Iron Deficiency Anemia

Iron Deficiency Anemia

• Iron deficiency is the most common nutritional disorder worldwide, leading to clinical signs and symptoms related to inadequate hemoglobin synthesis.
• It is more prevalent in developing countries, but also common in the United States, particularly among toddlers, adolescent girls, and women of childbearing age.

Iron Metabolism

• The average Western diet contains 10-20 mg of iron daily, mostly in the form of heme in animal products and inorganic iron in vegetables.
• About 20% of heme iron is absorbable, while only 1-2% of nonheme iron is absorbable.
• The average Western diet provides sufficient iron to balance fixed daily losses.

Total Body Iron Content

• The total body iron content is approximately 2.5 gm in women and up to 6 gm in men.
• Iron is divided into functional and storage compartments.
• About 80% of functional iron is found in hemoglobin, with the rest in myoglobin, iron-containing enzymes, and other proteins.
• The storage pool, comprising hemosiderin and ferritin, contains about 15-20% of total body iron.

Iron Storage Sites

• The liver and mononuclear phagocytes are the major sites of iron storage.
• Healthy young females have smaller iron stores due to blood loss during menstruation, making them more prone to iron deficiency.

Iron Recycling and Transport

• Iron is recycled between functional and storage pools.
• Transferrin, a liver-synthesized iron-binding glycoprotein, transports iron in plasma.
• Transferrin is about one-third saturated with iron, yielding average serum iron levels of 120 µg/dL in men and 100 µg/dL in women.
• The primary function of plasma transferrin is to deliver iron to cells, including erythroid precursors, for hemoglobin synthesis.