Which infants is at greatest risk for iron deficiency anemia?

• A. 4 month-old term infant exclusively fed human milk
• B. 4 month-corrected gestational age, former preemie on transitional formula
• C. 10 month-old switched from formula to whole milk
• D. 17 month-old picky eater

Answer: (C)

Introducing cow’s milk before 1 year is a major risk for iron deficiency anemia in infants. Cow’s milk provides little iron and can also cause small amounts of intestinal blood loss, which together reduce iron intake and increase iron loss during a critical period when iron stores are depleting and dietary iron is needed. The infant who has recently switched to whole milk at 10 months is at greatest risk because this change occurs well before 12 months and displaces iron-rich foods, making iron deficiency more likely. In contrast, a term infant on human milk is still within a window where iron intake can be managed with complementary iron-rich foods; a former preemie on iron-fortified transitional formula continues to receive adequate, iron-containing nutrition; and a 17-month-old with limited foods may risk deficient intake, but the pre‑12‑month introduction of cow’s milk represents the strongest, most direct risk factor.