Deficiency of iron in the diet leads to which hematologic reduction in iron deficiency anemia?

• A. Plasma
• B. WBCs
• C. Hemoglobin
• D. Antibodies

Answer: (C)

Iron is needed to form heme, the part of hemoglobin that carries oxygen. When dietary iron is lacking, the body can’t synthesize as much heme, so hemoglobin production drops. This leads to a lower hemoglobin level in the blood—the defining feature of iron deficiency anemia. The red blood cells also become smaller and paler (microcytic, hypochromic), but the key hematologic change is the decrease in hemoglobin. Plasma volume, white blood cell counts, and antibodies aren’t inherently reduced by iron deficiency in the same way.