The Essentiality of Elemental iron Iron is essential for healthy red blood cell hemoglobin levels. Red blood cell hemoglobin is essential for oxygen transport. Oxygen and glucose are absolutely essential for brain function. The topic of today’s review. I think iron metabolism, assimilation and transport is highly misunderstood. And the subject of great controversy. Here is why. Hemoglobin is the essence of red blood cell function. And you can see in figure 1, iron is the essential core of hemoglobin….