Almost everyone knows that our blood carries oxygen to all parts of the human body, from the toes to the brain. We don’t think about how the red blood cell knows which part of the body needs oxygen and how it drops the oxygen off at the right part and not lose it along the way.
Iron sits in the center of a ringlike structure called heme. This ring allows iron to bind to oxygen reversibly; it can grab the oxygen from the lungs and let it go at the oxygen-starved tissue. Each little red blood cell contains millions of hemoglobin rings, and each ring holds four iron atoms. These 4 iron atoms are bound to oxygen. Each red cell full of hemoglobin rings acts like a magnet that latches on to the iron/oxygen and when it gets to the place in need the “magnet” turns off and the oxygen is delivered. The question is how it knows where to take the oxygen and how it doesn’t drop some along the way and in so doing releasing unnecessary iron. Being released when not needed could build up toxic levels of iron. The delivery system must be perfect. Just like Goldilocks it must be “just right”.
Children need a steady supply of iron as they grow, especially during periods of rapid growth like infants and adolescents. Without enough iron they can’t make enough red cells to carry the oxygen. They may become pale, cranky, tired and weak. They may act out at home and struggle in school. More severe iron deficiency may also cause cravings or chewing of nonfood items such as ice, dirt or paper. Iron is critical for brain development particularly in early life and low iron has been linked to delays in thinking skills, attention problems, and behavior concerns.
Periods of fast growth, such as toddlers, demand lots of iron. 15% of toddlers in the US show signs of iron deficiency. Growth spurts occur into the late teen years and females have increase demands with monthly periods. One in ten adolescent females show signs of iron deficiency. Other conditions can lead to anemia such as inflammatory bowel disease and some bleeding disorders. Children over one year should drink no more than 24 ounces of cow’s milk d day.
Prevention is possible at key ages. In infants, delayed umbilical clamping for 30-60 seconds allows more iron-rich placental blood to pass from the mother to the infant. Iron supplements for preemies at about 2 months and for breast fed babies starting at about 6 months. Adding iron rich foods at 6 months helps.
Examples of iron rich foods are seafoods such as clams, oysters and sardines, lean beef, lamb and dark meat turkey, eggs from chicken/ducks, lentils, chickpeas, tofu, spinach, kale, broccoli and Swiss chard, iron fortified cereal, raisins and other dried fruits.
Iron deficiency is one health problem that is usually easy to fix. Remember too much iron is toxic. Follow doctor’s advice to get it “just right”.
By Sally Robinson, MD
Keeping Kids Healthy
University of Texas Medical Branch (UTMB)
Published August 2026