Iodine for babies and toddlers

Why iodine matters

The body uses iodine to make thyroid hormones, which control metabolism and are needed for normal growth and development in babies (NIH). That’s why getting enough matters for babies and for pregnant and breastfeeding parents.

Iodine deficiency is uncommon in the US (NIH), and most families get enough without thinking about it. It’s worth a closer look if your family eats little or no dairy, fish or eggs, or if you’re breastfeeding.

How much babies need

The NIH amounts per day are:

• Birth to 6 months: 110 mcg
• 7 to 12 months: 130 mcg
• 1 to 3 years: 90 mcg

UK reference amounts are lower: about 60 mcg a day in the first year and 70 mcg at 1 to 3 years (NHS Stockport). See the US and UK section below.

The NIH says an upper limit can’t be set for babies under 1, and that their iodine should come only from their milk and food, not from supplements. Don’t give your baby an iodine supplement unless your doctor advises it. For children aged 1 to 3, the upper limit is 200 mcg a day from all food, drinks and supplements together (NIH).

Milk feeds come first

Breast milk contains iodine, but how much depends on how much the breastfeeding parent gets (NIH, CDC). Babies who are only breastfed rely on their parent’s iodine.

• The CDC and the NIH both advise breastfeeding parents to take a daily multivitamin or supplement containing 150 mcg of iodine. The CDC page gives this as the advice of the American Thyroid Association and the AAP. Not every prenatal or multivitamin has that much, so check the label or ask your doctor or pharmacist (CDC).
• Parents who don’t regularly eat dairy or seafood, or don’t use iodized salt, are more likely to run low while breastfeeding, the CDC says. So are people who smoke.
• In the UK, the NHS says most people can get enough iodine from a varied diet, and that people on a strict vegan diet may want to consider iodine-fortified foods or a supplement, after advice from a health professional. The NHS says taking 0.5 mg (500 mcg) or less a day from iodine supplements is unlikely to cause harm. Ask a health professional before taking more.

Formula contains iodine (NIH), so formula-fed babies get what they need from their milk.

Food sources from 6 months

Once your baby starts solids, these are the most reliable sources (NIH, NHS):

• Dairy: plain full-fat yogurt and pasteurized cheese from 6 months. Cow’s milk as a main drink from 12 months. The amount in milk varies with how the cows were fed and how equipment was cleaned (NIH).
• Fish and seafood: fish such as cod is generally rich in iodine (NIH), and an NHS dietitian leaflet names dairy and fish as the best UK sources. Other white fish like haddock work well too. Cook fish thoroughly and check for bones. See fish for babies.
• Eggs: well-cooked egg, such as hard-boiled and mashed, or omelet strips (NIH).
• Grains, fruit and vegetables have some iodine, but levels depend on the soil they grew in and are usually low (NIH, NHS).

Dairy, egg and fish are common food allergens. Offer each one on its own first, one at a time, so you can spot any reaction. If your baby has eczema or a food allergy, or there’s a family history of food allergy, eczema, asthma or hay fever, talk to your doctor or health visitor first (NHS). See how to introduce allergens.

The NHS says most people get the iodine they need from a varied, balanced diet. For babies, that means including some of these foods regularly alongside breast milk or formula.

Plant-based families

People who eat little or no dairy, seafood and eggs are among those most likely to run short of iodine (NIH).

• Plant drinks contain little iodine unless it’s added (NIH). Only some soya and oat drinks are fortified, so check the label (NHS). An NHS dietitian leaflet notes that dairy-free milks often have no iodine at all.
• Plant drinks aren’t a main drink before 12 months, and rice drinks shouldn’t be given under 5 (NHS). See plant milks for toddlers.
• Ask your pediatrician, GP or health visitor, ideally with a dietitian, whether your child needs an iodine supplement. Don’t guess the dose: too much iodine can affect the thyroid too (NIH, NHS).

See vegetarian and vegan babies for B12, iron and the other nutrients to plan for.

Seaweed: a little goes a long way

Seaweed is one of the richest sources of iodine, but the amount varies enormously, from 16 to 2,984 mcg per gram (NIH). That makes it an unreliable way to meet a baby’s needs and an easy way to give too much.

• Skip kelp and seaweed supplements. An NHS dietitian leaflet says not to use them for children, because their iodine content varies and can lead to too much.
• Brown seaweeds are the strongest. Figures quoted by the UK Committee on Toxicity give 29 to 46 mcg per gram for nori, 94 to 185 for wakame, and 241 to 4,921 for kombu (kelp). Skip kelp, kombu and wakame for babies and toddlers, including broth made with them.
• Avoid hijiki completely. The UK Food Standards Agency advises people not to eat hijiki seaweed, because it contains high levels of a form of arsenic that can cause cancer.
• Plain nori can be offered as a small pinch, crumbled finely into soft food. See seaweed.

Why not iodized salt?

Iodized salt is a common source of iodine for adults (NIH), but babies shouldn’t have added salt. The NHS says not to add salt to your baby’s food or cooking water, because too much salt isn’t good for their kidneys, and the AAP says to cook baby food without added salt. Toddlers need very little salt too. See salt and sugar for babies.

Dairy, eggs and fish give your baby iodine without the salt.

Signs of too little or too much

Both too little and too much iodine can cause problems with the thyroid. An enlarged thyroid gland (goiter), a swelling at the front of the neck, is often the first visible sign of deficiency, and high intakes can cause goiter too (NIH).

Talk to your pediatrician, GP or health visitor if:

• your family eats no dairy, fish or eggs, or your child refuses all of them
• you’re breastfeeding and not sure your supplement contains iodine
• you’re thinking about giving your child any iodine or seaweed supplement
• you notice a swelling at the front of your child’s neck

Where US and UK advice differs

• How much. The NIH sets 110 to 130 mcg a day for babies and 90 mcg for ages 1 to 3. UK reference amounts are about 60 mcg in the first year and 70 mcg at 1 to 3 years (NHS Stockport, based on the UK dietary reference values).
• Supplements while breastfeeding. The CDC and NIH advise a daily supplement with 150 mcg of iodine (the CDC credits this to the American Thyroid Association and the AAP). The NHS says most people can get enough from a varied diet and suggests fortified foods or a supplement for people on a strict vegan diet, after advice.
• Seaweed. The UK Food Standards Agency advises against hijiki for everyone. The NIH notes how widely seaweed iodine varies.