Anemia is a condition in which the blood becomes deficient in red blood cells (RBC) or the hemoglobin portion of red blood cells. Hemoglobin is a protein responsible for transporting oxygen in our blood. The molecule is composed of an iron atom bound to a heme group. When iron levels are low, this molecule cannot function properly. Iron deficiency is the most common nutrient deficiency in North America. It is often caused by lack of iron in the diet, diminished iron absorption, increased iron requirement, blood loss or a combination of factors. It is essential to understand the underlying cause of anemia to treat it properly.