Kingnature Eisen Vida - contains 100 Vegi capsules with iron from a bioavailable source Our blood gets its typical red color from the protein hemoglobin (Hb). It is the most important component of red blood cells, also called the erythrocytes. The red blood cells have the task of transporting oxygen from the lungs to our body’s cells, where they remove harmful carbon dioxide as a metabolic waste product. This is where the blood pigment hemoglobin comes into play. Hemoglobin contains the trace element, iron, which binds oxygen and thus ensures its transport to the body’s cells. This is why iron is extremely important. The body cannot produce iron itself and must absorb it from the food we eat. The daily requirement is about one to three milligrams.