What is iodine?
Iodine is a nutrient found in most foods. But it's usually found in only small amounts.
Iodine is essential for the brain development of unborn babies and young children.
Low iodine levels in a diet can cause:
- poor growth and development in infants and children
- thyroid diseases
- goitre (swelling of the thyroid gland in the neck).
How much iodine do you need?
The recommended dietary intake (RDI) for iodine depends on your age and life stage:
- children over 14 and adults need about 150 micrograms of iodine a day
- pregnant women need about 220 micrograms
- breastfeeding women need about 270 micrograms
- children under 14 need less.
If you have questions about the right iodine intake for you, ask your doctor or other healthcare professional.
How to get enough iodine in your diet
You can get iodine by:
- eating iodine-rich foods
- eating food with iodine added.
Iodine-rich foods include:
- milk and milk products
- eggs
- seafood
- foods that contain seaweed, like sushi.
New Zealand soils contain little iodine. This means vegetables, fruits, and grains grown here also have low levels.
Food with iodine added includes store-bought bread and iodised salt.
Pregnant and breastfeeding women need more iodine
When you're pregnant or breastfeeding, you need more iodine than normal. It's needed to support your baby's brain development. The Ministry of Health advises pregnant and breastfeeding women to take a daily iodine-only tablet (150 micrograms), along with eating iodine-rich foods.
Foods fortified with iodine
Fortification is when extra nutrients (such as iodine) are added to food and drinks during manufacturing.
Vitamins and minerals added to food – Food Standards Australia New Zealand
Iodised salt
Iodine has been added to salt since 1924. Use iodised salt in cooking or at the table to ensure you get enough iodine. But remember to limit how much salt you eat.
Note that some rock or sea salts sold in New Zealand are not iodised. It is important that you check the label.
Read more about salt and your health
Iodised salt in bread
Since 2009, bread manufacturers have had to use iodised salt in most of their products.
Studies had found mild to moderate iodine deficiencies in some age groups, including children. Adding iodine to this common food helps ensure we are getting enough.
Are iodine-fortified foods labelled?
Yes. Foods that contain iodised salt, like bread, will list this in the ingredients.
Can you have too much iodine?
High levels of iodine can cause thyroid problems.
Products made with brown seaweed may contain very high iodine levels. It may be unsafe to eat these products more than every once in a while, especially if you're pregnant or breastfeeding.
However, most people on a typical diet are unlikely to get enough iodine to affect their health.
Monitoring iodine levels in New Zealand
MPI and the Ministry of Health:
- regularly check the iodine content of foods
- estimate New Zealanders' dietary intake of iodine
- survey the iodine status of the population.
The most recent surveys show New Zealanders' iodine intake has increased significantly since fortification began. This suggests most adults and children are getting enough iodine.
Find out more
National nutrition surveys – Ministry of Health
Who to contact
If you have questions about iodine in food, email info@mpi.govt.nz
