Red blood cells are responsible for carrying oxygen to every cell in the human body. Hemoglobin is the part of the red blood cell that has the capacity to carry oxygen, and every hemoglobin protein requires an iron at its core to accomplish this oxygen carrying feat. When iron levels are low, the oxygen carrying capacity of the blood decreases, and the body becomes systemically depleted of oxygen. This lack of oxygen causes the brain, muscles and even organs to slow down and not function optimally. Common symptoms of anemia include feelings of weakness and fatigue, headaches, difficulty concentrating and immune system suppression. Low iron levels can be caused by poor diet, malabsorption, significant blood loss and pregnancy. Mineral-rich herbs provide the body with high levels of iron that are easily absorbable.