Iodine for babies and children: how much do they need?

by Dr Miriam Martinez-Biarge

Iodine is a vital nutrient at all ages.

Our thyroid gland takes iodine from the blood, combines it with the amino acid tyrosine and makes thyroid hormones: thyroxine (T4) and triiodothyronine (T3). Thyroid hormones control cardiac, muscle and digestive functions, body temperature, menstrual cycles, cholesterol levels and body weight.

Thyroid hormones also regulate bone growth and brain development, and that is why a normal thyroid function is essential during pregnancy and the first years of life: iodine deficiency or insufficient thyroid function (hypothyroidism) can cause poor growth and impaired intellectual function in babies and children. Iodine deficiency during pregnancy increases the risk of congenital anomalies and miscarriage.

How much iodine do babies and children need?

The recommended daily intakes in the UK are: 70 micrograms (mcg) for 1-3 year old children, 100 mcg for 4-6 year olds, 110 mcg for 7-10 year olds and 130 / 140 mcg for 11-18 year old girls and boys respectively. Pregnant and breastfeeding women are advised to take 200 mcg a day.

Where is iodine found?

Iodine is naturally abundant in the oceans. Sea vegetables and fish have the largest concentrations of iodine. Dairy products are one of the main sources of iodine in the UK’s diet, because cows’ feed is fortified with iodine and because of the use of iodine-containing disinfectants during milking.

The iodine content of land plant foods depends on the iodine present in the soil. This varies by country and region and is generally low in the UK and Europe. Fruits, vegetables, grains and legumes do not provide more than 15-20% of the iodine we need. Therefore, adults and children on plant-based diets need to use iodine supplements to meet their daily requirements. During the first year iodine requirements are well covered with breastmilk or formula milk and babies do not needto take supplements. From one year onwards vegan children should start taking iodine supplements. There are not many iodine supplements designed for children, but adult doses (150 mcg) can be given to them 3-4 times per week depending on the age. Most multivitamins for children include iodine.

Some plant milk brands have recently started to fortify their milks with iodine, and this can be a great way to provide iodine for your kids. If 1-2 glasses of plant milk are part of your child’s daily diet, choosing one of the following brands could help them to meet their needs without the need for supplementation (all are also calcium fortified):

Does your family’s diet include sea vegetables (nori, wakame, dulse, Irish moss, kombu, hijiki, arame) on a regular basis?

Sea vegetables are an excellent source of iodine, but they may also provide too much, which can cause thyroid problems. Check with a dietitian that you are not taking too much iodine from sea vegetables. Babies under 1 year old should not be offered sea vegetables.