive makes bread an additional rich source of iodine.