How Much Iodine Do Children Need? A Guide by Age

Children aged 1–8 need 90 µg of iodine a day, ages 9–13 need 120 µg, and teenagers need 150 µg. Iodine needs are small in weight but important in function because the thyroid uses iodine to make thyroid hormones.

Iodine intake is unusually dependent on geography, farming practices and whether household salt is iodised. Sea salt, pink salt and gourmet salts are not automatically iodised. That means two families eating similar meals can have different iodine intake depending on the labels of salt, dairy alternatives and fortified foods.

How much iodine children need, by age

The figures below come from the US Food and Nutrition Board tables published by the NIH. Reference systems can differ between authorities, so treat these as planning values for healthy children rather than a prescription. Frank Fruities Kid’s Multi is intended for ages 3+, so the first product comparison is age three rather than infancy.

Why the label percentage is not your child’s percentage

EU supplement labels carry adult nutrient reference values from Annex XIII of Regulation 1169/2011 — so the “% NRV” on a children’s product is still measured against an adult. It makes products comparable on a shelf; it does not tell you what share of a child’s own requirement a serving covers. Read the amount in micrograms first, then the age table above. We cover the percentage itself in more detail in is 100% NRV a target, a minimum or a maximum?

Iodine, thyroid hormones and children’s growth

Iodine contributes to normal cognitive function, normal energy-yielding metabolism and the normal production of thyroid hormones and normal thyroid function. The separate wording “iodine contributes to the normal growth of children” is an authorised children’s development claim under Article 14 of Regulation (EC) No 1924/2006, not a general 432/2012 claim.

The mechanism explains why the claim is worded around growth and cognition rather than energy or immunity. Iodine has essentially one job: it is a building block of the thyroid hormones T3 and T4. Those hormones then regulate growth, development and metabolic rate throughout the body — and in a developing brain they influence how neurons migrate into position and how nerve fibres are myelinated. The thyroid is the intermediary, which is why an iodine shortfall shows up as a thyroid problem first and everything else second.

At the population level this matters more than the small quantities suggest. In regions with chronic iodine deficiency, studies in mostly paediatric populations have associated it with mean IQ scores 7 to 13.5 points lower than in iodine-sufficient groups, and severe deficiency in pregnancy causes irreversible harm. That is a finding about populations lacking iodine, and it is worth being clear what it does not say: it is not evidence that adding iodine to a child who already gets enough improves cognition. No supplement may be sold on that basis, and this one is not.

Where iodine actually comes from, in numbers

Iodine is concentrated in a short list of foods, which is why intake swings so widely between households eating otherwise similar meals. Approximate amounts:

Read that table next to the age figures and the shape of the problem becomes obvious. A child who eats fish and dairy regularly clears 90 µg without anyone thinking about it. A child who eats neither can be a long way short, because almost nothing else on a typical plate carries meaningful iodine.

Two traps are worth naming. Iodised salt is a deliberate public-health measure, not a property of salt — sea salt, pink Himalayan and gourmet finishing salts are generally not iodised, so switching to them silently removes a source. And plant drinks are not dairy substitutes for iodine unless fortified: many are not, and organic versions often are not by policy. Because the quantities are micrograms, the label is more reliable than any judgement about how natural a food looks.

Seaweed is the opposite problem. Iodine content varies enormously between species and batches — kelp in particular can deliver many times a child’s daily requirement in a single serving — so it is an unreliable way to hit a target and an easy way to overshoot one.

Who may need closer attention?

Children who avoid fish and dairy, use only non-iodised salt, or follow a vegan diet without iodine-fortified foods may need closer planning. Thyroid disease changes the conversation: both too little and too much iodine can affect thyroid function, so a diagnosed thyroid condition deserves clinician guidance.

How Frank Fruities Kid’s Multi fits

With iodine, too much causes the same problems as too little

This is the part that surprises people, and it is the reason iodine deserves more care than most nutrients in a children’s supplement. Sustained excess iodine suppresses thyroid hormone production, so it can produce hypothyroidism and goitre — the same outcomes deficiency causes. More is not merely useless past a point; it bends back on itself. Iodine-induced goitre is documented in populations with very high seaweed intake.

The ceilings are age-banded and they are low in absolute terms:

For a three-year-old the gap between the target and the ceiling is roughly one portion of cod. That is not a reason for alarm at ordinary food intakes — it is a reason to count supplements rather than stack them. Kelp tablets, iodine drops and a second multivitamin are the realistic routes to a problem; fish and milk are not. Those figures are ceilings, not goals.

Frequently asked questions

How much iodine does a 5-year-old need?

Children aged 1–8 have an RDA of 90 µg of iodine a day.

Is sea salt naturally iodised?

Not necessarily. Sea salt, pink salt and gourmet salt only count as dependable sources when the label says iodine has been added.

Do plant milks contain iodine?

Some are fortified and many are not. Check the nutrition and ingredient label rather than assuming.

What does iodine do for children?

Iodine supports normal thyroid-hormone production and cognitive function; an authorised Article 14 claim also states that iodine contributes to normal growth of children.

Can children get too much iodine?

Yes. High intakes can disrupt thyroid function, especially when drops, kelp and overlapping multivitamins are combined.

Why is 50 µg shown as 33% NRV?

The EU adult NRV is 150 µg. For ages 3–8, 50 µg is about 56% of the age-based RDA instead.

Which foods give children the most iodine?

White fish, dairy and eggs do most of the work. An 85 g portion of cod carries roughly 146 µg and a 240 ml glass of cow’s milk around 88 µg — either covers a young child’s daily reference on its own. Outside those foods and iodised salt, very little of a typical plate contains meaningful iodine.

Is seaweed a good way to give children iodine?

It is unpredictable. Iodine content varies enormously between seaweed species and batches, and kelp especially can supply many times a child’s daily requirement in one serving. That makes it an easy way to overshoot the upper limit rather than a dependable way to meet a target.

Does more iodine make children smarter?

No. Chronic iodine deficiency in a population is associated with lower mean IQ, which is why iodised salt programmes exist — but that is evidence about correcting a shortfall, not about adding iodine on top of enough. No supplement may be sold as improving a child’s intelligence, and extra iodine beyond requirements carries its own thyroid risk.