Your body is dependent on a mineral called iron for the transportation of oxygen and carbon dioxide through the body. If you have an iron deficiency due to a poor diet or a medical condition, you are likely to feel lethargic and weak. An iron supplement may be necessary to treat chronic deficiency, but you should work with your physician to choose an appropriate form of iron for your unique circumstances.
Dietary Sources of Iron
Although supplementation may be necessary in some cases, a healthy diet is the best source of iron. Foods rich in iron include fortified cereal, dark leafy greens, beans, lentils, oysters, beef and chicken liver and red meat. Dietary iron is classified as either heme -- coming from animal sources -- or nonheme iron. Heme iron is better absorbed, according to the Office of Dietary Supplements, but you should include both varieties in your diet.
Ferrous vs. Ferric
Over-the-counter iron supplements come in two preparations: ferrous iron salts and ferric iron. Ferrous salts are the better option as an oral supplement for two reasons. The salts are more readily available and they are better digested and absorbed, according to the Office of Dietary Supplements.
Since absorption through the digestive tract is a problem with ferric iron, typically, ferric supplements are given as an intramuscular or intravenous injection. Ferric carboxymaltose, sodium ferric gluconate and iron dextran are three types of ferric iron injections.
If you look through the supplements at the pharmacy, you are likely to see three different types of ferrous iron: ferrous sulfate, ferrous fumarate and ferrous gluconate. They differ in the amount of elemental iron -- or the amount of iron in the supplement that can be readily absorbed. Ferrous sulfate is the least expensive and most common of the three and contains 65 milligrams of elemental iron per 325 milligrams. Ferrous fumarate has the highest concentration of elemental iron at 108 milligrams per 325 milligrams of supplement, and ferrous gluconate has the least at 35 milligrams in a 325-milligram tablet.
Several groups of people are at risk for a deficiency because of an inability to absorb dietary iron properly, a need for additional iron or the loss of iron. These groups include pregnant women, teenage girls, toddlers, infants with a low-birth weight, individuals with renal failure and people with gastrointestinal conditions such as Crohn's disease. Since your body does not excrete much iron, iron toxicity is a serious risk associated with supplements. Do not take an iron supplement before consulting your physician.