Iodine is a nutrient that keeps the thyroid healthy and helps this important gland produce the correct amount of thyroid hormones. Because several commercial food products are enriched with this mineral, most people get enough iodine in their daily diets. However, if you're concerned about your iodine intake, you can choose from a number foods that are rich in iodine.
Today, most people get plenty of iodine in their diets because the mineral is added to salt. This is why most commercial table salt is labeled as "iodized." Before the practice of adding iodine to salt was adopted in the 1920s, however, people in parts of the United States developed goiters and thyroid problems due to lack of iodine in the diet. Since the late 20th century, however, sea salt has become more widely available as a culinary alternative to table salt. While sea salt has many advantages, it contains much lower concentrations of iodine than traditionally manufactured table salt.
Kelp, a type of algae that grows in saltwater oceans, is high in iodine. A serving of kelp contains just nine calories but provides more than twice the recommended daily allowance, or RDA, of iodine. Kelp is used in some Asian cuisines and can be processed to produce thickeners used in packaged food.
Dairy products, particularly yogurt, are rich in iodine. A serving of low-fat yogurt contains more than 50 percent of your RDA of iodine, while a serving of 2 percent milk contains almost 40 percent of your RDA of this mineral. Cheese can also be a significant source of the nutrient, providing 7 or 8 percent of the RDA.
Saltwater fish tends to be high in iodine because its habitat contains this nutrient, and many fish concentrate iodine in their bodies' tissues. Seafood varieties that are particularly rich in iodine include sea bass, haddock, cod and perch. A three-ounce serving of cod has about 66 percent of the RDA for iodine.
Some parts of the country have very low concentrations of iodine in the soil, which could lead to iodine deficiency in the absences of nutritional supplements. This is particularly true of soil at high elevations or soil in parts of the country far from seacoasts. Other parts of the country, however, have iodine-rich soil, and fruits and vegetables grown in this soil will have higher concentrations of iodine. Strawberries, in particular, are a good source of iodine, containing about 7 or 8 percent of the RDA in each serving.