Introduction

Anemia occurs when your blood does not have enough red blood cells to properly carry oxygen to your organs and tissues. Because your body doesn't get enough oxygen, you feel tired -- one of the primary symptoms of anemia.

Your blood contains three types of cells -- white blood cells, which fight off infection; platelets, which help blood to clot; and red blood cells, which carry oxygen from your lungs throughout your body. Red blood cells are produced in your bone marrow and contain hemoglobin, an iron-based protein that helps blood cells carry oxygen. With anemia, your body either doesn't produce enough red blood cells or loses them faster than they can be replaced.

There are several types of anemia. The most common type is iron deficiency anemia, caused by a lack of iron in your body. Other types include:

• Vitamin deficiency anemia, megaloblastic anemia -- caused by a lack of folic acid and vitamin B12 in your body.
• Anemia of chronic disease -- caused when certain chronic diseases (such as cancer, kidney failure, or Crohn's disease) interfere with the production of red blood cells.
• Aplastic anemia -- caused when bone marrow loses its ability to produce all three types of blood cells. Aplastic anemia is life threatening.
• Hemolytic anemias -- caused when red blood cells are destroyed faster than the bone marrow can replace them.
• Sickle cell anemia -- caused by a defective type of hemoglobin that makes red blood cells assume a crescent or sickle shape. These sickle cells die early, meaning the body is always short of red blood cells, and can block blood flow through small vessels, causing pain. Sickle cell anemia is an inherited condition that affects mainly people of African, Mediterranean, Arabic, or South American descent.

The above information is based upon medical literature made available to Adam, (ii) is not intended to be used as a source of medical advice, and (iii) is not intended to be relied upon by any person or entity for purposes of medical diagnosis or treatment, and that Adam is not responsible for the decisions of Users relating to their use of the License Content (including, without limitation, a User's decision to seek or not to seek professional medical care or a specific treatment based upon the Licensed Content).