Absorbable Iron Supplements

Iron is an essential mineral responsible for transporting oxygen throughout the body. Iron deficiency, also known as anemia, often results in fatigue and decrease in physical performance. Pregnant women, vegetarians and teenage girls are among the highest-risk groups for anemia, and their physicians may recommend an iron supplement. In healthy adults, approximately 10 to 15 percent of dietary iron is absorbed, but many factors can influence the absorptivity of iron, including the types of iron supplements you choose.

Ferrous Fumarate

Ferrous fumarate is the iron salt of fumaric acid. The elemental iron content of a 325 mg tablet is 108 mg, as reported by the National Anemia Action Council. Boost its absorption with some vitamin C; have a glass of orange juice with your iron supplement. (See Reference 3)

Ferrous Gluconate

Ferrous gluconate is a ferrous form of iron salt that is better absorbed compared to ferric iron. The National Anemia Action Council reports that a 325 mg tablet contain 35 mg of elemental iron. Avoid having tea or coffee 2 hours before or after taking your iron supplements, as it may inhibit its absorption. (See Reference 3)

Ferrous Sulfate

Ferrous sulfate is a ferrous iron salt. The elemental iron content of a 325 mg tablet is 65 mg, according to the National Anemia Action Council. Do not take your iron supplement at the same time you consume calcium-rich foods or take a calcium supplement; calcium reduces iron absorption. (See Reference 3)

Iron Polysaccharide

Polysaccharide-iron complex is a newer option that differs from the iron salts--ferrous fumarate, ferrous gluconate and ferrous sulfate--and can stay in solution over variable pH levels. Although a tablet contains 150 mg of elemental iron, it is usually better tolerated than the most commonly prescribed ferrous iron supplements. No data is available to date regarding its absorption rate, but it is thought to be similar to ferrous iron salts. Taking your iron supplement on an empty stomach enhances its absorption.

Tablet Iron Supplements

Iron supplements are available in different forms: regular tablets, capsules, liquid and drop. Regular tablets and capsules are better absorbed and are also less expensive compared to liquid and drops, which may stain your teeth. Do not choose delayed-release or coated iron supplements; they may induce fewer side effects but are not absorbed as well. (See Reference 4)