What is the most common nutrient deficiency causing anemia in the United States?

• A. Iron deficiency
• B. Vitamin B12 deficiency
• C. Folate deficiency
• D. Vitamin C deficiency

Answer: (A)

Iron is needed to make hemoglobin, the protein that carries oxygen in red blood cells. When iron stores are low, hemoglobin synthesis falters, producing fewer and smaller red blood cells—a pattern called iron deficiency anemia. In the United States, this is the most common nutrient deficiency that leads to anemia, driven by menstrual losses and pregnancy in women of childbearing age, rapid growth in children, and sometimes blood loss from the gastrointestinal tract in older adults. Early lab clues include low ferritin reflecting depleted iron stores, with other typical findings being low serum iron, high total iron-binding capacity, and low transferrin saturation, often alongside microcytic, hypochromic red blood cells. This distinguishes it from deficiencies like vitamin B12 or folate, which cause macrocytic anemia, and from vitamin C deficiency, which is not a common cause of anemia.