Frequently used forms of iron in supplements include ferrous and
ferric iron salts, such as ferrous sulfate, ferrous gluconate, ferric citrate, and ferric sulfate [3,18].
Other forms of supplemental
iron, such as heme
iron polypeptides, carbonyl
iron,
iron amino - acid chelates, and polysaccharide -
iron complexes, might have fewer gastrointestinal side effects than ferrous or
ferric salts [18].