The daily iron requirements vary based on age, sex, and physiological status. Men generally need 8 mg/day, while pre-menopausal women need 18 mg/day, pregnant women need 27 mg/day, and breastfeeding women need 9-10 mg/day. After menopause, women's iron requirements decrease. Iron is crucial for oxygen transport and enzyme function. It's important to meet daily requirements to prevent anemia and maintain overall health.