What is iodine?

Also called iodide, iodine is a type of mineral that’s naturally found in the earth’s soil and ocean waters. Many salt water and plant-based foods contain iodine, and this mineral is most-widely available in iodized salt.

It’s important to get enough iodine in the diet. It regulates hormones, fetal development, and more.

If your iodine levels are low, your doctor might recommend supplementation. You shouldn’t take supplements without checking with your doctor first.

Read on to learn more about the uses and side effects of iodine, plus recommended daily amounts by age.

11 uses of iodine
Iodine is considered an essential mineral for our bodies. It’s particularly important during pregnancy, and exposure in the womb may even help prevent certain health conditions later in life.

The following is a list of some of the most important uses and how they benefit the body.

1. Promoting thyroid health
Iodine plays a vital role in thyroid health. Your thyroid gland, which is located at the base of the front of your neck, helps regulate hormone production. These hormones control your metabolism, heart health, and more.

To make thyroid hormones, your thyroid takes up iodine in small amounts. Without iodine, thyroid hormone production can decrease. A “low” or under active thyroid gland can lead to a condition called hypothyroidism.

Given the wide availability of iodine in western diets, thyroid health isn’t typically impacted by low iodine levels in the United States.

You can get enough iodine from your diet by eating dairy products, fortified foods, and salt water fish. Iodine is also available in plant foods that grow in naturally iodine-rich soil. You also can get the mineral by seasoning your food with iodized salt.

While iodine promotes overall thyroid health, too much iodine can have a negative effect on the thyroid gland. That’s why you shouldn’t take iodine supplements without your doctor’s recommendation.

2. Reducing risk for some goiters
A goiter is an enlarged thyroid gland. Your thyroid may become enlarged as a result from either hypothyroidism or hyperthyroidism. Hyperthyroidism is an overactive thyroid gland.

Non-cancerous thyroid nodules (cysts) can also cause thyroid gland enlargement.

Sometimes a goiter develops as a direct response to iodine deficiency. This is the most common cause of goiter worldwide, though it’s not as common a cause in the United States and other countries with access to iodine-rich foods.

Iodine-induced goiters may be reversed by adding iodine-rich foods or supplements in the diet.

3. Managing overactive thyroid gland
Your doctor may recommend a special type of iodine called radioactive iodine to treat an overactive thyroid gland. Also called radioiodine, this medication is taken by mouth. It’s used to destroy extra thyroid cells to help reduce excessive amounts of thyroid hormone.

The risk with radioactive iodine is that it can destroy too many thyroid cells. This can decrease the amount of hormone production, leading to hypothyroidism. For this reason, radioactive iodine is usually only recommended after anti-thyroid drugs have failed.

Radioactive iodine is not the same thing as iodine supplements. You should never take iodine supplements for hyperthyroidism.

4. Treating thyroid cancer
Radioiodine may also be a possible treatment option for thyroid cancer. It works in much the same way as hyperthyroid treatment.

When you take radioactive iodine orally, the medication destroys thyroid cells, including cancerous ones. It may be used as a treatment following thyroid surgery to make sure all cancerous cells have been removed from the body.

According to the American Cancer Society, radioactive iodine treatments significantly improve the chances of survival for people with thyroid cancer.

5. Neurodevelopment during pregnancy
You need more iodine in pregnancy. That’s because iodine intake during pregnancy is linked to brain development in fetuses. One review found that babies whose birth mothers had an iodine deficiency during pregnancy were more likely to grow up with lower IQ’s and other intellectual delays.

The recommended daily intake of iodine during pregnancy is 220 mcg. By comparison, the recommended amount in non-pregnant adults is 150 mcg a day.

If you’re pregnant, ask your doctor about iodine supplementation, especially if your prenatal vitamin doesn’t have iodine (many do not). Iodine supplements may also be necessary if you’re deficient in the mineral.

You’ll also need to continue monitoring your iodine intake if you’re breastfeeding. The recommended daily amount of iodine while nursing is 290 mcg. That’s because the iodine you take up from diet and supplementation is transferred via breast milk to your nursing infant. This is a crucial brain developmental period, so infants need 110 mcg per day until they’ve reached 6 months of age.

6. Improving cognitive function
The same neurological benefits of iodine during pregnancy may extend to healthy brain function during childhood. This also includes a reduced risk of intellectual disability.

It is likely your child gets all the iodine they need through their diet, but if you have any questions about their iodine intake, talk to their pediatrician.

7. Improving birth weight
As with brain development, iodine during pregnancy is associated with a healthy birth weight. One study of pregnant women with goiters found that 400 mg of iodine taken daily for six to eight weeks was helpful in correcting goiters related to iodine deficiency. In turn, there was an overall improvement in birth weight in newborns.

While iodine intake can impact a baby’s birth weight and overall development, it’s important to note that the above study focused on women in developing areas who were already deficient in iron.

Unless your doctor has determined you are iodine deficient, taking supplements aren’t likely to impact your baby’s weight at birth. In fact, taking iodine unnecessarily can cause health issues.

8. May help treat fibrocystic breast disease
It’s possible that iodine supplements or medications can help treat fibrocystic breast disease. This non-cancerous condition is most common in women of reproductive age, and it can cause painful breast lumps.

Although there is some promise that iodine might help with fibrocystic breast cysts, you shouldn’t attempt self-treatment. Only take iodine for this condition if your doctor specifically recommends it. Otherwise, you could be at risk of side effects from iodine toxicity.

9. Disinfecting water
Iodine is just one method of water disinfection. This may be especially helpful if you don’t have access to potable water due to traveling or effects from a natural disaster.

Two percent liquid iodine tincture may be added to water in five-drop increments per one quart of clear water. If the water is cloudy, add ten drops per quart.

Iodine tablets may also be used, but the instructions can vary by manufacturer.

Despite the role iodine can play in disinfecting drinking water, there’s also some concerns that it can increase total iodine intake in humans and lead to adverse health effects. Total iodine intake shouldn’t exceed 2 mg per day.

10. Protection from nuclear fallout
In the case of nuclear emergencies, the Centers for Disease Control and Prevention recommends the use of potassium iodide (KI) to protect the thyroid gland from radiation injuries. These are available in tablet and liquid formulas.

While not completely foolproof, the sooner KI is taken, the better the thyroid is thought to be protected in the event of this kind of emergency.

There are serious risks associated with KI, including gastrointestinal upset, inflammation, and allergic reaction. You’re also at increased risk for thyroid disease. Your risk for complications is higher if you already have thyroid disease.

11. Treating infections
Iodine can be used topically in a liquid form to help treat and prevent infections. It works by killing bacteria in and around mild cuts and scrapes.

Topical iodine should not be used on newborn babies. It should also not be used for deep cuts, animal bites, or burns.

Follow directions on the packaging for dosage information, and do not use for more than 10 days unless directed by your doctor.


How much iodine do you need?
To reduce our risk for iodine deficiency, the National Institutes of Health (NIH) has the following recommendations for daily intake based on age: