gen-define-iron-absorption-and-deficiency-and-give-one-short-wor-5c0b

Define iron absorption and deficiency and give one short worked example.

# Iron Absorption and Deficiency ## Iron Absorption **Definition:** Iron absorption is the process by which dietary iron is taken up from the intestinal lumen (primarily in the duodenum and upper jejunum) into the enterocytes and then transported into the bloodstream for use throughout the body. - **Two forms:** Heme iron (from meat, ~15-35% absorbed) and non-heme iron (from plants, ~2-20% absorbed) - **Regulated by:** Hepcidin (hormone), body iron stores, and erythropoietic demand - **Enhanced by:** Vitamin C, gastric acid, meat proteins - **Inhibited by:** Phytates, tannins (tea/coffee), calcium, antacids ## Iron Deficiency **Definition:** A condition where total body iron stores are reduced or depleted, leading to impaired hemoglobin synthesis and potentially resulting in anemia. It progresses through three stages: 1. Depleted iron stores (low ferritin) 2. Iron-deficient erythropoiesis (low serum iron, high TIBC) 3. Iron deficiency anemia (low hemoglobin) --- ## Worked Example **Case:** A 28-year-old vegetarian woman presents with fatigue and pallor. **Lab Results:** - Hemoglobin: 9.5 g/dL (normal: 12-16 g/dL) - Serum ferritin: 8 ng/mL (normal: 15-150 ng/mL) - MCV: 72 fL (normal: 80-100 fL) **Analysis:** - Low Hb = anemia - Low ferritin = depleted iron stores - Low MCV = microcytic (small RBCs) - **Diagnosis:** Iron deficiency anemia, likely due to inadequate dietary intake of bioavailable (heme) iron