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Iodine deficiency

3-minute read

Iodine deficiency is the most common cause of thyroid disease and, if serious, can cause permanent brain damage and intellectual disability in babies. Many people in Australia get enough iodine from their food and iodised salt supplements. However, during pregnancy and breastfeeding, women should take iodine supplements.

What is iodine deficiency?

It is a shortage of iodine in a person's body.

Iodine is a mineral found naturally in seawater and the soil. The body needs iodine to make thyroid hormone in the thyroid gland. Thyroid hormone influences your metabolism and is essential for the development and function of the brain, nerves and bones.

You need the right amount of iodine for your metabolism and for the healthy functioning of your thyroid gland.

Find out more here about iodine and recommended iodine daily intake .

What problems can iodine deficiency cause?

In anybody, a shortage of iodine can cause:

  • goitre or enlargement of the thyroid gland in the neck
  • hypothyroidism - too little thyroid hormone, which can cause
  • constant tiredness
  • unexpected weight gain
  • difficulty learning and remembering
  • constipation
  • weak, slow heart beat
  • dry skin

If children and unborn babies have too little iodine, there can be problems with normal development including:

  • brain damage
  • intellectual disability, including the most severe form cretinism
  • low IQ
  • stunted growth

In women, iodine shortage can cause:

  • fertility problems
  • problems with pregnancy such as miscarriage, stillbirth and brain and nerve damage to the developing fetus

Who is most at risk of iodine deficiency?

While anybody can develop iodine deficiency, those most at risk are:

  • pregnant women
  • breastfeeding mothers
  • fetuses (unborn babies)
  • newborn babies

In NSW, Tasmania, Victoria and some other parts of the country, there is too little iodine in the soil, so people living there are at greater risk of iodine deficiency.

To counteract this lack of iodine in the soils and food in Australia, iodine is put in most table salts. Since 2009, mandatory iodine fortification is used in all breads that are not organic.

How is iodine deficiency diagnosed?

The doctor will do a physical examination and order a thyroid stimulating hormone (TSH) blood test. If the results show abnormal levels of TSH, you should have further tests and might be referred to a specialist endocrinologist or physician.

In Australia, newborn babies are routinely given TSH blood tests that will pick up low thyroid levels. These can be a sign of iodine deficiency or have other causes. The doctors will do urgent further tests and investigations.

How is iodine deficiency treated?

It is usually treated through eating more foods containing iodine, using iodine salt and taking iodine supplements. Other treatments may be needed.

How do you prevent iodine deficiency?

Use iodine salt and include a range of iodine-rich foods in your diet.

Seafood is rich in iodine - having seafood two to three times a week is enough for most people. There is also plenty of iodine in animal products such as meat, eggs and dairy. Seaweed is rich in iodine too.

The National Health and Medical Research Council recommends that all women who plan to get pregnant, are pregnant or are breastfeeding should take a daily iodine supplement.

Taking too much iodine can also cause thyroid problems, so don't exceed the recommended dose of supplements.

More information

The Thyroid Foundation has a factsheet about iodine supplementation for pregnant and breastfeeding women.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: February 2019

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