Thyroid Function and Low-Iodine Diet

Understanding the Thyroid Gland

The thyroid is a small butterfly-shaped gland located at the front of the neck. It produces hormones that regulate the body's metabolism, energy production, temperature control, heart function, muscle activity, and brain development. Proper thyroid hormone levels are essential for maintaining normal bodily functions and overall health.

What Is a Low-Iodine Diet?

A low-iodine diet is often recommended before radioactive iodine treatment for certain thyroid conditions, particularly thyroid cancer. The goal is to temporarily reduce iodine intake so that thyroid cells absorb radioactive iodine more effectively during treatment. Since iodine is present in many everyday foods, careful dietary planning is necessary.

Foods to Avoid

To minimize iodine intake, the following foods and products are generally avoided:

• Iodized salt and foods prepared with it

• Sea salt and seaweed-based products

• Kelp, dulse, and iodine-containing supplements

• Commercial baked goods that may contain iodine-based dough conditioners

• Soy-based products such as soy milk, tofu, and soy sauce

• Artificial foods containing Red Dye No. 3

• Blackstrap molasses

• Large amounts of meat and poultry

• Processed foods with iodine-containing additives

Foods to Limit

Some foods contain moderate amounts of iodine and should only be consumed in small quantities:

• Milk, cheese, yogurt, butter, and other dairy products

• Egg yolks and foods prepared with whole eggs

• Fish, shellfish, sushi, and other seafood

• Seaweed-containing ingredients such as nori, agar, carrageenan, and alginates

• Foods prepared with iodized salt

Foods Allowed on a Low-Iodine Diet

Many foods can still be enjoyed while following a low-iodine diet:

• Fresh fruits and vegetables

• Frozen vegetables without added ingredients

• Egg whites

• Homemade bread prepared with non-iodized salt

• Rice, cereals, and pasta that do not contain high-iodine ingredients

• Fresh or canned fruits

• Unsalted nuts and natural nut butters

• Vegetable oils

• Herbs, spices, and black pepper

• Sugar, honey, jams, jellies, and maple syrup

• Tea and coffee without milk, cream, or soy-based creamers

• Air-popped popcorn prepared with non-iodized salt

General Tips

Following a low-iodine diet is usually temporary and should be done according to your healthcare provider's instructions. Reading food labels carefully and choosing fresh, minimally processed foods can help reduce iodine intake while maintaining a balanced diet.