Iron
Recommended Intake
Iron Deficiency
Iron Toxicity
Major Food Sources
Anemia
Hemochromatosis
Heart Disease and Cancer
Tips for Increasing Your Iron Intake

Iron is a mineral that is found in every living cell. Iron exists in two forms — heme and nonheme. Heme iron is part of the hemoglobin and myoglobin molecules in animal tissues. About 40 percent of the iron in meat is in the heme form. Nonheme iron comes from animal tissues other than hemoglobin and myoglobin, and from plant tissues. It is found in meats, eggs, milk, vegetables, grains, and other plant foods. The body absorbs heme iron much more efficiently than nonheme iron.

Iron's functions include:

• carrying oxygen to cells throughout the body
• holding oxygen within the cells, especially heart and skeletal muscle cells
• forming collagen, which is the major protein that makes up connective tissue, cartilage, and bone
• helping fight infection by synthesizing certain enzymes needed for immune function
• helping convert beta carotene to vitamin A
• helping make amino acids, which are the building blocks of protein
• aiding drug detoxification pathways in the liver
• forming part of an enzyme that is essential for the production of several neurotransmitters
• synthesizing cellular components that are important to metabolism

Recommended Intake
Iron needs are greatest during times of rapid growth-childhood, adolescence, and pregnancy. Also, women have higher requirements than men, to replace the iron that is lost with monthly menstruation.

Iron Deficiency
Groups of people who are susceptible to being iron deficient are:

• women of childbearing years
• female runners
• older infants
• children
• the elderly
• low-income groups
• minorities

Symptoms of iron deficiency include:

• chronic tiredness
• reduced ability to concentrate
• increased susceptibility to colds and infections
• high blood sugar
• impaired growth

Iron deficiency at critical stages in brain development during infancy and childhood can cause the following:

• impairment of short-term memory
• poor exercise ability
• poor scholastic test scores
• hyperactivity
• decreased attention span
• reduced IQ

Once this deficiency is corrected, some of these difficulties will be resolved, but others may be permanent. If not corrected, iron deficiency can progress to anemia.

Iron Toxicity
At high levels, iron is toxic. And since the body has no effective means of excreting excess iron, it is possible, although not very common, for iron to accumulate. Iron pills and supplements containing iron that are designed for adults can cause poisoning in children.

Other effects of too much iron include:

• damage to the liver and other tissues
• reduced ability to use other trace minerals (zinc, iodine, and selenium)

Major Food Sources
Food sources of mostly heme iron (contain some nonheme as well)

Food sources of nonheme iron:

Anemia
Not consuming and/or absorbing enough iron can lead to iron-deficiency anemia. The symptoms of anemia include:

• fatigue
• weakness
• pale skin
• headache
• fingernail changes
• heart palpitations
• inability to stay warm
• shortness of breath during or after physical activity
• hair loss

Iron-deficiency anemia is usually treated by increasing iron intake through dietary sources and iron supplementation.

Hemochromatosis
People with the genetic disease hemochromatosis absorb excessive amounts of iron. This leads to a buildup of iron in the bloodstream and in certain organs, including the liver, muscles, pancreas, and heart. Without treatment, high levels of iron can damage these organs. Treatment involves eating a diet low in iron and donating blood regularly.

Heart Disease and Cancer
Some research has suggested that excess levels of iron in the body may lead to an increased risk for heart disease or cancer. These effects may be due to how the body metabolizes iron, as opposed to how much iron is in the diet. However, the research in these areas is still inconclusive.

Tips for Increasing Your Iron Intake
The amount of iron your body absorbs varies depending on several factors. For example, your body will absorb more iron from foods when your iron stores are low, and will absorb less when stores are sufficient.

In addition, certain dietary factors affect absorption:

• Heme iron is absorbed more efficiently than nonheme iron.
• Heme iron enhances the absorption of nonheme iron.
• Vitamin C enhances the absorption of nonheme iron.
• Some substances decrease the absorption of nonheme iron (but, consuming heme iron and/or vitamin C with nonheme can help compensate for these decreases):

  oxalic acid, found in spinach and chocolate (oxalic acid is broken down with cooking)
  phytic acid, found in wheat bran and beans (legumes)
  tannins, found in tea
  polyphenols, found in coffee

To increase your intake and absorption of dietary iron, try the following:

• Combine heme and nonheme sources of iron.
• Eat foods rich in vitamin C with nonheme iron sources. Good sources of vitamin C include:

  bell peppers
  papayas
  oranges and orange juice
  broccoli
  strawberries
  grapefruit
  cantaloupe
  tomatoes and tomato juice
  potatoes
  cabbage
  spinach and collard greens

• If you drink coffee or tea, do so between meals rather than with a meal.
• Cook acidic foods in cast iron pots. This can increase iron content up to 30 times.