What Causes Iron-Deficiency Anemia?

Not having enough iron in your body causes iron-deficiency anemia. Lack of iron usually is due to blood loss, poor diet, or an inability to absorb enough iron from the foods you eat.

Blood Loss

When you lose blood, you lose iron. If you don’t have enough iron stored in your body to make up for the iron loss, you’ll develop iron-deficiency anemia.

In women, low iron levels may be due to blood loss from long or heavy menstrual periods or bleeding fibroids in the uterus. Blood loss that occurs during childbirth is another cause for low iron levels in women.

Internal bleeding (bleeding inside the body) also may lead to iron-deficiency anemia. This type of blood loss isn’t always obvious, and it may occur slowly. Some causes of internal bleeding are:

• A bleeding ulcer, colon polyp, or colon cancer
• Regular use of aspirin or other pain medicines, such as nonsteroidal anti-inflammatory drugs (for example, ibuprofen and naproxen)
• Urinary tract bleeding

Blood loss from severe injuries, surgery, or frequent blood drawings also can cause iron-deficiency anemia.

Poor Diet

The best sources of iron are meat, poultry, fish, eggs, and iron-fortified foods (foods that have iron added). If you don’t eat these foods regularly, or if you don’t take an iron supplement, you’re more likely to get iron-deficiency anemia.

Vegetarian diets can provide enough iron if the right foods are eaten. For example, good nonmeat sources of iron include spinach and other dark green leafy vegetables, certain types of beans, dried fruits, and iron-fortified breads and cereals.

During some stages of life, such as pregnancy and childhood, it may be hard to get enough iron in your diet. This is because your need for iron increases during these times of growth and development.

Inability To Absorb Enough Iron

Even if there's enough iron in your diet, your body may not be able to absorb it. This may be due to intestinal surgery or diseases of the intestine, such as Crohn’s disease or celiac disease.

Prescription medicines that reduce acid in the stomach also can interfere with iron absorption.