Also indexed as:Ferrous Sulfate
Iron: Main Image

How to Use It

If a doctor diagnoses iron deficiency, iron supplementation is essential. To treat iron deficiency, a common recommended amount for an adult is 100 mg per day; that amount is usually reduced after the deficiency is corrected. When iron deficiency is diagnosed, the doctor must also determine the cause. Usually it’s not serious (such as normal menstrual blood loss or blood donation). Occasionally, however, iron deficiency signals ulcers or even colon cancer.

Some premenopausal women become marginally iron deficient unless they supplement with iron. However, the 18 mg of iron present in many multivitamin-mineral supplements is often adequate to prevent deficiency. A doctor should be consulted to determine the amount of iron that is needed.

Where to Find It

The most absorbable form of iron, called “heme” iron, is found in oysters, meat and poultry, and fish. Non-heme iron is also found in these foods, as well as in dried fruit, molasses, leafy green vegetables, wine, and iron supplements. Acidic foods (such as tomato sauce) cooked in an iron pan can also be a source of dietary iron.

Possible Deficiencies

Vegetarians eat less iron than non-vegetarians, and the iron they eat is somewhat less absorbable. As a result, vegetarians are more likely to have reduced iron stores.1 However, iron deficiency is not usually caused by a lack of iron in the diet alone. An underlying cause, such as iron loss in menstrual blood, often exists.

Pregnant women, marathon runners, people who take aspirin, and those who have parasitic infections, hemorrhoids, ulcers, ulcerative colitis, Crohn’s disease, gastrointestinal cancers, or other conditions that cause blood loss or malabsorption are likely to become deficient.

Infants living in inner city areas may be at increased risk of iron-deficiency anemia2 and suffer more often from developmental delays as a result.3, 4 Supplementation of infant formula with iron up to 18 months of age in inner city infants has been shown to prevent iron-deficiency anemia and to reduce the decline in mental development seen in such infants in some,5 but not all,6 studies.

Breath-holding spells are a common problem affecting about 27% of healthy children.7 These spells have been associated with iron-deficiency anemia,8 and several studies have reported improvement of breath-holding spells with iron supplementation.9, 10, 11, 12

People who fit into one of these groups, even pregnant women, shouldn’t automatically take iron supplements. Fatigue, the first symptom of iron deficiency, can be caused by many other things. A doctor should assess the need for iron supplements, since taking iron when it isn’t needed does no good and may do some harm.

Best Form to Take

All iron supplements are not the same. Ferrous iron (e.g. ferrous sulfate) is much better absorbed than ferric iron (e.g. ferric citrate).13, 14 The most common form of iron supplement is ferrous sulfate, but it is known to produce intestinal side effects (such as constipation, nausea, and bloating) in many users.15 Some forms of ferrous sulfate are enteric-coated to delay tablet dissolving and prevent some side effects,16 but enteric-coated iron may not absorb as well as iron from standard supplements.17, 18, 19 Other forms of iron supplements, such as ferrous fumarate,20, 21 ferrous gluconate,22 heme iron concentrate,23, 24, 25, 26 and iron glycine amino acid chelate27, 28 are readily absorbed and less likely to cause intestinal side effects.

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2024.