How to recognize and prevent iron deficiency in children
TL;DR
Iron deficiency is globally the most widespread nutrient deficiency in children. Signs include fatigue, paleness, and difficulty concentrating. The main dietary sources are red meat, liver, lentils, and kale — and vitamin C helps the body absorb iron from plant sources.
Iron is one of the nutrients parents hear most about — and for good reason. According to WHO, over 40% of children under 5 worldwide suffer from anemia, and iron deficiency is the most common cause. In Denmark, the situation is better, but iron deficiency still occurs — especially in infants aged 6-24 months and teenage girls with heavy menstruation. Early detection and an iron-rich diet can correct the situation — without it needing to be complicated.
What does iron do in the body?
Iron is indispensable for hemoglobin — the protein that carries oxygen from the lungs to all the body's cells. Without enough iron, the body simply does not get enough oxygen.
Iron has two central functions in the body:
- Oxygen carrier in the blood — hemoglobin in red blood cells contains iron and transports oxygen
- Brain development — iron is crucial for myelination of nerve pathways, especially in the first 3 years of life
Iron is also used in muscle myoglobin (oxygen storage) and in a wide range of enzyme systems. A child lacking iron not only loses energy — they also risk delayed cognitive development, as a study published in Nutrients documents can have long-lasting effects on learning ability.
What are signs of iron deficiency in children?
Iron deficiency develops gradually — and symptoms are diffuse at first. Many parents do not notice it until a routine blood test shows low hemoglobin.
Typical signs to look for:
- Unusual fatigue and lack of energy — the child is more tired than normal for their age
- Paleness — especially visible in the face, inside the eyelids, and nails
- Difficulty concentrating — trouble maintaining attention at school
- Frequent infections — the immune system is weakened by iron deficiency
- Loss of appetite — iron deficiency can paradoxically reduce the desire to eat
- Pica — craving to eat non-food items (soil, clay, ice) seen in severe iron deficiency
- Rapid shortness of breath during activity — in more severe anemia
Who is at greatest risk of iron deficiency?
Infants 6-24 months and teenage girls with heavy menstruation are the two major risk groups in Denmark. Early introduction of iron-rich solid food is crucial for infants.
Iron needs are relatively greatest in the youngest because growth is rapid and iron stores from fetal life are quickly depleted:
- Infants 6-24 months — breast milk alone does not cover iron needs after 6 months. Iron-rich solid food is necessary.
- Premature infants — have lower iron stores at birth and are especially vulnerable
- Teenage girls — menstruation significantly increases iron needs from puberty
- Children on a vegan diet — plant-based iron (non-heme) is absorbed less well than iron from meat
- Picky eaters — typically avoid the richest iron foods (red meat, liver, beans)
The best iron-rich foods for children
Heme iron from meat is absorbed 2-3 times better than non-heme iron from plants. Eat vitamin C-rich foods with plant-based iron sources to significantly increase absorption.
Iron content in selected foods (per 100 g):
- Liver (beef/chicken) — 6-10 mg iron. The absolute richest source. Max once a week for children due to vitamin A.
- Red meat (beef, lamb) — 2-3 mg iron. Heme iron with high bioavailability.
- Kale — 1.5 mg iron. Combine with lemon juice for better absorption.
- Lentils (cooked) — 3.3 mg iron. Excellent plant-based source.
- Kidney beans (cooked) — 2.2 mg iron. Popular in chili and tacos.
- Tofu (firm) — 2.7 mg iron. Easy to integrate into wok dishes and soups.
- Sesame seeds and tahini — 9.3 mg per 100 g. Use in dressings and hummus.
- Dark chocolate (70%+) — 3.3 mg iron. Easy to eat as a treat.
Want your child to help make iron-rich meals? Try making hummus with tahini and lentil soup together — both are iron-rich and popular with children. Find tools for this in MINI Family's kitchen set.
What promotes and inhibits iron absorption?
Vitamin C can increase the absorption of non-heme iron by up to 300%. Coffee, tea, and calcium from dairy products inhibit absorption — avoid them close to iron-rich meals.
Increases iron absorption:
- Vitamin C (orange, bell pepper, broccoli, strawberries)
- Heme iron from meat eaten with plant-based iron sources
- Fermentation and sourdough (reduce phytates in grains)
Inhibits iron absorption:
- Tea and coffee — tannins bind iron. Do not give tea to children under 1 year.
- Calcium — large amounts of milk with iron-rich meals reduce absorption
- Phytates in whole grains and legumes — soaking and boiling reduce them
When should you see a doctor?
If in doubt, contact your general practitioner. A simple blood test can measure hemoglobin and ferritin (iron stores) and provide a clear answer.
See a doctor if your child shows signs of iron deficiency combined with: marked paleness, severe fatigue affecting daily life, delayed motor or cognitive development, or if the child belongs to a risk group. The Danish Health Authority recommends that the health visitor assesses iron status in infants during scheduled home visits. Iron deficiency is treated with dietary changes and possibly iron supplements under medical supervision. See also our inspiration blog for recipes with iron-rich ingredients.
Iron deficiency in children is a real but preventable problem. With a varied diet that includes iron-rich foods — and vitamin C for plant-based sources — the risk is low. Infants after 6 months and teenage girls are the groups that require the most attention.
If in doubt, talk to your doctor. A blood test gives answers within a few days — and an iron-rich diet can show visible results after 4-6 weeks.
Frequently Asked Questions
When do infants start needing iron from food?
From 6 months. Breast milk and formula cover iron needs for the first 6 months, but after that the innate iron stores are quickly depleted. Introduce iron-rich foods early: meat puree, lentils, pureed beans, and iron-fortified porridge are good starting options.
Can I give my child iron supplements without consulting a doctor?
It is not recommended. Too much iron is harmful and can cause constipation, nausea, and in severe cases organ damage. Iron supplements for children should always be given under medical supervision based on a blood test.
Can a vegetarian child get enough iron?
Yes — but it requires conscious planning. Serve iron-rich plant sources (lentils, beans, tofu, kale, sesame seeds) regularly and always combine with vitamin C. Vegetarian children should have their iron status checked by blood test, especially in the first years of life.
Can children eat liver to get iron?
Yes, liver is the richest source of iron available. But due to its very high vitamin A content, it is recommended to limit it to a maximum of once a week for children. Beef, chicken, and fish are good daily alternatives.
Does milk worsen iron deficiency?
Large amounts of milk (over 500 ml/day) can contribute to iron deficiency in children, partly because calcium inhibits iron absorption and partly because milk fills without providing iron. Limit milk to 350-500 ml daily and ensure iron-rich meals.