Iron is one of the most important nutrients your child needs to grow. It helps the body make hemoglobin, the part of red blood cells that carries oxygen from the lungs to the rest of the body.

A child can have low iron before becoming anemic. If the iron shortage progresses, the body may not make enough hemoglobin to carry oxygen normally. This is called iron-deficiency anemia.

The good news: iron deficiency can be checked with blood tests, is treatable, and can often be prevented with appropriate nutrition and supplements when recommended.

Why iron matters so much in childhood

Young children grow quickly, and their bodies need a steady supply of iron to keep up. Beyond making red blood cells, iron is important for brain development, energy, attention, and learning.

Getting enough iron during the early years supports how your child thinks, moves, and feels every day.

Who is most at risk?

Iron deficiency is common. Some children are more likely to develop it than others:

Babies born early or with a low birth weight, because they build up smaller iron stores before birth.
Babies given cow's milk as a drink before their first birthday, or children who drink too much milk. More than about 24 ounces, or 3 cups, per day can crowd out iron-rich foods. Cow's milk is a good source of calcium but has very little iron.
Breastfed babies who are not getting enough additional iron from iron-rich foods or a recommended supplement as they grow.
Picky eaters or children who eat few iron-rich foods.
Children on vegetarian or vegan diets without careful attention to iron intake.
Teens, especially those who menstruate, because of rapid growth and menstrual blood loss.
Children exposed to lead.

Signs to watch for

Many children with iron deficiency have no obvious symptoms at all. When symptoms do appear, they can include:

Looking pale or tired
Being more fussy, irritable, or fatigued than usual, with more naps or less interest in play
Trouble concentrating or paying attention
In more severe cases, shortness of breath, a fast heartbeat, dizziness, or fainting

One unusual sign is pica—craving or chewing non-food items such as ice, dirt, paper, or cardboard. If you notice this, mention it to your child's doctor.

These symptoms can have many causes. Attention difficulties or tiredness alone do not establish that a child has low iron.

How doctors check for it

The American Academy of Pediatrics' 2026 guidance recommends screening at ages when children are most at risk:

Babies fed mostly breast milk: around 9 to 12 months.
Babies fed mostly iron-fortified formula: around 15 to 18 months, after the transition away from infant formula.
Adolescents who menstruate: about a year after periods begin, but no later than age 14.

Children with ongoing risk factors may need repeat screening. Symptoms, heavy periods, or a low-iron diet may also prompt testing at other times.

The doctor may check a blood count and ferritin, a test that helps estimate the body's stored iron. A quick hemoglobin check alone can miss low iron before anemia develops.

A normal physical exam does not rule out low iron. Your child's clinician considers the blood tests together with symptoms, diet, growth, and medical history.

For a plain-language explanation of blood-test flags, see Understanding Your Child's Lab Results.

How it is treated

The main treatment is iron replacement, along with addressing the cause. For many young children, that includes changes to their diet. Food choices help, but diet changes alone may not be enough to treat iron-deficiency anemia.

Key points parents should know:

Ferrous sulfate is a commonly recommended first-choice iron supplement. It comes in liquid forms for young children and tablets for older children.
Iron is often prescribed once a day. Follow your child's specific instructions.
Iron is best absorbed on an empty stomach, but if it causes stomach upset, ask your clinician whether it can be given with a small amount of food.
Avoid giving iron at the same time as milk or calcium supplements; ask your clinician or pharmacist how to space them.
Vitamin C can help iron absorption, but a separate vitamin C supplement is not routinely required.
Give iron exactly as prescribed. Use the recommended measuring device for liquid medicine, and do not start or increase a treatment dose on your own.

Common side effects

Iron can cause stomach upset, nausea, constipation, or diarrhea. Contact your clinician if side effects are significant or make it difficult to continue treatment.

Dark stools are expected while taking iron. However, stools that look tarry, visible blood, or significant abdominal pain need prompt medical advice rather than being assumed to be a harmless side effect.

Liquid iron can temporarily stain the teeth. Give it slowly with an oral syringe aimed against the inside of the cheek, not toward the throat. Brushing afterward can help reduce staining.

Follow-up matters

Treatment often continues for at least 3 months, and sometimes longer, to rebuild iron stores. Your child will have follow-up blood tests, often around 1 month and 3 months, with timing adjusted to the severity of the anemia and response to treatment.

Your child may seem better before iron stores have recovered. Keep giving the supplement for the prescribed duration unless your clinician changes the plan.

Preventing low iron: everyday food choices

For most families, prevention includes a few practical eating habits:

Do not replace breast milk or infant formula with cow's milk before 12 months. After the first birthday, keep milk intake below 24 ounces, or 3 cups, per day. Discuss plant-based alternatives with your pediatrician because their nutritional content varies.
Offer iron-rich foods starting around 6 months, as your child is ready. Choose textures and sizes appropriate for your child's feeding skills.
Animal sources include beef, chicken, turkey, and fish.
Plant and fortified sources include iron-fortified infant cereals, beans, lentils, tofu, spinach, and iron-enriched breads and pastas.
Pair plant sources of iron with vitamin C foods such as strawberries, tomatoes, bell peppers, or oranges to help absorption.
Breastfed babies may need an iron supplement starting at 4 to 6 months. Ask your pediatrician about the right plan for your baby.
Premature babies often need extra iron earlier. Your baby's doctor will guide the timing and amount.

Moving from a bottle to a cup can make it easier to reduce excessive milk intake. Offer a variety of foods without pressure, and ask for help if your child is struggling with feeding or growth.

When to talk to your child's doctor

Reach out if your child:

Looks unusually pale, is very tired, or is more irritable than usual
Craves or eats non-food items such as ice, dirt, or paper
Drinks a large amount of milk and eats few other foods
Has heavy periods or another concern about ongoing blood loss
Is not improving with the prescribed treatment or cannot tolerate it

Seek prompt medical care for shortness of breath, a racing heart, dizziness, or fainting. Severe breathing difficulty, collapse, or difficulty waking needs emergency care. For a possible life-threatening emergency, call 911.

The bottom line

Low iron is common and treatable, and it can be present before anemia develops.

Iron-rich foods, appropriate milk intake, and screening at the right times help protect your child's health. If treatment is needed, give iron as directed and keep follow-up appointments—even when your child starts feeling better.

Your pediatrician can help you choose a plan that fits your child's age, diet, and test results.

Low Iron and Anemia in Children: What Parents Should Know