What is the primary cause of iron-deficiency anemia?

The primary cause of iron-deficiency anemia is insufficient iron intake or absorption. Iron is a critical component of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. When there is not enough iron available, either due to inadequate dietary intake or the body's inability to absorb iron effectively from food, hemoglobin production is compromised, leading to a decrease in red blood cell production. This results in anemia, characterized by fatigue, weakness, and pallor due to reduced oxygen-carrying capacity.

Iron deficiency can occur for several reasons, such as a diet low in iron-rich foods, gastrointestinal conditions that impair absorption (like celiac disease or certain infections), blood loss through menstruation or gastrointestinal bleeding, and increased demand during periods like pregnancy and growth spurts.

In contrast, high levels of iron intake would lead to iron overload rather than deficiency, excessive red blood cell production typically relates to conditions such as polycythemia, and vitamin B12 deficiency is associated with a different type of anemia called megaloblastic anemia, which is distinct from iron-deficiency anemia.