What is iodine?

Iodine is a trace element that’s essential for normal growth and metabolism. Your body needs iodine to make thyroid hormones.

These hormones are needed for your brain and nerves to develop and function.

Find out more about iodine and your health.

What foods are high in iodine?

Iodine is found in many foods. The amount of iodine that your food contains depends on where they are grown and how they are made.

Some parts of Australia have soils that are low in iodine. This affects the amount of iodine in the food grown in the soil. This may increase your chance of being iodine deficient.

Foods high in iodine are:

• seafood — fish and prawns
• eggs
• seaweed and seaweed products
• packaged bread
• dairy foods — milk, yoghurt and cheese

Plant-based milks are not fortified with iodine.

Here are some common foods and how much iodine they have:

Bread

Since 2009, manufactured bread has been made with iodised salt (salt that has iodine). This helps to lower rates of iodine deficiency.

Organic bread and mixes for making bread at home do not have to use iodised salt. It’s important to check the food label to see if the bread has iodine.

Salt

Iodised table salt can be a good source of iodine. You can buy iodised table salt in the supermarket. However, eating too much salt is linked to hypertension (high blood pressure). Sea salt doesn’t contain much iodine.

How much iodine do I need?

How much iodine you need depends on how old you are.

Most adults need 150 micrograms of iodine a day. Children and adolescents need between 90 and 150 micrograms of iodine a day.

Find out more about how much iodine you need.

What if I am pregnant or breastfeeding?

You need more iodine if you are pregnant (220 micrograms a day) or breastfeeding (270 micrograms a day).

You should also take an iodine supplement of 150 micrograms a day, when planning a pregnancy, pregnant or breastfeeding.

Iodine helps your baby’s brain and nervous system to grow properly. Mild iodine deficiency is linked to a lower intelligence quotient (IQ).

Ask your doctor or midwife about iodine supplements.

Should I take an iodine supplement?

Most people will get enough iodine in their diet.

You should take an iodine supplement of 150 micrograms a day when you’re:

• planning a pregnancy
• pregnant
• breastfeeding your baby

If your pregnancy isn’t planned, start taking an iodine supplement as soon as you find out you’re pregnant.

If you have a thyroid condition you should speak with your doctor or midwife before taking an iodine supplement.

Do iodine supplements cause side effects?

Too much iodine can cause the same symptoms as iodine deficiency, such as:

• goitre
• hyperthyroidism
• hypothyroidism
• more thyroid stimulating hormone
• thyroiditis (when your thyroid is inflamed)
• thyroid cancer

Iodine supplements can interact with some medicines, such as:

• angiotensin-converting enzyme (ACE) inhibitors — used to treat high blood pressure
• antithyroid medicines — used to treat hyperthyroidism
• potassium-sparing diuretics

Always talk with your doctor or pharmacist before starting a supplement.

Resources and support

• Visit Eat for Health to learn about the Australian dietary guidelines.
• Visit Nutrition Australia for more information about iodine and your health.
• Read the National Health and Medical Research Council (NHMRC) factsheet on iodine supplementation for pregnant and breastfeeding women.
• Read about the essential vitamins and minerals you need during pregnancy on the Pregnancy, Birth and Baby website.

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.