Medicinal Inorganic Chemistry: Correcting Essential Metal-Ion Deficiencies

Essential metal ions are those for which there is a known requirement for good health in the body. When dietary intake does not, or cannot, maintain adequate tissue stores of an essential trace or ultratrace metal ion, metal-ion supplementation may be necessary. Simple salts of metal ions are often poorly tolerated, not well absorbed, or too rapidly excreted (or all three of these); therefore, appropriate ligand binding of the particular metal ion can significantly improve the success of supplementation efforts. The most common deficiency disorder, iron-deficiency anemia, is now treated with a number of iron complexes, e.g., Ferrochel™ and ferrous gluconate, that are superior to simple iron salts such as ferrous sulfate; others, such as ferric maltol, are being proposed as useful substitutes. Marginal deficiencies of trace and ultratrace elements, such as zinc, copper, manganese, and chromium, are purported to have long-term negative health effects, especially in aging or ill populations. Defining marginal deficiency is difficult, owing to lack of reliable and accurate biomarkers for the determination of trace element status. Keywords: essential trace metal; deficiency disease; iron-deficiency anemia; bioavailability; hydroxypyrone; selenomethionine; zinc; copper; dietary reference intake; manganese; reactive oxygen species