Digestion and Absorption of Iodine

Iodine is a trace mineral that's usually found in the form of iodide. It's needed for your thyroid gland to make thyroid hormones called thyroxine and triiodothyronine. Iodine is also needed for your immune system and might help treat fibrocystic breast disease. It's available in supplemental form, but speak to your doctor before taking iodine supplements.

Digestion and Absorption

Iodine can be bound to amino acids, or it can be free, usually in the form of iodate or iodide ions. Iodide is the easiest form to absorb, so most of the bound iodine and iodate is converted to iodide by glutathione. The iodide ions are easily absorbed through the walls of the digestive tract in the stomach and small intestine. After it's absorbed, most of it concentrates in the thyroid gland. Some of it also accumulates in the ovaries, skin, and salivary, gastric and mammary glands.

Food Sources

Iodine is found in plant and animal sources of food that are also rich in protein. However, the amount of iodine varies greatly, depending on the amount of iodine in the soil where the plants were grown, or how much iodine was in the animals' feed. Ocean fish, seaweed and seafood contain large amounts of iodine. According to the Office of Dietary Supplements, 90 percent of households in North and South America use iodized salt.

Iodine Deficiency

Iodine deficiency during pregnancy can have a negative impact on fetal growth and development, possibly leading to brain and central nervous system damage. Low intakes of iodine can also cause hypothyroidism and goiter, which is an enlarged thyroid gland in the neck. The Food and Nutrition Board of the Institute of Medicine sets the dietary reference intake for adults at 150 micrograms per day. Women who are pregnant need 220 mcg per day, and women who are breastfeeding need 290 mcg per day.

Supplement Precautions

According to the University of Maryland Medical Center, iodine supplements are used to prevent goiter, help treat fibrocystic breast disease and reduce the risk of thyroid cancer after radiation exposure. Iodine might interact with anti-thyroid drugs, lithium and warfarin. High doses might damage the thyroid gland and increase your risk of thyroid diseases. Speak to your doctor before taking iodine supplements.

Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker before leaving the house.