Basics of a Low Iodine Diet

Eating well on the low iodine diet

A low iodine diet is prescribed before radioactive iodine (RAI) scans and radioactive iodine treatments. It is a special diet that limits the amount of iodine that is consumed through foods and beverages. If you have to undergo RAI scans and undertake a low iodine diet, this article will help you figure out what you can and can't eat. 


The thyroid gland uses the iodine we get through water and food to produce essential hormones that regulate our metabolism. Thyroid cells are unique because they are the only cells in the body that absorb iodine. Before undergoing RAI scans and treatment, patients go on a low-iodine diet, starving the body of iodine. When a patient is given radioactive iodine (usually in capsule form), the iodine-starved thyroid cells uptake the RAI, allowing the cells to be detected by scans or destroyed for treatment (ablation).

The biggest rule of the diet is to eat foods that are low in iodine. Since most salt is iodized (meaning it has iodine added to it), you need to avoid iodized salt and foods that contain iodized salt. Instead, you can use non-iodized and kosher salt, because they do not contain iodine.

The low iodine diet is simple but requires some planning. If you eat a lot of pre-packaged or frozen foods, or if you eat out a lot, this diet might be a bit of a challenge. 


You may find conflicting information on the internet about which foods are allowed and prohibited on the diet. One source may say only potato skins should be avoided when eating potatoes, while another claims you cannot eat potatoes at all! Who should you believe?

When you read conflicting information, the best source you can go to is your doctor. This list of foods below is based on the low iodine diet recommended by The National Institutes of Health and the Thyroid Cancer Survivors Association.

Prohibited Foods

Avoid these foods on a low-iodine diet:

  • Dairy (milk, yogurt, cheese, butter, ice cream, sour cream)
  • Egg yolks
  • Seafood (anything from the ocean should be avoided, including fish, shellfish, and kelp)
  • Processed foods (pre-packaged foods, frozen dinners, deli meats, hot dogs, bacon, sausage, foods at restaurants and fast food eateries)
  • Commercial baked goods (commercially baked breads and confections)
  • Soy (includes soybeans, soy sauce, tofu, and any other food with soy)
  • Maraschino cherries
  • Chocolate (milk chocolate contains dairy; some dark chocolates may be allowed - check label)
  • Red dye #3 (check label or call manufacturer)
  • Beans (avoid red kidney beans, navy beans, lima beans, pinto beans, and cowpeas)

Foods Allowed 

Don't be disheartened by the list of foods you cannot eat! There are plenty of foods you can eat. Here are foods that are allowed on the low-iodine diet:

  • Fresh meats (no more than 5-6 ounces a day)
  • Fresh fruits and vegetables (no potato skins)
  • Frozen vegetables, without added salt (no rhubarb)
  • Vegetable oils
  • Sodas (as long as they don't contain red dye #3 - check the label or call manufacturer)
  • Unsalted peanut butter and nuts
  • Coffee and tea (non-dairy creamer is allowed)
  • Matzo
  • Homemade bread (without egg yolks, dairy or iodized salt in the ingredients)
  • Fresh and dried herbs and spices, including pepper
  • Beer, wine, and distilled alcohols (wine coolers and flavored liquors may contain red dye #3, check label)
  • Canned peaches, pineapple, and pears
  • Honey
  • Maple syrup
  • Jams and jelly (without red dye #3)

Dining Out

Eating out is almost nearly impossible while undergoing the low-iodine diet. You can't guarantee what type of salt a restaurant uses in their recipes. Foods served in fast food restaurants are mostly processed and contain salt, so they should be avoided as well. If ​you do not cook, you may want to become more kitchen savvy or think about hiring a personal chef for the time you are on a diet.

Recipes and Cookbooks

The Thyroid Cancer Survivors Association offers an excellent low-iodine cookbook online that can be downloaded for free. It boasts over 300 low-iodine recipes and is a favorite among low-iodine dieters. 

You can also follow your favorite recipes as long as the ingredients fit the criteria above. Use non-iodized salt or kosher salt instead of iodized salt in recipes. 

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