The element iron is essential to human life. As part of hemoglobin, the oxygen-carrying protein found in red blood cells, iron plays an integral role in nourishing every cell in the body with oxygen. It also functions as a part of myoglobin, which helps muscle cells store oxygen. Without iron, your body could not make ATP (adenosine triphosphate, the body's primary energy source), produce DNA, or carry out many other critical processes.

Iron deficiency can lead to anemia, learning disabilities, impaired immune function, fatigue, and depression. However, you shouldn't take iron supplements unless lab tests show that you are genuinely deficient.

The official US recommendations for daily intake of iron are as follows:

  • Infants
    • 0-6 months: 0.27 mg
    • 7-12 months: 11 mg
  • Children
    • 1-3 years: 7 mg
    • 4-8 years: 10 mg
  • Males
    • 9-13 years: 8 mg
    • 14-18 years: 11 mg
    • 19 years and older: 8 mg
  • Females
    • 9-13 years: 8 mg
    • 14-18 years: 15 mg
    • 19-50 years: 18 mg
    • 50 years and older: 8 mg
  • Pregnant Women:27 mg
  • Nursing Women: 9 mg (10 mg if 18 years old or younger)

Iron deficiency is the most common nutrient deficiency in the world; worldwide, at least 700 million individuals have iron-deficiency anemia.1While iron deficiency is widespread in the developing world, it is also prevalent in developed countries. Groups at high risk are children, teenage girls, menstruating women (especially those with excessively heavy menstruation, known as menorrhagia), pregnant women, and the elderly.2,3

There are two major forms of iron: heme iron and nonheme iron. Heme iron is bound to the proteins hemoglobin or myoglobin, whereas nonheme iron is an inorganic compound. (In chemistry, "organic" has a very precise meaning that has nothing to do with farming. An organic compound contains carbon atoms. Thus "inorganic iron" is an iron compound containing no carbon.) Heme iron, obtained from red meats and fish, is easily absorbed by the body. Nonheme iron, usually derived from plants, is less easily absorbed.

Rich sources of heme iron include oysters, meat, poultry, and fish. The main sources of nonheme iron are dried fruits, molasses, whole grains, legumes, leafy green vegetables, nuts, seeds, and kelp. Contrary to popular belief, there is no meaningful evidence that cooking in an iron skillet or pot provides a meaningful amount of iron supplementation.65

Iron absorption may be affected by the following substances: antibiotics in the quinolone(Floxin, Cipro)4-8 or tetracycline9-11 families, levodopa,12methyldopa,13,14carbidopa,15penicillamine,16thyroid hormone,17captopril (and possibly other ACE inhibitors),18calcium,19-22soy,23zinc,24copper,25 or manganese,26 or multivitamin/multimineraltablets.58-59 Conversely, iron may inhibit their absorption, too.

In addition, drugs in the H2blocker or proton pump inhibitorfamilies may impair iron absorption.27