Serial Phlebotomy in Voluntary Blood Donors

Inclusion Criteria: * hemoglobin levels \>13.5 g/dl for men, or \>12.5 g/dl for women * serum ferritin 50-400 ng/ml Exclusion Criteria: * known intolerance of phlebotomy procedures * major trauma or surgical procedures in the last 2 years * menstrual or other uterine bleeding in the last 2 years * chronic oral anticoagulation or dual antiplatelet therapy * chronic non-steroidal anti-inflammatory drug use * known history of hemochromatosis or other disorder of hematopoiesis or Fe metabolism * chronic oral Fe supplementation other than Fe-containing multivitamins * history of active cancer in the past 2 years * known history of chronic inflammatory disease * uncontrolled hypertension * electrocardiographic evidence of prior myocardial infarction * diabetes mellitus * fasting glucose \>100 mg/dL * body mass index \>40 kg/m2 * any tobacco use in the past 6 months