Anemia: What is it?
Anemia is a common health problem characterized by a lack of red blood cells or hemoglobin. The main symptoms of anemia are fatigue, paleness and breathlessness increased effort.
Those most affected by anemia are women who have heavy periods, people who eat poorly, infants and young children. According to the World Health Organization, approximately 25% of world population suffers from anémie1.
Symptoms of anemia due to depletion of tissue oxygen. Red blood cells are cells found in blood. They contain mostly hemoglobin. Hemoglobin is composed of protein (globin) and a pigment (heme) that gives red blood. The fixed iron pigment that transports oxygen from the lungs to the cells. Oxygen is essential for cells that produce energy. The pigment bound to oxygen is colored red vermilion: the arterial blood. Hemoglobin also transports carbon dioxide from cells into the lungs. It becomes purplish red: the venous blood.
Causes
Anemia can be of various origins:
* Anything that decreases the production of red blood cells (such as kidney disease or a deficiency of iron or certain vitamins) or accelerates the pace of destruction;
* Bleeding, that is to say, a significant loss of blood outside the circulatory system. Blood loss may occur acutely, then a short period of time, or chronic, with small losses over a long period.
The kidneys secrete a hormone that induces the stem cells from bone marrow to generate new red blood cells: erythropoietin. Once produced, the new cells circulate in the blood during 120 days. Thus, each day, about 1% of red blood cells are renewed. Their destruction has mostly held in the spleen. Some components of red blood cells, including iron, are recycled to produce new ones.
Main types of anemia
* Iron deficiency anemia. This form of anemia most common. The heavy periods and a diet low in iron are the most common causes in women. Blood loss through the digestive tract is another common cause of this anemia. Iron deficiency anemia affects the size of red blood cells, which become smaller than normal (microcytic anemia). To learn more, read our fact sheet iron deficiency anemia.
* Anemia caused by vitamin deficiency. This type of anemia produces deformed red blood cells and very large (macrocytic anemia). The most common are those caused by a deficiency in vitamin B12 or vitamin B9 (folic acid). The former may occur because of inadequate dietary intake of this vitamin, its poor absorption in the intestines or a disease called pernicious anemia. For more details, see our handout anemia B12 deficiency.
* Anemia caused by chronic illness. Many chronic diseases (and sometimes their treatment) can reduce the production of red blood cells. This is the case of cancer, Crohn’s disease and inflammatory diseases such as rheumatoid arthritis. Kidney failure can also cause anemia because the kidneys produce erythropoietin, the hormone that stimulates red blood cell production. They still retain their size and look normal (normocytic anemia).
* Hemorrhagic Anemia. Blood loss can cause anemia. Heavy periods, childbirth or loss of blood in the stool (often invisible) due to gastro-intestinal problems (peptic ulcer, colon polyps or colorectal cancer).
* Hemolytic anemia. This type of anemia is characterized by a too rapid destruction of red blood cells. It may be due to an immune system (autoimmune or allergic), presence of toxins in the blood, infections (eg malaria), or be congenital (sickle cell anemia, thalassemia, etc..). The congenital form affects mostly people of African descent.
* Sideroblastic anemia. The term umbrella group of very rare anemia where red blood cells can not set the iron in hemoglobin. This is a problem enzymatic hereditary or acquired. Red blood cells are smaller than normal.
* Aplastic Anemia (or aplastic). This rare condition occurs when bone marrow stops producing enough blood stem cells. Thus, it is not only a lack of red blood cells, but also white blood cells and platelets. In 50% of cases, aplastic anemia is caused by toxins, certain drugs or exposure to radiation. It can also be explained by serious diseases such as leukemia.
Tags: Anemia, fatigue, hemoglobin, hormone, Iron deficiency, vitamin
