Functions

There is 3-5 grams of iron in the body at any time, two thirds of this is as heme in hemoglobin of the blood, the other third is bound in ferritin stores. The iron in red blood cells carries oxygen to tissues. Without iron, heme cannot be made and new red blood cells cannot be produced efficiently. Iron is also essential in the production of genetic material, thyroid hormones, connective tissue and energy production.

Uses

Iron deficiency anemia.

Deficiency

Iron is the most commonly deficient nutrient in the US. Symptoms of iron deficiency include weakness and fatigue, headaches, apathy, rapid heartbeat, severe menstrual pain and bleeding, cracks in the corner of your mouth, eye inflammation, mouth ulcers, hair loss. About 10-15% of dietary iron is absorbed, although the amount appears to increase in deficiency. Ferric iron (with a 2+ charge) is absorbed from plant sources, and ferrous iron (with a 3+ charge) is absorbed from animal sources.

Antagonists

Calcium supplements, zinc supplements, oxalates in green leafy vegetables and tannins in tea and coffee can reduce absorption. Milk, albumin and soy proteins may also reduce absorption. Iron is antagonistic to the antioxidant action of vitamin E. Iron competes with magnesium, copper, calcium and zinc for absorption in the intestine, and excess intake of one of these minerals could produce a deficiency in the others.

Co-factors

Taking Vitamin C in the same meal as nonheme iron improves absorption by up to 50%; vitamin A and beta-carotene may also improve absorption. Otherwise 20-30% of it is absorbed of the amount consumed. Adequate stomach acid is required for absorption because it must be in the ferrous form.

Drug Interactions

None known.

Dose

RDA Men 10 mg; Women premenopause 15mg, 10mg postmenopausally, pregnancy 30mg.

In anemia, dose may be larger.

Toxicity

Iron toxicity may occur with repeated transfusions, with polycystic disease of the kidneys, with iron poisoning.

Symptoms of toxicity include nausea and vomiting, shock, convulsions and coma.

Excess iron may be associated with atherosclerosis. Do not take iron if it is not indicated by a blood study that you are deficient.

Sources

Iron sources include: liver, lean meat, dried beans.