Anemia

2011 rev.
The College of Family Physicians of Canada

This information provides a general overview on this topic and may not apply to everyone. To find out if this information applies to you and to get more information on this subject, talk to your family doctor.

What is anemia?

Anemia is a condition that affects your red blood cells. It occurs when your blood doesn't have enough hemoglobin. Hemoglobin is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body. Anemia can starve your body of the oxygen it needs to survive.

Many things can lead to anemia. The most common cause is not having enough iron in your blood. Iron is a mineral the body needs to make hemoglobin. Anemia due to low iron levels is called iron deficiency anemia. Some people refer to anemia as "low blood".

Symptoms of anemia

  • Often there are no symptoms 
  • Paleness 
  • Feeling tired 
  • More shortness of breath during exercise 
  • Unusual food cravings (known as pica) 
  • Fast heartbeat 
  • Cold hands and feet 
  • Brittle nails or hair loss 
  • Headaches 
  • Dizziness or light-headedness 
  • Symptoms usually come on slowly so that you feel no sudden change in your energy level

What can lead to low iron levels in the blood?

A number of things can cause your blood to be low in iron.

Lack of iron in the diet. You may have low iron levels if you don’t eat enough foods high in iron. This is mostly a problem for children and young women. Small children who drink large amounts of milk and avoid iron-rich foods and young women who follow fad diets or are vegetarian may be at risk for low iron levels.

Growth spurts. Children under age three are growing so fast that their bodies may have a hard time keeping up with the amount of iron they need.

Pregnancy. Women who are pregnant or are breastfeeding need more iron. That's why pregnant women may be tested for anemia and why they need to eat more iron-rich foods or may need to take a daily iron pill.

Blood loss. This is the most common reason for iron deficiency anemia in adults. Women, of course, lose blood every month during their periods. Heavy periods may cause anemia.

Blood loss can also be caused by internal bleeding, usually in the digestive tract. A stomach ulcer, ulcerative colitis, cancer, or taking anti-inflammatory pills such as Ibuprofen or Aspirin for a long time can cause bleeding in your stomach or intestines. That's why it's so important to find the reason for a low iron level.

Inability to absorb iron. The iron in your food is absorbed by the body in the small intestine. Diseases that affect your small intestine’s ability to absorb nutrients, such as Crohn’s disease or celiac disease, may cause low iron levels in your body. Some foods or medicines, including milk, antacids or stomach acid-lowering medicines, also can prevent your body from absorbing iron.

How is anemia diagnosed?

Talk to your doctor if you think you might have anemia. Your doctor will order a blood test to diagnose anemia. Other tests may also be needed to find out what's causing the anemia.

How is anemia treated?

This depends on what's causing the anemia. For example, if anemia results from losing too much blood, the cause of the blood loss will need to be found and treated. If anemia results from a diet that's low in iron, your doctor may suggest that you change your diet or that you take iron pills to increase the amount of iron in your body.

Can anemia be prevented?

Some types can, such as those caused by a diet that lacks iron. You can help prevent this type of anemia by making sure you eat foods that contain iron. See the  list of iron-rich foods below.

Infants need to be started on cereal by ages 4 to 6 months and formulas should contain iron.

Foods high in iron:

  • Liver and red meat 
  • Seafood (sardines) 
  • Dried fruits like apricots, prunes, and raisins 
  • Nuts 
  • Beans, especially lima beans 
  • Green leafy vegetables, such as greens, parsley, spinach, and broccoli 
  • Black strap molasses 
  • Whole grains 
  • Iron fortified foods like many breads and cereals (check the label)

How can I increase how much iron I get from my diet?

Eat more foods that are high in iron (see the list above). Only a small amount of the iron in foods is absorbed, or taken in, by your body.

Your body best absorbs the iron in meats. Eating a small amount of meat along with other sources of iron, such as some vegetables, can help you get even more iron out of these foods. Taking high doses of vitamin C pills or eating foods high in vitamin C, such as citrus fruits or juice, at the same time you eat iron-rich foods or take your iron pill can also help your body absorb the iron.

Cooking in cast-iron pans will increase the iron content of food.

Some foods block the absorption of iron. These include coffee, tea, eggs, milk, fibre, and soy protein. Try to avoid them when you're eating foods high in iron.

Can iron pills cause problems?

Taking iron pills to try to prevent or treat anemia without first talking to your doctor may be harmful. Taking iron if you have anemia may make diagnosing anemia more difficult. It may also cover up a more serious disorder that could be causing the anemia.

Iron pills can also cause stomach upset, heartburn and constipation. Be sure to tell your doctor about any discomfort you notice. The tips below may help reduce this discomfort.

Tips on taking iron pills

  • Take the pills with food.
  • Start to take iron slowly. Try taking one pill a day for three to five days, then two pills a day until you aren't bothered by that amount. Increase the number of pills until you're taking the amount your doctor has recommended. 
  • Avoid taking calcium, zinc, copper supplement or multivitamins containing any of these minerals within 2 hours of taking iron pills. 
  • Avoid taking antacids within 2 hours of taking iron pills. 
  • Increase the fibre in your diet if you have constipation but also increase your water and fluid intake. This is worth trying even though fibre may get in the way of how well your body can absorb iron. You'll still be able to absorb some iron, and it's better than not taking any iron if you need it. 
  • Don't take iron pills at bedtime if they upset your stomach. 
  • If one type of iron pills causes problems, talk to your doctor about trying a different formula or brand. 
  • Store iron pills safely. Iron poisoning is a leading cause of accidental death in children. Iron pills often look like candy.

REFERENCES

  1. Bross MH, Soch K, Smith-Knuppel T. Anemia in older persons. Am Fam Physician. 2010 Sep 1;82(5):480-7.
  2. Janus J, Moerschel SK. Evaluation of anemia in children. Am Fam Physician. 2010 Jun 15;81(12):1462-71. Review.
  3. Killip S, Bennett JM, Chambers MD. Iron deficiency anemia. Am Fam Physician. 2007 Mar 1;75(5):671-8. Review. Erratum in: Am Fam Physician. 2008 Oct 15;78(8):914.
     


This health education material was developed and adapted by The College of Family Physicians of Canada from online materials developed by The American Academy of Family Physicians, with permission. It is regularly reviewed and updated by family physician members of the CFPC Patient Education Committee, who refer to the current evidence-based medical literature. Support for this program has been provided by a grant to the CFPC Research and Education Foundation by Scotiabank.

These pages may be reproduced for not-for-profit educational purposes only.

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