Information about Iron Supplements and Iron Deficiency

Many people worry about getting too little iron—for good reason. Iron, after all, is essential to life. Most iron in our bodies is incorporated in hemoglobin, which carries oxygen in the blood, and in myoglobin in muscle, but every living cell has and needs iron to function. Iron also stored in the liver, spleen, and bone marrow.

Without iron, your cells would become starved for oxygen, your brain and muscles wouldn't function and your immune system would be impaired, among other problems. But that doesn't mean most people need to take an iron supplement—or even a multivitamin/mineral pill that contains iron. So who needs an iron supplement?

Iron Deficiency Risk

Low iron intake over a long period can deplete iron stores—especially if your body is losing blood, as in menstruation. Early on in iron deficiency, there typically are no symptoms. As iron balance worsens, full-blown iron-deficiency anemia can develop, with symptoms such as

  • weakness
  • shortness of breath
  • paleness
  • poor appetite
  • poor learning and shortened attention span and
  • increased susceptibility to infection

A healthful diet usually provides ample iron, but some people are at risk for iron deficiency including:

  • Premenopausal women, especially those who bleed heavily during menstruation.
  • Pregnant women, who have higher iron needs because of the demands for increased blood production by the mother and the needs of the fetus and placenta.
  • Dieters, particularly premenopausal women—the less you eat, the less likely you are to get enough iron.
  • Long-distance runners and other endurance athletes, especially women and vegetarians. High-impact activities can cause destruction of red blood cells when the feet strike the ground.
  • Children and adolescents, who need more iron to support rapid growth; deficiencies may impair their learning capacity.
  • People taking proton pump inhibitors and H-2 blockers for reflux disease. These drugs reduce intestinal absorption of certain nutrients in the body, including iron.

Who Does Not Need an Iron Supplement?

The following people, in general, don't need supplemental iron—and may be better off without it:

  • Postmenopausal women. Data from the large Framingham study suggest that the low risk of heart disease among premenopausal women may not be due to hormones alone; it may also be attributable to menstruation and thus the monthly loss of iron. After menopause, when menstruation stops, women begin to catch up to men in heart disease risk. This suggests that higher iron stores may be a factor in the increasing rates of heart disease seen in postmenopausal women.
  • Men. Unless they have a condition that causes chronic blood loss, men don't need supplemental iron.

Iron Supplements: Dangerous for Some

People with hemochromatosis, in particular, should avoid excess iron. This hereditary disorder, which affects more than one million Americans (mostly of northern European descent), causes overabsorption and storage of iron. Left untreated, this leads to

  • weakness
  • headaches
  • darkening of skin
  • sexual dysfunction
  • joint pain, and eventually
  • diabetes, arthritis, liver disease, and/or heart failure

Get tested for hemochromatosis if you have a family history of it or develop symptoms that may be related to it. A simple blood test helps diagnose this condition. Many doctors recommend routine screening for hemochromatosis in middle age, especially for Caucasians. If you have the disorder, you must limit consumption of iron, especially heme iron (the kind found in meat), and avoid supplements. Donating blood regularly is commonly recommended.

About 10 to 15 percent of Americans carry only one gene for hemochromatosis (two genes, one from each parent, are needed to develop the full-blown disorder) and may accumulate slightly higher-than-average stores of iron. Other genes besides those involved in hemochromatosis can also result in iron overload.

What to Do if You Are in Need of More Iron

An iron-rich diet is especially important. Taking a multivitamin/mineral with 100% of the Daily Value for iron is a good idea, too. Your doctor may advise a separate higher iron supplement for a short time, but don't take high-dose iron on your own—certainly not just because you are tired and think you may be anemic. Weakness and fatigue can be symptoms of many other conditions, including anemia not caused by iron deficiency.

The iron in meat, poultry, and fish (heme iron) is best absorbed by the body. Legumes (dried beans, lentils, and peas), whole grains, nuts, and some vegetables also provide iron, but in a form (nonheme) that is less well absorbed. Consuming foods rich in vitamin C (such as citrus fruits and potatoes) at the same time as plant sources of iron boosts absorption of the iron. Cooking acidic foods, such as tomatoes, in iron pots adds iron to them. Enriched grains and fortified breakfast cereals are other iron sources.

Iron Tips

  • Don't worry about iron in food. It's hard to get too much iron through diet alone, unless you have hemochromatosis. Moreover, iron absorption in healthy people is well regulated, so absorption is very low if iron reserves are high, says Dr. Fernando Viteri, an iron expert and professor emeritus at the University of California, Berkeley. Still, be aware that if you eat a lot of iron-fortified foods, you may be getting more iron than you need. Some fortified breakfast cereals, for example, contain 100% of the Daily Value for iron.
  • Consume plenty of fruits and vegetables, which are high in antioxidants. Some researchers suggest that antioxidants may help counteract the action of iron-associated free radicals.
  • If you are a postmenopausal woman or a man and take a multivitamin/mineral pill, check the label for iron. Unless your doctor has told you that you are iron-deficient, look for one that has no iron. The iron is unnecessary. Many supplements marketed for men and older people do not contain iron.

Source: Originally published in The University of California, Berkeley Wellness Letter (February 2011)

Publication Review By: the Editorial Staff at

Published: 26 Apr 2011

Last Modified: 21 Jul 2015