Iodine: Why Your Thyroid and Immune System Need It

Iodine is a trace mineral your body cannot make, yet it cannot live without it. Its most important job is in the thyroid, the butterfly-shaped gland at the base of your throat, which uses iodine to build the hormones that set the pace of your whole body: how warm you feel, how fast you burn energy, how your heart beats and how your brain develops. Iodine also has a long history outside the body as a powerful antiseptic, used to cleanse wounds and water. For such a tiny amount, it carries enormous responsibility.

Because iodine is scarce in many soils, especially far from the sea, whole regions of the world once suffered from iodine deficiency. That is why it was added to salt, one of the great public health stories of the last century.

What iodine does

• Thyroid hormones. The thyroid combines iodine with an amino acid to make the hormones T4 and T3. The numbers refer to how many iodine atoms each one carries.
• Growth and development. Iodine is essential for a baby's brain development during pregnancy and early childhood. The World Health Organization has called iodine deficiency the world's leading preventable cause of intellectual disability.
• Energy and warmth. Thyroid hormones help regulate metabolism and body temperature.
• Immune support. Iodine is found in other tissues too, and researchers are exploring its role in immune defense. White blood cells can use iodine-containing compounds as part of how they fight microbes.

Why it is in table salt

In the early 1900s, parts of the United States around the Great Lakes and the Pacific Northwest were called the "goiter belt," because so many people had swollen thyroid glands from too little iodine. In 1924, iodized salt was introduced in Michigan, and goiter rates dropped dramatically. Today about 120 countries iodize salt. It remains one of the simplest and most effective nutrition programs in history.

Here is a gentle note: if you switch completely to unrefined sea salt or pink salt, which usually contain only small amounts of iodine, make sure you get iodine from food.

How much do you need?

The US National Institutes of Health gives these recommended amounts:

• Adults: 150 micrograms (mcg) a day
• Pregnancy: 220 mcg a day
• Breastfeeding: 290 mcg a day
• Upper limit for adults: 1,100 mcg a day

More is not always better. Too much iodine can also upset the thyroid, especially in people with existing thyroid conditions.

The best food sources

• Seaweed: kelp, nori, wakame, dulse. Seaweed can be very high in iodine, and amounts vary enormously. Kelp especially can contain far more than the daily upper limit in small servings, so enjoy it in moderation.
• Seafood: cod, shrimp, tuna and other ocean fish.
• Eggs: especially the yolk.
• Dairy: milk, yogurt and cheese often contain iodine.
• Iodized salt: about a quarter teaspoon provides a good portion of daily needs.

Iodine as an antiseptic

Iodine was discovered in 1811 in seaweed ash. By the mid-1800s it was being used to clean wounds, and Lugol's iodine, a solution created by French physician Jean Lugol in 1829, became a common remedy of its era. Today, iodine solutions such as povidone-iodine are still used on skin before surgery because iodine kills a wide range of bacteria, fungi and other microbes on contact.

In traditional and natural health circles, iodine is also discussed for internal cleansing and against parasites. These uses are traditional and not established by research, and taking concentrated iodine by mouth can be risky. Please never drink antiseptic iodine, and talk with a trusted practitioner before using any iodine supplement.

Signs iodine may be low

These are reflections, not a diagnosis: feeling cold often, low energy, dry skin, thinning hair, a swollen neck, or trouble concentrating. Because these overlap with many other things, testing with a practitioner is the way to know.

A spiritual note: the throat and the sea

The thyroid sits at the throat chakra, the center of truth and expression, and iodine comes to us mostly from the sea. There is something poetic in that: the ocean helps give us our voice. When you eat seaweed or sea fish, you can offer a quiet thank you to the waters.

Iodine is part of our Minerals Series. Continue with Why Your Body Needs Salt, Iron Deficiency and Copper, Zinc and the Mineral Balance.

With love and light,
Infused Lights