The Surprising Link Between Iron and Your Child’s Sleep

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When we think about helping kids sleep well, we usually focus on bedtime routines, an ideal sleep environment, or sticking to a schedule. But there’s one important piece that often gets missed: iron.

More and more research shows that low iron levels — especially something called iron deficiency anemia (IDA) — can affect how babies and young children sleep.

What Is Iron Deficiency Anemia?

Iron deficiency anemia happens when the body doesn’t have enough iron to make healthy red blood cells. It’s the most common nutrient deficiency in the world, and it affects about 1 in 4 babies.

This usually happens at a time when the brain is growing fast and the body needs lots of iron. Full-term babies are born with enough iron to last about 4–6 months. And while breast milk is rich in many nutrients, it contains very small amounts of iron. That’s why around 6 months, it’s important to start offering iron-rich complementary foods.

How Does Iron Affect Sleep?

Research from the University of Chile and the University of Michigan has shown that iron plays a key role in how little ones sleep. Here's what they found:

  • Sleep Brainwaves: Babies with IDA have fewer “sleep spindles” — special brainwaves that help with memory and body control. This means their brains might not be getting the same quality of sleep.

  • Sleep Patterns: These little ones often nap longer during the day, but sleep less soundly at night. They spend less time in deep, restful sleep, and may wake more often.

  • Restless Movement: Studies using motion trackers found that babies with IDA move around more in their sleep, wake up more during the night, and have less quiet, deep sleep — which can affect brain and emotional development.

In addition, iron helps to regulate melatonin and supports brain chemicals like dopamine and serotonin, both of which are important for sleep.

Long-Term Effects on Sleep

Even after their iron levels go back to normal, some kids who had IDA as babies still sleep differently years later:

  • REM Sleep Changes: At age four, kids who had IDA in infancy often have longer REM sleep early in the night and shorter REM later on. This throws off their natural sleep rhythm.

  • Less Deep Sleep: They may also spend less time in deep, restorative sleep, and their sleep cycles may still be a bit off.

Why This Matters

Good sleep helps kids learn, grow, and manage their emotions. When iron levels are low, it can lead to:

  • Moodiness or crankiness

  • Trouble paying attention

  • Hyperactivity

  • Learning delays or memory issues

  • Behavioural issues

Catching and treating low iron early can help improve sleep and support healthy development overall.

How to Keep Your Child’s Iron Levels Healthy

  1. Offer Iron-Rich Foods: Include foods like red meat, beans, lentils, spinach, and iron-fortified cereals. Pair them with foods high in vitamin C (like oranges or tomatoes) to help the body absorb the iron better. If your little one is over 12 months, try to keep milk to under 16–20 oz/day — too much can block iron absorption.

  2. Watch for Signs: Look for symptoms like tiredness, pale skin, poor appetite, restless sleep or irritability. If something feels off, check in with your child’s doctor.

  3. Use Supplements if Needed: If your child is diagnosed with low iron, your doctor may suggest a supplement. Don’t give iron supplements unless your healthcare provider recommends it — too much iron can be harmful.

Iron plays a critical role in your child’s growth, development, and even their ability to get a good night’s sleep. If your little one is experiencing sleep disturbances, it’s worth considering whether iron levels might be a contributing factor. Making sure your child gets enough iron can support better sleep, better mood, and healthy growth — now and in the years to come.

Disclaimer: This is not medical advice. Always check with your healthcare provider.

Reference
Peirano, P. D., Algarín, C. R., Chamorro, R. A., Reyes, S. C., Durán, S. A., Garrido, M. I., & Lozoff, B. (2010). Sleep alterations and iron deficiency anemia in infancy. Sleep Medicine, 11(7), 622–629. https://doi.org/10.1016/j.sleep.2010.03.014