8 Silent Signs of an Iodine Deficiency

Updated: Mar. 13, 2024

Do you take in enough iodine? What happens if you don't? Find out the warning signs of iodine deficiency.

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What is an iodine deficiency?

If you don’t know much about the mineral iodine, you should, because it’s pretty important. “Iodine is necessary to make thyroid hormones that regulate growth, development, and metabolism,” says Elizabeth Ward, MS, RD, author of Expect the Best. Because the body doesn’t make iodine itself, the mineral is considered essential, according to the American Thyroid Association.

Iodine needs vary depending on life stage. Adults require 150 micrograms per day, according to the National Institutes of Health. During pregnancy, that need jumps to 220 micrograms daily, and anyone who is breastfeeding requires 290 micrograms daily.

While iodized salt provides iodine, several other sources exist. These include ocean-caught or farmed fish and shellfish, milk, cheese, eggs, and vegetables grown in iodine-rich soil. “Experts suggest at least eight ounces of seafood weekly for adults, and eight to 12 ounces of seafood weekly for pregnant and breastfeeding women,” says Ward. Seaweed and sea vegetables also offer iodine, adds Isabel K. Smith, RD, a dietitian in New York City. Get a dose of iodine-containing foods by whipping up miso-glazed salmon, protein French toast, or a vanilla bean smoothie.

With the introduction of iodized salt, iodine deficiency is much less common than it used to be. But it can still occur. About 30 percent of the world’s population is at risk, reports the American Thyroid Association. Watch out for these nine signs of iodine deficiency.

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Iodine deficiency symptoms

The signs of being low in this mineral can be maddeningly vague, but if you keep suffering a combination of the following symptoms, you may want to have your doctor check your iodine levels.

You feel tired or depressed

“Iodine, an essential micronutrient, is found in every tissue in the body,” says Nancy M. DiMarco, PhD, RDN, CSSD, professor emerita of nutrition and food sciences at Texas Woman’s University in Denton. “The only known function of iodine is its role in the production of the thyroid hormones, thyroxine and triiodothyronine.” In hypothyroidism, the thyroid is underactive—and the body can’t make enough of the thyroid hormones to keep the body running efficiently. Symptoms of hypothyroidism include fatigue, constipation, weight gain, and these other silent symptoms.

Your skin is dry, your hair is thinning, or you feel sensitive to the cold

Additional signs of hypothyroidism include dry skin, sensitivity to cold, hair loss, and muscle weakness. “Women have an eight times greater risk of developing hypothyroidism than men, making it predominantly a women’s health concern,” says DiMarco. “Although women may develop hypothyroidism at any age, incidence increases with age—especially after menopause.” Find out how to tell if you have a hidden thyroid problem.

Your work is suffering

“In adults, mild to moderate iodine deficiency can impair mental function and work productivity,” says Ward. She explains that these are symptoms of hypothyroidism. “We tend to think of iodine deficiency as a problem of developing countries,” she says. “But many Americans, especially pregnant and lactating women, may not be getting enough because they don’t eat foods that are rich in iodine.”

You have a large lump on your neck

A goiter is the enlargement of the thyroid and is a visible sign of low iodine intake. Goiters appear at the base of the front of the neck. “A goiter is usually the earliest sign of low iodine intake,” says Ward. “The salt that’s added to processed commercial foods does not contain iodine—and since many Americans rely on processed foods, they may not be getting adequate iodine.” Find out what standard thyroid testing won’t tell you.

You feel like you’re choking when you lie down

A large goiter may cause you to have a hard time breathing and swallowing. When you’re lying down, you may feel like you’re choking, according to the American Thyroid Association.

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You’re having problems during pregnancy

“During pregnancy, the body needs thyroid hormones, which require adequate iodine to produce,” says Ward. “[These thyroid hormones] make myelin—which surrounds and protects nerve cells, helping them to communicate properly. Moms who are severely iodine deficient are at risk for miscarriage and stillbirth.” See which foods thyroid experts avoid.

“Iodine deficiency has multiple adverse effects on growth and development of the fetus,” says DiMarco. “Iodine deficiency in pregnancy impairs the neurological development of the fetus.” She explains that iodine deficiency in a pregnant mother can lead to irreversible brain damage for the baby. “Iodine deficiency is the leading cause of preventable mental retardation in the world,” she says. In addition, inadequate iodine intake in children limits brain development and may affect intelligence, adds Ward.

An iodine deficiency during pregnancy may also lead to stunted growth and other problems for the child, notes Ward. “Iodine deficiency during pregnancy has been associated with ADHD in children,” she adds. “Experts suggest pregnant and breastfeeding women and women who may become pregnant take 150 micrograms of potassium iodine as a supplement daily. The body absorbs potassium iodine well, and it’s often the form found in regular multivitamins.” Learn the silent signs you aren’t getting enough vitamins.

Iodine deficiency test

Curious about your iodine levels? If you were to get your levels tested, your doctor would likely prescribe a urine test to determine your urinary iodine concentration. This is because iodine leaves the body via urine. The test results would indicate whether you have an iodine deficiency.