A normal person needs about 20~25mg of iron per day, most of which comes from the iron released by the destruction of aging red blood cells. A daily intake of 1~1.5mg of iron from food is sufficient to maintain the balance of iron in the body (pregnant and breastfeeding women need 2~4mg). Most foods contain iron, with seaweed, hairy vegetables, nori, fungus, mushrooms, and animal liver, meat and blood rich in iron. The human body is not generally deficient in iron, but only in cases of increased need, insufficient iron intake or chronic blood loss can lead to iron deficiency. These include: 1. Increased needs of women of childbearing age, infants, and children and adolescents during growth and development. If the iron content in food is insufficient or poorly absorbed, iron deficiency can easily occur. 2, certain drugs, long-term large amounts of strong tea or stomach, duodenal disease can affect the absorption of iron. 3, chronic blood loss in the digestive tract, women with excessive menstruation cause iron deficiency.