In which foods is iron found?

Last autumn, my son was constantly exhausted. Not just tired — foggy-brained, dragging through homework, pale around the mouth. Our GP ran a blood test. Low ferritin. She said she sees it every week, especially in children who’ve gone through a growth spurt or eat narrowly.

The most common signs of iron deficiency in children are persistent tiredness, pallor, reduced concentration, and recurrent infections. If you’re seeing a cluster of these over two to three weeks, it’s worth getting a ferritin blood test — ferritin, specifically, not just a general blood count.

Quick reference: Signs of iron deficiency in children

  • Persistent tiredness or low energy — not explained by sleep
  • Pallor — pale skin, pale inner lower eyelids, pale lips
  • Difficulty concentrating or following instructions at school
  • Recurrent infections — more colds or illnesses than usual
  • Pica cravings — eating ice, soil or chalk (pagophagia is specifically linked to iron deficiency)
  • Unusual irritability or mood changes without clear cause 

Why Iron Matters More Than Most Parents Realise

Iron isn’t just about energy. It’s doing work at a cellular level that most people don’t think about until something goes wrong.

There’s formal EU-level recognition of what iron actually does — and it’s more precise than the vague messaging you tend to see. Under Regulation (EC) No 1924/2006, the European Food Safety Authority has assessed and authorised the following: iron contributes to normal cognitive development, to the normal function of the immune system, to normal formation of red blood cells and haemoglobin, and to a reduction in tiredness and fatigue. These aren’t marketing phrases. They’re scientific standards based on clinical evidence — and they apply to children specifically.

Haemoglobin. Immune cells. Brain function. Iron is doing all of this simultaneously in a growing child’s body. When intake falls short, the effects aren’t always immediate or obvious. That’s part of what makes deficiency easy to miss.

The Signs to Watch For

You might not see all of these at once. In fact, most children with low iron present with just two or three signs — which is exactly why it can look like a string of unrelated things rather than one underlying cause.

Persistent tiredness is the most common sign, and also the most dismissed. You might notice your child needing to rest during activities they’d normally take in their stride — after school, during sport, or by mid-afternoon. It’s different from ordinary tiredness. It’s there on weekends too.

Pallor is more diagnostic than most parents expect. The most reliable place to check isn’t the cheeks — it’s the inner lower eyelids and the lips. Pull the lower eyelid down gently: in iron-sufficient children it’s pink or red inside; in children with lower haemoglobin, it tends to be pale or almost white. Worth noting that pallor is more indicative when haemoglobin itself is low, not just ferritin, so this sign appears at a more advanced stage.

Difficulty concentrating or tracking at school is often the sign that gets attributed to everything else first. Attention issues. Too much screen time. Boredom. But iron contributes to normal cognitive development — and when it’s short, the brain is literally under-resourced. If concentration has changed and there’s no obvious external explanation, iron is worth ruling out.

Recurrent infections — not just one cold, but one thing after another from September to March — can sometimes reflect low iron status. The immune connection is real: iron contributes to the normal function of the immune system, and deficient children can show increased susceptibility to respiratory infections in particular.

Pica — the craving to eat non-food substances — and specifically pagophagia, the craving to chew or eat ice, is specifically and strongly associated with iron deficiency. It’s not the same as a child liking cold drinks. It’s compulsive. If your child is crunching ice compulsively or putting unusual non-food items in their mouth, get a ferritin test. Don’t wait.

A cluster of two or more of these signs, persisting over two to three weeks, is the practical signal to act on. One sign alone, briefly, probably isn’t iron deficiency. A pattern is. 

The Iron in Food — and Why It’s More Complicated Than It Looks

Not all dietary iron is absorbed equally. This is the part that surprises most parents.

Haem iron — found in meat, poultry and fish — is absorbed at a rate of roughly 15–35%. Non-haem iron — found in plants, legumes, fortified cereals and eggs — is absorbed at 2–20%, and significantly affected by what else is in the meal. The practical implication: a serving of lentils does not deliver the same usable iron as a serving of beef mince, even if the labels show similar mg values. 

Animal sources (haem iron — higher absorption)

Beef and lamb are the most concentrated sources: roughly 2.5–3.5 mg per 100g, well-absorbed. Chicken liver is exceptional — around 12 mg per 100g — but limit to once a week due to high vitamin A content. Sardines, tuna and mackerel provide meaningful iron alongside DHA. Eggs contribute around 1.2 mg per egg, from the yolk specifically.

Plant sources (non-haem iron — lower absorption but important)

Lentils (around 3.3 mg per 100g cooked), chickpeas, kidney beans, tofu, spinach, kale, pumpkin seeds, fortified breakfast cereals. These are valuable, particularly for vegetarian or vegan children, but their iron yield depends heavily on what’s consumed alongside them.

The vitamin C trick is real — and it’s simple. Consuming vitamin C-rich food in the same meal as plant-based iron increases absorption significantly. Orange juice with fortified cereal. Bell peppers with lentil soup. Strawberries with a chickpea salad. This applies to food-based vitamin C. High-dose vitamin C supplements used alongside iron supplements are a different matter and should be discussed with a doctor.

On the other side: tea and coffee reduce iron absorption when consumed close to an iron-rich meal. The polyphenols bind iron and prevent uptake. Leave at least 1–2 hours between an iron-rich meal and tea or coffee. Calcium-rich foods — including dairy — have a similar effect when consumed simultaneously. This matters for children who drink milk with meals and then struggle to absorb the iron from the same plate.

Getting a 6-year-old to eat lentils three times a week is its own Olympic sport. We know. But knowing which combinations work — even occasionally — is genuinely useful.

Cast iron cookware is worth a brief mention: cooking acidic foods like tomato sauce in cast iron transfers small amounts of iron to the food. The clinical relevance is modest, but it’s a zero-effort addition if you already use cast iron.

What about seasons? In Belgium and the Netherlands, winter months often see a natural reduction in fresh fruit and vegetable variety — which can reduce vitamin C intake and therefore reduce the conversion of dietary non-haem iron. This isn’t catastrophic, but it’s a real seasonal factor worth being aware of.

Why Food Alone Often Isn’t Enough

Here’s the uncomfortable truth: even children eating a broadly healthy diet often don’t reach the recommended iron intake.

EFSA’s reference intake for iron is 7 mg/day for children aged 1–6, and 11 mg/day for children aged 7–11. For vegetarian or vegan children, requirements are approximately 1.8 times higher because of the lower bioavailability of non-haem iron. Meeting these figures from diet alone requires consistent, varied, well-paired food choices — which is harder to achieve day-to-day with a real child than it looks on a nutritional planning sheet.

Rapid growth phases — between ages 1–3 and again around 9–12 — increase iron demand significantly. Children coming out of an illness may also have depleted stores. If your child falls into one of these categories and eats narrowly, dietary intake probably isn’t keeping pace. 

What You Can Do Today

Three things. None of them involve buying anything.

First: identify the best iron sources already in your child’s regular diet and make sure they’re there most days. Eggs at breakfast. A lentil or chickpea dish once or twice a week. Red meat or sardines once a week if they’re eaten. These aren’t dramatic changes — they’re small consistent shifts that compound over weeks. 

Second: pair iron-containing meals with vitamin C. Orange juice with breakfast cereal. A small glass of tomato juice with lunch. Bell peppers chopped into whatever’s on the plate. This is a habit, not a strict protocol — even four or five times a week makes a meaningful difference to non-haem iron absorption.

Third: keep a two-week symptom log. This is the most underused tool parents have. What a useful log entry looks like: ‘Monday — visibly tired after school, didn’t finish homework, pale inner eyelid on check. Iron-rich meal: no.’ A vague log entry: ‘Still tired this week.’ The specific one gives a GP something to work with. The vague one doesn’t.

When to Contact Your Doctor

Don’t wait for a long list of symptoms to stack up before you ask. Contact your GP if two or more signs are present and persisting for two to three weeks; if your child is a selective eater and avoids most of the iron-rich food categories; if they’re vegan or vegetarian without a deliberate plan for iron intake; if they’re in a rapid growth phase and seem unusually fatigued; if they’ve had a prolonged illness in the past month; or if you’re observing pica behaviour — any craving for non-food items, especially ice.

Ask specifically for a ferritin test, not just a full blood count. Ferritin drops before haemoglobin does — it’s the earlier and more sensitive marker of iron status. Many GPs will run haemoglobin by default; you may need to ask for ferritin by name.

If supplementation is started, recheck ferritin after 8–12 weeks to confirm it’s recovering. More iron is not better once ferritin is normal — over-supplementation carries its own risks.

When a Supplement Makes Sense

If your child’s ferritin comes back normal, do not supplement with iron. This point isn’t emphasised enough. Iron supplementation when ferritin is adequate provides no benefit and may cause harm.

If a supplement is indicated — either because ferritin is low or because a healthcare professional has recommended it — the form matters. Iron drops, chewables and syrups all have their place. Tolerability varies significantly between forms: traditional ferrous sulphate is associated with gastrointestinal side effects in some children, including nausea and constipation, which can make consistent use difficult.

One option that’s been formulated with tolerability in mind is Fisher Kinder Iron Syrup, which uses liposomal ferric pyrophosphate — a form of iron designed to be gentler on the digestive tract. It’s banana-flavoured, GMP-produced in France, and registered under NUT/PL 2441/125. In Belgian pharmacies, you’ll find it under CNK code 4733317. As with all iron supplements, dark stools are normal and expected — worth knowing in advance so it doesn’t cause unnecessary concern. 

A Word on Safety — Read This Before You Start

Iron supplements are not the same as iron from food. The amounts in supplements are concentrated, and accidental overdose in children is a genuine medical risk — not a theoretical one. Iron poisoning is among the leading causes of accidental supplement-related death in young children.

Store iron supplements out of reach of children, in a locked cabinet if possible. Treat them the same way you’d treat prescription medicine.

If you suspect a child has ingested iron supplements — even if they seem fine — do not wait for symptoms. Contact Poison Control immediately. In Belgium: 070 245 245. In the Netherlands: 030 274 88 88. Symptoms of iron overdose can be delayed; acting immediately is the only right response.

Low iron in children is common, treatable, and often missed because the signs are quiet. The combination of a diet that’s mostly good but missing a few key pairs, seasonal factors, and a growth phase can get a child to a ferritin level that affects how they function at school and at home — without anyone connecting the dots. Knowing what to look for, when to test, and how to pair foods makes a real difference. The rest takes care of itself.

Food supplements are not a substitute for a varied and balanced diet and a healthy lifestyle. Always consult a qualified healthcare professional before starting any supplement.

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