What is iodine deficiency?

Iodine deficiency happens when you don’t have enough iodine in your body. Iodine is a trace element that is essential for normal brain growth.

Iodine is needed to make thyroid hormones. Not having enough iodine means that your body doesn’t make enough thyroid hormones.

This causes a group of conditions called 'iodine deficiency disorders'. It’s also the greatest cause of avoidable brain damage in the world.

Learn about the role of iodine and your health.

Find out which foods are high in iodine.

What are the symptoms of iodine deficiency?

Many people with mild iodine deficiency don’t have any symptoms.

In other people, low iodine levels cause goitre or hypothyroidism (underactive thyroid).

Symptoms of hypothyroidism are:

• dry skin
• bradycardia (weak, slow heartbeat)
• tiredness
• unexpected weight gain
• constipation
• depression
• hypertension (high blood pressure)

During pregnancy, iodine deficiency can cause:

• congenital disorders (a condition your baby is born with)
• brain damage (this used to be called cretinism)
• miscarriage
• stillbirth

Who is at risk of iodine deficiency?

While anybody can get iodine deficiency. It’s more common in people who are pregnant or breastfeeding (who have higher iodine needs), and newborn babies.

People who eat small amounts of iodine containing foods have a greater chance of becoming iodine deficient. This includes people who:

• are vegans
• have food allergies
• are lactose intolerance

What causes iodine deficiency?

Iodine deficiency happens when you don’t have enough iodine in your diet.

In some parts of Australia, there isn’t enough iodine in the soil. Foods grown in these areas don’t have much iodine. This means that people eating these foods have a greater chance of becoming iodine deficient.

To address this problem, all manufactured breads in Australia must be fortified with iodised salt, except for organic bread. This helps to make sure that most people get enough iodine.

When should I see my doctor?

See your doctor if you have symptoms of low iodine levels.

You should also see your doctor if you’re planning a pregnancy. Iodine is very important during pregnancy to make sure that your baby grows properly.

How is iodine deficiency diagnosed?

Your doctor will examine you and may arrange a urine (wee) test or a thyroid stimulating hormone (TSH) blood test.

You may need further tests, such as an ultrasound to look at the thyroid gland.

If you are iodine deficient, your doctor may refer you to an endocrinologist (a doctor who specialises in hormones).

How is iodine deficiency treated?

Your treatment for iodine deficiency will depend on your symptoms.

You may need to:

• eat more foods that contain iodine
• take iodine supplements
• use iodised table salt

If you have a thyroid condition, speak to your doctor before taking iodine supplements.

If you have hypothyroidism, you may need to take a synthetic form of thyroid hormone.

What are the complications of iodine deficiency?

Iodine deficiency is the most common cause of avoidable intellectual disability in the world.

Hypothyroidism during pregnancy can cause:

• pre-eclampsia
• miscarriage
• premature birth

Other complications of hypothyroidism are:

• angina (chest pain)
• atrial fibrillation (when your heartbeat isn’t normal)
• osteoporosis

How is iodine deficiency prevented?

Most people get enough iodine from eating foods high in iodine, like seafood. You can also eat packaged bread to increase the iodine in your diet.

The National Health and Medical Research Council (NHMRC) advises that you take an iodine supplement of 150 micrograms a day if you are:

• planning a pregnancy
• pregnant
• breastfeeding

If you have a thyroid condition, speak to your doctor or midwife before taking iodine supplements.

Read more about iodine and your health.

Resources and support

• Visit Eat for Health to learn about the Australian dietary guidelines.
• Visit Nutrition Australia to read about iodine and for recipes that are rich in iodine.
• Read the NHMRC factsheet on iodine supplementation before conception, during pregnancy and while breastfeeding.
• Pregnancy, Birth and Baby has information on vitamins and supplements in pregnancy.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.