Iron

background

Iron is an essential mineral and an important component of proteins involved in oxygen transport and metabolism. Iron is also essential in the synthesis of neurotransmitters such as dopamine, norepinephrine, and serotonin. Approximately 15 percent of the body's iron is stored for future needs and mobilized when dietary intake is inadequate. The body usually maintains normal iron status by controlling the amount of iron absorbed from food.
The World Health Organization considers iron deficiency to be the largest international nutritional disorder. Approximately 50% of anemia worldwide is attributable to iron deficiency.
Iron deficiency may be determined by measurement of iron levels within the body, mainly serum ferritin levels, which may also help distinguish between iron deficiency anemia and anemia associated with chronic disease, such as chronic kidney disease (CKD).
There are two forms of dietary iron: heme and nonheme. Sources of heme iron include meat, fish, and poultry. Sources of nonheme iron, which is not absorbed as well as heme iron, include beans, lentils, flours, cereals, and grain products. Other sources of iron include dried fruit, peas, asparagus, leafy greens, strawberries, and nuts.
Vegan and vegetarian diets may increase the risk of deficiencies for certain vitamins and minerals, including iron.

Related Terms

Atomic number 26, carbonyl iron, dextran-iron, elemental iron, FE, Fer, ferric ammonium chloride, ferric chloride, ferric citrate, ferric phosphate, ferric pyrophosphate, ferric sodium pyrophosphate, ferric sulfate, ferrous ascorbate, ferrous carbonate, ferrous carbonate anhydrous, ferrous citrate, ferrous fumarate, ferrous fumarate sprinkles, ferrous gluconate, ferrous lactate, ferrous pyrophosphate, ferrous sulfate, heme-iron, iron dextran, iron proteinsuccinylate, iron sorbitol, iron sucrose, iron sulfate, iron(III)-hydroxide polymaltose complex, iron-choline citrate complex, iron-polysaccharide, iron-polystyrene sulphonate, ITF 282, NaFeEDTA, nonheme iron, reduced iron, saccharated iron, sodium ferric gluconate, sodium ferric gluconate complex (SFGC), sodium iron ethylenediaminetetra-acetate.

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
 
Anemia of chronic disease (Grade: A)
Taking iron orally with epoetin alfa (erythropoietin, EPO, Epogen®, Procrit®) is effective for treating anemia associated with chronic renal failure and chemotherapy.
Iron deficiency anemia (Grade: A)
Ferrous sulfate (Feratab®, Fer-Iron®, Slow-FE®) is the standard treatment for treating iron deficiency anemia. Dextran-iron (INFeD®) is given intravenously by healthcare providers to restore adequate iron levels in bone marrow when oral iron therapy has failed.
ACE inhibitor-associated cough (Grade: B)
Taking iron orally seems to inhibit cough associated with angiotensin-converting enzyme (ACE) inhibitors, such as captopril (Capoten®), enalapril (Vasotec®), and lisinopril (Prinivil®, Zestril®).
Preventing iron deficiency in menstruating women (Grade: B)
Iron supplementation has been shown to improve iron status in menstruating women.
Prevention of iron deficiency anemia in pregnancy (Grade: B)
Iron supplements have been shown to help prevent iron deficiency anemia in pregnant women. Anemia in pregnant women is associated with adverse outcomes such as low birth weight, premature birth, and maternal mortality. Screening by a qualified healthcare provider is needed. Low doses are generally well tolerated and associated with better compliance.
Attention deficit hyperactivity disorder (ADHD) (Grade: C)
According to preliminary data, taking iron orally might improve symptoms of attention-deficit hyperactivity disorder (ADHD). More research is necessary before a conclusion can be drawn.
Breathing problems (breath-holding attacks) (Grade: C)
Limited evidence suggests that iron supplementation may reduce the frequency and severity of breath-holding attacks in children. Additional studies are needed to confirm these results.
Fatigue in women with low ferritin levels (Grade: C)
Ferrous sulfate may improve fatigue primarily in women with borderline or low serum ferritin concentrations. Further research is needed to confirm these results.
Growth (Grade: C)
Mixed evidence exists with regard to the effects of iron supplementation on the growth of children. Further research is needed before conclusions can be drawn.
Improving cognitive performance related to iron deficiency (Grade: C)
Taking iron by mouth seems to improve cognitive function related to iron deficiency in iron-deficient children and adolescents. Further research is needed to confirm the potential benefit of iron in this indication. Iron supplements are not recommended for improving cognitive performance in non-iron-deficient people.
Infections (Grade: C)
Currently, there is a lack of evidence supporting the use of iron to prevent infections in children. Further research is warranted in this area.
Lead toxicity (Grade: C)
Iron deficiency may increase the risk of lead poisoning in children. However, the use of iron supplementation in lead poisoning should be reserved for those individuals who are truly iron deficient or for those individuals with continuing lead exposure, such as continued residence in lead-exposed housing.
Mental performance (infant and childhood development) (Grade: C)
Scientific evidence on the effects of iron on childhood development is conflicting. Some data suggest that iron supplementation primarily promotes psychomotor development, while others suggest more of an influence on intelligence. Further research is needed in this area.
Performance enhancement (in children) (Grade: C)
Limited evidence suggests that iron supplementation may improve physical performance in children. Further research is needed to confirm these results.
Pregnancy support (Grade: C)
Iron supplementation as nutritional support during pregnancy has been studied. Limited evidence suggests that prenatal use of iron, either with folic acid or as part of a multimicronutrient combination, may be beneficial. Further research is needed to determine the specific role of iron for pregnancy support.
Preventing iron deficiency in exercising women (Grade: C)
Preliminary studies suggest that iron supplementation can reverse mild anemia after exercise, improve energy, and enhance performance. However, other studies disagree. Further research is needed in this area before a conclusion can be made.
Prevention of iron deficiency after blood donation (Grade: C)
The results of early research indicate that elemental iron can adequately compensate for iron loss in females and males who donate whole blood up to four or six times per year, respectively.
Prevention of iron deficiency anemia due to gastrointestinal bleeding (Grade: C)
Intravenous high-dose iron sucrose therapy in patients with iron deficiency anemia due to gastrointestinal blood loss appears to be safe and therefore is a therapeutic option that may save time and improve patient compliance. More research is needed in this area.
Therapy for anemia after orthopedic surgery (Grade: C)
Early research reports that iron supplementation following elective hip or knee replacement surgery does not result in higher hemoglobin after surgery or a faster rate of increase in hemoglobin than placebo. However, recent evidence suggests that treatment of preoperative anemia with iron, with or without erythropoietin, reduced the need for blood transfusion and may contribute to improved patient outcomes. Further research is needed.
Treatment of predialysis anemia (Grade: C)
Adequate iron supplementation may be beneficial as an adjunct therapy with erythropoietin in the treatment of predialysis anemia. Predialysis anemia should be treated by a qualified healthcare provider. More research is needed in this area.