Non-heme iron refers to a type of dietary iron that is not bound to heme, which is an organic molecule found in hemoglobin. Heme iron is derived from animal sources and is more easily absorbed by the body than non-heme iron, which comes mainly from plant sources such as leafy greens, beans, nuts, seeds, and fortified foods like cereals or bread. Non-heme iron is less bioavailable due to its chemical structure, but it still plays an important role in maintaining good health by contributing to overall iron levels in the body.