An iodine deficiency causes your thyroid not to produce enough thyroid hormone, which can cause other health conditions. Treatment typically involves increasing your iodine intake.

Iodine deficiency affects about 2.2 billion people worldwide. It’s most common in developing countries where people may lack access to enough healthy food. But it can also affect people who lack an adequate diet or whose bodies don’t correctly process iodine.

Pregnant people and people who are nursing require more iodine. Because of this, they’re likely to experience a deficiency if they don’t make a conscious effort to consume high-iodine foods or take a supplement containing iodine, such as a prenatal vitamin.

Your body needs a certain amount of iodine to make thyroid hormone. Thyroid hormone controls your metabolism and other essential body functions.

A lack of iodine can cause your thyroid gland to become enlarged, along with other problems.

Your body doesn’t naturally make iodine, so your diet is the only way to get it. Adults typically require 150 micrograms (mcg) per day. Pregnant people need 220 mcg per day, while those who are nursing need 290 mcg daily.

Iodine is found in many types of foods. Sources can include:

  • iodized table salt and foods prepared with it, such as pasta boiled in water with iodized salt
  • fish, including cod
  • seafood, including shrimp and oysters
  • seaweed, including nori and kombu
  • eggs
  • dairy products, including yogurt, cheese, and milk
  • meats, including beef and beef liver

Iodine deficiency can cause symptoms relating to low levels of thyroid hormone. Infants born to pregnant people with an iodine deficiency may experience permanent issues.

Signs and symptoms of iodine deficiency can include:

Swelling of the thyroid glands in the neck

This can cause a visible lump, called a goiter, to form on your neck.

Low levels of thyroid hormones (hypothyroidism)

Hypothyroidism typically causes symptoms that can include:

In infants, hypothyroidism can cause symptoms like:

  • frequent choking
  • large tongue
  • puffy face
  • constipation
  • poor muscle tone
  • extreme sleepiness

In children and teens, this condition may cause:

  • poor growth
  • delayed tooth development
  • delayed puberty
  • poor mental development

Cognitive issues

Symptoms can include:

  • low IQ
  • trouble learning
  • mental disabilities (especially in children if the birthing parent had an iodine deficiency while pregnant or nursing)

In pregnant people

Signs and symptoms of iodine deficiency in pregnant people can include:

  • enlarged thyroid and goiter
  • elevated levels of thyroxine and triiodothyronine, two thyroid hormones
  • elevated levels of thyroid-stimulating hormone

When untreated, iodine deficiency can lead to severe hypothyroidism. Complications may include:

  • heart disease and related disorders, such as an enlarged heart and heart failure
  • mental health issues, such as depression and cognitive impairment
  • damage to the body’s peripheral nerves, known as peripheral neuropathy
  • impaired ovulation, which may cause infertility in females

Low amounts of thyroid hormone in pregnant people can increase their child’s risk of congenital disabilities. Pregnancy-related issues that iodine deficiency can cause include:

Myxedema is a rare but life threatening complication of hypothyroidism. Many health conditions, including iodine deficiency, cause it. Symptoms can include:

  • low systolic and high diastolic blood pressure
  • low heart rate
  • intolerance to cold temperatures
  • extreme fatigue
  • coma

Myxedema is an emergency condition that requires immediate medical treatment. If you experience any of its symptoms, call 911 or your local emergency services.

If your doctor suspects you have an iodine deficiency, they usually check your iodine levels to confirm a diagnosis. Tests can include:

  • Urine test: You can get results in minutes, but it’s not as accurate as some other iodine tests.
  • Blood test: This is a simple and accurate test for iodine levels in the body, but it takes more time to read than a urine test.
  • Iodine patch test: The iodine patch test is a test where doctors paint a patch of iodine on your skin and check how it looks 24 hours later. This test is inexpensive and relatively quick, but may not be as accurate as others.
  • Iodine loading test: This test measures how much iodine you excrete in your urine over a 24-hour period. You need to collect every urine sample you have in a 24-hour period. It can be more accurate than other tests.

Treatment for an iodine deficiency typically involves increasing your iodine intake. This can include:

Eating an iodine-rich diet

Iodine deficiency is best corrected by incorporating more iodine-containing foods into your diet. People who may not be getting enough iodine through food often include:

  • vegans
  • pregnant people
  • people who are nursing
  • people who do not use iodized salt
  • people who eat few to no dairy products, seafood, and eggs

Read more: A healthy diet during pregnancy »

Taking iodine-containing supplements

A doctor may recommend iodine supplements for an iodine deficiency.

Iodine supplements containing potassium are most readily absorbed by the body. You may want to choose supplements that contain potassium iodide and potassium iodate.

But try to avoid iodine supplements in excess of 150 mcg per day. This could cause an iodine overload, which is also harmful to the thyroid.

Most people with iodine deficiency can fix their health issues by changing their diet and adding iodine supplements.

Medication

Doctors may recommend that people with hypothyroidism, especially infants and children, take levothyroxine (Synthroid, Tirosint, Levoxyl). This medication treats an underactive thyroid.

The doctor may adjust your dose every 6 to 8 weeks until your level of thyroid hormone is stable.

Thyroid hormone

People with myxedema typically require hospitalization.

At the hospital, doctors typically give intravenous fluids and other stabilizing treatments. They may also administer thyroid hormone to correct the condition.

After a person with myxedema is stable, the doctor typically monitors their thyroid function and determines if a change in diet to ensure they are consuming enough iodine can keep their hormone levels stable.

Recovery timeline

How long it takes to recover from an iodine deficiency can depend on the severity of the condition and your thyroid function.

It can take 24 weeks to improve a mild iodine deficiency with iodine supplementation.

If caught early, iodine deficiency can be reversed with few to no side effects. However, if it’s caught after complications arise, many complications — especially in children — can be permanent.

But even if complications have developed after an iodine deficiency, making sure you get enough iodine going forward can prevent complications from getting worse.

Iodine deficiency can cause your thyroid not to produce enough thyroid hormone. This may cause other health conditions, including goiter and hypothyroidism.

Treatment typically involves increasing your intake of iodine, whether through diet, supplements, or both.