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Iron in diet

Alternative names

Iron is an important trace mineral that is found in every cell of the body, usually combined with protein .


Iron is an essential mineral for humans because it is part of blood cells. About 30% of the iron in the human body is in storage to be readily available to replace any that is lost.

Iron is essential to the formation of hemoglobin and myoglobin, which carry oxygen in the blood and muscles. It also makes up part of many proteins and enzymes in the body.

Iron deficiency is the most common nutritional deficiency worldwide. Although full-blown anemia is rarely evident, partial deficiency is widespread.

Symptoms of decreased iron stores include general fatigue , shortness of breath , headache , irritability, and/or lethargy . Other symptoms include pica (the development of an appetite for unusual substances such as paper or clay products) and pacophagia (the development of an appetite for ice).

If you have constant unusual signs of tiredness , see your health care provider. There are many causes of such symptoms, and simply taking an iron supplement may not be enough.

Those at risk for low iron stores include:

  • Menstruating women (Women with heavy periods are particularly at risk.
  • Pregnant and postpartum women -- extra iron is needed to meet the needs of the growing fetus and to make up for iron lost due to blood loss during childbirth
  • Infants are born with iron stores that last about six months. An infant's additional iron needs are met by breast milk. A non-breast-fed infant's iron needs can be met with an iron supplement or iron-fortified infant formula. As babies move to solid foods, foods containing high amounts of iron should be selected to prevent the development of iron deficiency.
  • Toddlers between 1 and 4 years of age are at risk for developing iron deficiency because of rapid growth and a lack of sufficient iron in their diets unless iron-fortified foods or a supplement is available. Because milk is a very poor source of iron, children who drink large quantities of milk at the expense of other foods may develop "milk anemia." Recommended milk intake is two to three cups per day for toddlers.
  • Adolescents -- both boys and girls -- traditionally have been prone to anemia because of rapid growth rates, erratic eating habits, and concerns about body image.
  • Long-distance runners -- demanding exertions may damage red blood cells
  • Strict vegetarians (animal products contain the most bioavailable form of iron)
  • People with bleeding lesions in their gastrointestinal tract.
  • People with absorption problems in the gastrointestinal tract, such as celiac sprue or having had portions of the intestines removed, which may lead to low levels of iron.

Food Sources

The best food sources of easily absorbed iron are animal products, which contain heme iron. Iron from vegetables, fruits, grains, and supplements (non-heme iron) is harder for the body to absorb. If you mix some lean meat, fish, or poultry with beans or dark leafy greens at a meal, you can improve absorption of vegetable sources of iron up to three times. Foods rich in vitamin C also increase iron absorption.

Some foods decrease iron absorption. Commercial black or pekoe teas contain substances that bind to iron so it cannot be used by the body.

Consider the amount of absorbable iron in a food, not just the total iron content. Iron sources that have high iron availability include the following:

  • Oysters
  • Liver
  • Lean red meat (especially beef)
  • Poultry, dark red meat
  • Tuna
  • Salmon
  • Iron-fortified cereals
  • Dried beans
  • Whole grains
  • Eggs (especially egg yolks)
  • Dried fruits
  • Dark leafy green vegetables

Reasonable amounts of iron are also found in lamb, pork, and shellfish. Non-heme iron is found in the following:

  • Whole grains
    • wheat
    • millet
    • oats
    • brown rice
  • Legumes
    • lima beans
    • soybeans
    • dried beans and peas
    • kidney beans
  • Seeds
    • almonds
    • Brazil nuts
  • Dried fruits
    • prunes
    • raisins
    • apricots
  • Vegetables
    • broccoli
    • spinach
    • kale
    • collards
    • asparagus
    • dandelion greens

Side Effects

Iron deficiency most commonly manifests itself as iron deficiency anemia . Iron deficiency and iron deficiency anemia can occur during periods of rapid growth, during pregnancy, and among women who are menstruating more than usual. It can also be associated with any type of intestinal loss of blood, frequent donation of blood, and from the inability to absorb iron efficiently.

Initial symptoms of iron deficiency anemia include the following:

  • Fatigue
  • Lack of energy
  • Dizziness

Weight loss and lowered immunity may also indicate iron deficiency. The symptoms can be alleviated once the cause of the iron deficiency has been determined.

It is unlikely that iron toxicity can develop from an increased dietary intake of iron alone. Children have been known to develop iron toxicity by increased intake of iron supplements, however. Symptoms of iron toxicity include the following:

  • Fatigue
  • Anorexia
  • Dizziness
  • Nausea
  • Vomiting
  • Headache
  • Weight loss
  • Shortness of breath

A grayish color to the skin is a possible indication of iron toxicity.

Hemochromatosis is a genetic disorder that affects the regulation of iron absorption. The incidence may be as high as 5 in 1,000 in Caucasians. Treatment consists of a low-iron diet, no iron supplements, and phlebotomy (blood removal) on a regular basis.

Excess storage of iron in the body is known as hemosiderosis. The increased iron stores come from the consumption of excessive iron supplements or from receiving frequent blood transfusions, not from increased iron intake in the diet.


According to

According to USDA rec , the allowances of dietary iron intake are as follows:

  • Males and females
    • Younger than 6 months: 6 mg
    • 6 months to 1 year: 10 mg
    • 1 to10 years: 10 mg
  • Males
    • 11 to 18 years: 12 mg
    • 19 and older: 10 mg
  • Females
    • 11 to 50: 15 mg
    • 51 and older: 10 mg
    • Pregnant: 30 mg
    • Lactating: 15 mg

Any male or postmenopausal female with iron deficiency should be evaluated by a health care provider to rule out whether the problem may be due to a more serious gastrointestinal cause such as ulcers, polyps, or tumors.

Update Date: 1/19/2003

Steven Angelo, M.D., Assistant Professor of Medicine, Yale School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network.

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Last updated: Tue, 06 Jan 2009 00:20:03 GMT