Iodine and your health
Key facts
- Iodine is a mineral that your body needs to make thyroid hormones.
- Foods rich in iodine include seafood, dairy products and iodised table salt.
- You should take an iodine supplement if you’re planning a pregnancy, are pregnant or breastfeeding.
- Too little iodine can cause iodine deficiency disorders and hypothyroidism.
- Too little iodine during pregnancy is the most common cause of intellectual disability.
What is iodine?
Iodine is a mineral that your body needs to make thyroid hormones. Babies and young children need iodine for normal growth and for brain development.
Iodine is a critical nutrient for good health at all stages of life.
Why is iodine important for my health?
Your body needs thyroid hormones to make protein and for your metabolism.
Iodine is very important during pregnancy to make sure that your baby grows properly. Babies and children need iodine so that their bones and brains can develop properly.
Iodine deficiency during pregnancy is the most common cause of intellectual disability. Deficiency of Iodine during pregnancy and in early infancy can cause problems that last your baby’s lifetime.
Radioactive iodine treatment is sometimes used to treat certain thyroid conditions. If you need this treatment, your doctor will help you change to a diet that’s low in iodine.
Where does iodine come from?
Iodine is found in many foods such as:
- seafood — fish and prawns
- dairy products
- eggs
- packaged bread
Some parts of Australia have soils that are low in iodine. This affects the amount of iodine in any food grown and may increase your chance of being iodine deficient.
In Australia, iodised salt must be used in the manufacture of bread. This helps to lower rates of iodine deficiency.
Plant based milks do not normally contain iodine. Learn more about foods high in iodine.
How much iodine do I need?
How much iodine you need depends on your age.
Most adults need 150 micrograms of iodine a day. You need more iodine if you are pregnant or breastfeeding.
| Stage of Life | Recommended dietary intake* of iodine (micrograms per day) |
|---|---|
| 0-6 months | 90 |
| 7-12 months | 110 |
| 1-8 years | 90 |
| 9-13 years | 120 |
| 14-18 years | 150 |
| Adults | 150 |
| During pregnancy | 220 |
| While breastfeeding | 270 |
*Recommended dietary intake (RDI): is the average daily dietary intake level that is needed to meet the nutrient requirements of nearly all (97–98%) healthy people in a certain life stage and gender group.
Can I have too little iodine?
Too little iodine can cause hypothyroidism (underactive thyroid). Symptoms of hypothyroidism are:
- tiredness
- constipation (difficulty pooing)
- weight gain
- depression
Goitre (a lump in your neck due to an enlarged thyroid gland) is less common.
Learn more about iodine deficiency.
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Can I have too much iodine?
Too much iodine can cause the same symptoms as iodine deficiency, such as:
- goitre
- hypothyroidism
- higher levels of thyroid stimulating hormone
Too much iodine can also cause:
- hyperthyroidism
- thyroiditis (when your thyroid is inflamed)
- thyroid cancer
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Should I take iodine during pregnancy?
You should take an iodine supplement of 150 micrograms a day, when planning a pregnancy, pregnant or breastfeeding.
This helps your baby’s brain and nervous system grow properly. Mild iodine deficiency has been linked to a lower intelligence quotient (IQ).
Iodine supplements aren’t advised for people with some thyroid conditions. Check with your doctor, pharmacist or midwife before taking an iodine supplement.
Resources and support
- Visit Nutrition Australia to learn more about 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.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: April 2025
