What is a low-iodine diet?

A low-iodine diet lowers the amount of iodine in your body. You'll avoid foods that contain a lot of iodine. These include iodized salt, seafood, dairy foods, and many processed foods. A low-iodine diet isn't the same as a low-salt diet.

Why is it used?

A low-iodine diet helps prepare your thyroid gland for a radioactive iodine test or treatment. Your thyroid gland holds most of the iodine in your body. With a low-iodine diet, the amount of iodine in your body goes down. This helps the cells in your thyroid pick up radioactive iodine better during your procedure.

How do you follow a low-iodine diet?

Your doctor may put you on a low-iodine diet for 1 to 2 weeks before your treatment or test. You might continue the diet for a couple of days afterward. Your doctor will give you instructions about what foods to avoid and for how long.

You may need to avoid certain vitamins and mineral supplements because these products often contain small amounts of iodine. You may get a list of foods to avoid. Find more information, including a free low-iodine cookbook, to help you follow a low-iodine diet.

Foods to avoid include:

• Iodized salt.
• Processed, canned, dried, salted, or cured meats and poultry. These include deli meats, bacon, sausage, and hot dogs.
• Salted nuts and seeds.
• Canned or packaged foods with added salt. These include canned beans, lentils, and store-bought sauces and soups.
• Soybeans (edamame) and soy foods like tofu, soy sauce, and fortified soy beverage. You do not need to avoid soy oil and soy lecithin.
• Milk and other dairy foods.
• Milk chocolate and any chocolate foods that contain milk.
• Whole eggs and egg yolks.
• Store-bought grain products like bread, tortillas, and egg noodles.
• Seafood and all seafood products, including shellfish and imitation crab.
• Seaweed, kelp, and any other sea vegetables.
• Foods, drinks, and medicines that contain the food dye erythrosine (FD&C Red No. 3).

Foods that are okay to eat include:

• Fresh meat and poultry.
• Egg whites.
• Potatoes without the skin and rice.
• Homemade breads, cakes, desserts, and tortillas made without iodized salt or high-iodine ingredients like dairy or whole eggs or egg yolks.
• Fresh or frozen vegetables.
• Dried beans, peas, and lentils, or canned beans, peas, and lentils with “no added salt.”
• Fresh or frozen fruits and fruit juices.
• Unsalted nuts and seeds.
• Dark chocolate.