General Description
Iron is a metallic mineral present in minute amounts in all cells
of the human body. The majority of bodily iron is found in hemoglobin,
the compound in red blood cells that carries oxygen from the lungs
to tissues throughout the body. Iron is also a crucial component
of myoglobin, a compound that facilitates oxygen use and storage
in muscle tissues. Many enzyme reactions require iron, and it plays
an important part in numerous biological processes. Too little iron
can interfere with these vital functions and lead to disease and
death. Iron deficiency is the most common known form of nutritional
deficiency. Supplemental iron is available in a number of forms
including iron sulfate, fumarate, succinate, glycinate, and gluconate.
Food sources
The richest dietary sources of iron include meat (especially liver),
poultry, and fish. Brewer's yeast, kelp, blackstrap molasses,
nuts, and whole grains are also good sources.
Health applications
- Anemia
- Prenatal nutrition
- Growth and development
- Celiac disease
Deficiency symptoms
Iron deficiency can cause anemia, a condition in which abnormally
low hemoglobin levels or red blood cell concentrations impair
oxygen delivery, causing weakness, paleness, and irregular heartbeat.
Although there are many different types of anemia with a variety
of causes, iron-deficiency anemia (IDA) remains the most common
type. IDA is most prevalent in young children and in women of
child-bearing age (particularly pregnant women). Several factors
can contribute to development of IDA: insufficient dietary iron
intake, excessive blood loss (as seen in heavy menstrual bleeding),
and gastrointestinal disorders that impair iron absorption (such
as celiac disease1 and H. pylori infection
2,3). The Centers for Disease Control and Prevention
(CDC) recommends periodic screening for anemia among high risk
populations of infants and preschool children, among pregnant
women, and among nonpregnant women of child-bearing age.4
Prenatal nutrition
Because iron deficiency is common among pregnant women, the CDC
recommends universal iron supplementation to meet the iron requirements
of pregnancy.4 Research indicates that pregnant
women not taking iron supplements are 11 times more likely to
develop anemia than pregnant women taking supplements.5
Studies indicate that IDA during pregnancy increases the risk
for preterm delivery and low birth weight.6,7
It is also believed that IDA during pregnancy may contribute to
low iron status in newborns.8
Growth and development
Iron-deficiency anemia in infants and preschool children is a
serious health concern because iron plays a vital role in normal
growth and development. Studies indicate that IDA in infants impairs
central nervous system development, language capabilities, and
balance-coordination skills.9,10 Other research
indicates that IDA during childhood increases the likelihood of
mild to moderate mental retardation,11 and
that iron supplementation can improve learning processes in anemic
children.12
Dosage/toxicity
The recommended dietary allowance for iron is 10 mg/day for children
12 and under, 15 mg/day for women ages 12-50, 10 mg/day for women
over 50, 12 mg/day for males aged 12-19, and 10 mg/day for men
over 20. The CDC recommends that women supplement 30 mg of iron
per day during pregnancy to meet increased prenatal demand. Patients
diagnosed with IDA are often treated with 60 to 120 mg of oral
iron supplements per day until blood iron levels normalize. Iron
supplementation above the RDA is not recommended for nonpregnant,
nonanemic people because of the potential for iron overload, which
can cause liver damage and cardiovascular complications. Iron
overload is usually caused by excessive iron intake or disorders
associated with increased intestinal iron absorption such as alcoholism,
liver disease, diabetes, or a hereditary metabolic disorder known
as idiopathic hemochromatosis.13-17 |
