How to recognize the symptoms of iodine deficiency and effectively treat it

flaked sea salt — Salt is a great source of iodine.
Shutterstock

One of the earliest symptoms of iodine deficiency is goiter, which is the abnormal enlargement of your thyroid.
You may be at a greater risk of iodine deficiency if you are pregnant, vegan, or avoid salt.
To treat iodine deficiency, you should increase your intake of iodine-rich foods like seafood, or take a supplement.
Visit Insider’s Health Reference library for more advice.

Iodine is a crucial mineral for forming hormones that help us use oxygen and produce heat in the body. Iodine can be found in high amounts in salt and seafood. But, when a person does not eat enough iodine, a deficiency occurs.

Here’s everything you need to know about an iodine deficiency and how to treat it.

What does iodine do?

Iodine is ingested from food and stored in the thyroid gland.

“Its main function is to help synthesize the thyroid hormones,” says Jean Hanks, RDN, a dietitian at Bethany Medical Clinic of New York. “These hormones are involved in stimulating oxygen consumption, body heat, and metabolism rate, and play a role in the normal development of the nervous system.”

To maintain the thyroid’s proper functioning, a person must retain adequate iodine levels in their diet. If a person does not, an iodine deficiency will develop. As of 2017, there are about two billion people worldwide with an iodine deficiency.

Signs and symptoms of iodine deficiency

One condition that can result from an iodine deficiency is hypothyroidism, which is when the thyroid doesn't produce the hormones it typically creates.

This can cause symptoms like:

Fatigue
Sensitivity to cold
Irregular menstrual periods
Goiter, an abnormal enlargement of the thyroid

"If your diet is low in iodine, the thyroid gland will enlarge to attempt to take up more iodine. If left untreated, the gland can grow so large it causes difficulty breathing," says Elizabeth Klingbeil, PhD, RDN, LDN, an assistant professor in the department of nutrition & dietetics at Johnson & Wales University. This condition is often the earliest sign of an iodine deficiency.

Causes of iodine deficiency

When a person doesn't receive enough iodine through their diet or supplements, a deficiency can emerge. The amount of iodine you need changes throughout your life. The recommended dietary allowance of iodine for people at different ages is:

Infant to six months: 110 mcg
Baby seven to 12 months: 130 mcg
One to eight years: 90 mcg
Nine to 13 years: 120 mcg
14 years and older: 150 mcg
Pregnant: 220 mcg
Breastfeeding: 290 mcg

According to Klingbeil, living in a location with low iodine levels in the soil is one of the highest risk factors for an iodine deficiency. This includes areas such as the Great Lakes region of the US and mountainous areas like the Himalayas. Low levels of iodine in the soil translates to low levels of iodine in crops.

According to Hanks, other factors that could increase your risk of becoming iodine deficient include:

Being vegan, as restricting fish may cause a deficiency.
Avoiding salt, as iodized salt is a great source of the mineral.
Pregnancy, as the amount of iodine your body needs significantly increases.

Pregnant and breastfeeding people need to especially monitor their iodine intake to ensure they do not have a deficiency.

"Even a mild deficiency can affect the growth and development of the baby causing miscarriage, stillbirth, preterm delivery, and learning disabilities," says Nicole DeMasi, MS, RDN, CDCES, a registered dietitian with her own virtual private practice. "In severe cases, infants born to mothers with iodine deficiency during pregnancy can have issues with growth, hearing, and speech."

Diagnosis

If you believe you may have an iodine deficiency, a medical professional can order a urine or blood test to determine your iodine levels. Normal iodine levels are about 15 to 20 mg, the majority of which is stored in the thyroid.

"Any new or unexplainable symptoms of any kind should prompt someone to get to a doctor," says Hanks. "These would include but are not limited to a bulge in the neck, unexplained weight gain, cold sensitivity, cognitive impairment, constipation, or fatigue."

Iodine deficiency treatment

Iodine deficiency can be treated by increasing your intake of iodine-rich foods. Foods high in iodine include:

Salt (76 mcg per 1.5 g)
Seaweed (232 mcg per 10 g)
Seafood (Cod has 158 mcg per 3 oz)
Whole-wheat bread (198 mcg per slice)
Milk (85 mcg per cup)

While consuming food high in iodine may be enough to increase your levels, supplements may be needed. However, supplements should be monitored by a medical professional, as people should not consume more than their upper tolerable intake level of iodine:

One to three years: 200 mcg
Four to eight years: 300 mcg
Nine to 13 years: 600 mcg
14 to 18 years: 900 mcg
19 years and older: 1,100 mcg
Pregnant or breastfeeding at 18 years or younger: 900 mcg
Pregnant or breastfeeding at 19 years or older: 1,100 mcg

Some people may even have to undergo surgery. "If the goiter is extremely large and obtrusive, surgery may be needed to reduce the size," says Klingbeil. "Otherwise, small and unnoticeable goiters do not require further intervention past iodine supplementation."

Insider's takeaway

Iodine deficiency occurs when someone does not consume enough iodine-rich foods like seafood or iodized salt. Symptoms of an iodine deficiency include an enlarged thyroid, fatigue, and sensitivity to the cold. A doctor can diagnose iodine deficiency through a urine or blood test and help you make a plan to raise your levels.