Iodine Deficiency

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is iodine deficiency?

Iodine is an element your thyroid needs to make thyroid hormones. If your diet is deficient in iodine, your thyroid gland will enlarge as it tries to increase the production of thyroid hormones. The enlarged thyroid can cause a mass in the neck known as a goiter. As thyroid levels fall, hypothyroidism develops.

Hypothyroidism slows your metabolism, causing such symptoms as fatigue, weight gain, weakness, increased cold sensitivity, constipation, dry skin, and depressed mood. Your hair and nails may be thin and brittle and, if you are female, your menstrual cycle may become abnormal. Left untreated, your skin may swell and thicken, your eyes may seem to protrude, mental function may decline, and you may ultimately lapse into a coma.

Iodine is also critical for development. Babies born of mothers who have an iodine deficiency may have problems, such as mental retardation, deaf-mutism, gait abnormalities, and growth abnormalities. Infants and children who do not get enough iodine may also have cognitive difficulties, but those may be reversible.

Iodine deficiency is rare in the United States, partly because table salt is often iodized. Dairy products, eggs, seafood, seaweed, some meats, and some breads are also dietary sources of iodine. The best method of treating iodine deficiency is avoiding it in the first place. If it develops, however, it can be treated with iodine supplementation and dietary modifications.

Severe complications of iodine deficiency are rare in the United States. If you notice an enlarging mass in your neck or develop symptoms suggestive of hypothyroidism, s eek prompt medical care. Severe depression, difficulty breathing, chest pain or pressure, change in mental status, and change in level of consciousness are complications of hypothyroidism that, rarely, may develop as a result of long-standing iodine deficiency. If these symptoms develop, s eek immediate medical care (call 911). Severe iodine deficiency also increases the risk of miscarriage and stillbirth; seek immediate medical care for any bleeding during pregnancy or concerns about fetal well-being.

What are the symptoms of iodine deficiency?

Initially, iodine deficiency may not have any symptoms. As the thyroid reacts to lower iodine levels, it tries to produce more thyroid hormones. This ultimately leads to enlargement of the thyroid.

As levels of thyroid hormones drop, the metabolism begins to slow. This can lead to weight gain, constipation, fatigue, and other symptoms. Prolonged, severe hypothyroidism resulting from an iodine deficiency is rare in the United States, but can be associated with thickening of the skin, protrusion of the eyes, severe depression, declining mental function, heart failure, and coma.

Common symptoms of iodine deficiency

Common symptoms that can occur with prolonged iodine deficiency include:

  • Constipation

  • Depressed mood

  • Dry skin

  • Fatigue

  • Goiter (enlargement of the thyroid, creating a mass in the neck)

  • Increased sensitivity to cold

  • Menstrual cycle abnormalities

  • Protrusion of the eyes

  • Thickening of the skin

  • Thinning and brittleness of the hair and nails

  • Unintended weight gain

  • Weakness

Serious symptoms that might indicate a life-threatening condition

In some cases, iodine deficiency can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • Being a danger to oneself or others, including threatening, irrational or suicidal behavior

  • Bleeding while pregnant

  • Change in level of consciousness or alertness, such as passing out or unresponsiveness

  • Change in mental status or behavior change, such as confusion, delirium, lethargy, hallucinations or delusions

  • Chest pain, chest tightness, chest pressure, palpitations

  • Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing, or choking

What causes iodine deficiency?

Our bodies do not produce iodine, so it must come from our diet. Iodine deficiency is rare in the United States, partly due to widespread use of iodized salt. Because animal feed is also often supplemented with iodine, meat and dairy products tend to be high in iodine.

Natural sources of iodine include food from the sea and from areas where the soil is rich in iodine. Worldwide, mountainous areas and inland lowlands far from the oceans tend to have iodine-poor soil. These are the areas where iodine deficiency is most common.

What are the risk factors for iodine deficiency?

The main risk factor for iodine deficiency is living in an area where the soil is iodine deficient and food from the ocean or iodized salt is not readily available. At-risk areas include:

  • Africa, especially Central Africa
  • Andes Mountains and other areas of South America
  • Eastern Europe
  • Himalayas and other areas of Asia, including Central and Southeast Asia
  • Mountainous regions of Central America and Mexico
  • The Alps

Reducing your risk of iodine deficiency

You may be able to lower your risk of iodine deficiency by:

  • Eating foods grown in iodine-rich soils
  • Eating meat and dairy products
  • Eating seafood or seaweed
  • Taking vitamin and mineral supplements that contain iodine
  • Using iodized salt

How is iodine deficiency treated?

The main treatment for iodine deficiency is avoiding it in the first place. The introduction of iodized salt has greatly reduced the occurrence of iodine deficiency in the United States and throughout many parts of the world.

Should iodine deficiency develop, the treatment is iodine replacement. Adding iodized table salt and foods high in iodine to the diet may be enough to achieve normal iodine levels. Sometimes vitamin and mineral supplements containing iodine may be used. Because iodine is so important during fetal and early childhood development, women who are pregnant or breastfeeding should take multivitamins that include iodine.

Occasionally, the thyroid gland may need to be removed. This is particularly true if a large goiter makes it difficult to swallow or breathe. Thyroid replacement hormones are required if the thyroid is removed.

What you can do to improve your iodine deficiency

You may be able to increase your iodine levels by:

  • Eating foods grown in iodine-rich soils

  • Eating meat and dairy products

  • Eating seafood or seaweed

  • Taking vitamin and mineral supplements that contain iodine

  • Using iodized salt

What are the potential complications of iodine deficiency?

In some people, especially infants and young children, complications of untreated or poorly controlled iodine deficiency can be serious. You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of iodine deficiency include:

  • Cognitive decline and personality changes

  • Coma

  • Congestive heart failure

  • Cretinism (complication of prenatal iodine deficiency associated with short stature, mental retardation, deaf-mutism, gait abnormalities, and goiter)

  • Depression

  • Goiter (enlargement of the thyroid gland in the neck)

  • Menstrual irregularities

  • Mental retardation

  • Miscarriage or stillbirth

  • Weight gain

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 16
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  1. Iodine deficiency. American Thyroid Association.
  2. Iodine in diet. Medline Plus, a service of the National Library of Medicine National Institutes of Health.