Definition of Iron deficiency anemia:

Anemia is a condition in which the body does not have enough healthy red blood cells. Iron is an important building block for red blood cells.

When your body does not have enough iron, it will make fewer red blood cells or red blood cells that are too small. This is called iron deficiency anemia.

See also:

• Anemia
• Iron deficiency anemia - children

Causes, incidence, and risk factors:

Iron deficiency anemia is the most common form of anemia.

Red blood cells bring oxygen to the body's tissues. Healthy red blood cells are made in your bone marrow. Red blood cells move through your body for 3 to 4 months. Parts of your body then remove old blood cells.

Iron is a key part of red blood cells. Without iron, the blood cannot carry oxygen effectively. Your body normally gets iron through your diet and by re-using iron from old red blood cells.

You get iron deficiency anemia when your body's iron stores run low. You can get iron deficiency if:

• You lose more blood cells and iron than your body can replace
• Your body does not do a good job of absorbing iron
• Your body is able to absorb iron, but you are not eating enough foods with iron in them
• Your body needs more iron than normal (such as if you are pregnant or breastfeeding)

Iron loss can be due to bleeding. Common causes of bleeding are:

• Heavy, long, or frequent menstrual periods
• Cancer in the esophagus, stomach, or colon
• Esophageal varices
• The use of aspirin, ibuprofen, or arthritis medicines for a long time
• Peptic ulcer disease

The body may not absorb enough iron in the diet due to:

• Celiac disease
• Crohn's disease
• Gastric bypass surgery
• Taking too many antacids that contain calcium

You may not get enough iron in the diet if:

• You are a strict vegetarian
• You are an older adult and do not eat a full diet