Chelated Minerals

By Chuck Michaelis BS, B.Ch.

The word chelate comes from the Greek word “chele” which translates to English as “claw”.  The reasons for this designation becomes clear when we examine the structures of chelates. 

Chelates are the result of the sharing of electrons between a metal and a ligand (from the Latin word ligare, “to bind”).  A ligand is usually either an anion (a negatively charged ion) or a molecule which has an atom with an available pair of valence electrons.  Common ligands contain nitrogen, oxygen, sulfur, halogens or a combination of them due to their electronic structures.  Atoms that can share their electrons are called donor atoms.  Ligands with a single donor atom are known as monodentate (Latin, “single toothed”) ligands.  Polydentate ligands have two or more donor atoms.  Only polydentate ligands can form chelates.  These ligands grasp a metal between their electronic “teeth” or, to mix a metaphor, appear to “claw” the metal.

Divalent and trivalent metals are especially well suited to forming the coordination bonds which are characteristic of chelates.  A coordination bond, also known as a complex, consists of the metal and the ligand(s), which align so that the available electrons on the donor atoms are in proximity to the metal. 

Metal chelation is extremely important in biological systems.  Most enzymes require a chelated metal in their structure to be effective.  Vitamins like vitamin B12 (cyanocobalamin) contain a metal (cobalt) complexed to the tetradentate porphyrine ring and a nitrogen in a pseudonucleotide.  Porphyrine also plays a vital role in chelating iron to form hemoglobin.  Clinically important chelating agents include EDTA (ethylene diamine tetraacetic acid), a hexadentate ligand. EDTA is used to remove lead and other heavy metals from the body and is used to help remove calcium from plaquing on arterial walls in IV drip chelation therapy.  EDTA does not appear to work very well in this capacity when administered orally.

We offer several mineral supplements, most of which are amino acid chelates.  Amino acids are excellent polydentate ligands and have the advantage of being readily recognized and taken up by cellular transport systems, making excellent absorption vehicles.  Absorption rates are considerably higher than inorganic salts and rank at the top of organic sources. Our Calcium Aspartate, Magnesium Aspartate and Cal-Mag Aspartate products use L-aspartic acid (tridentate ligand) as a carrier.  Aspartate has several advantages.  It has a relatively low molecular weight so that a mineral complexed with it will show a reasonable yield (about 23% for calcium and 14% for magnesium).  It is a participant in transamination reactions to convert to Kreb’s cycle intermediates and is important in purine and pyrimidine synthesis. Aspartic Acid is glucogenic and is important in ammonia detoxification biochemistry.  Another important amino acid in mineral chelation is L-glycine.  Unfortunately, L-glycine is only a bidentate ligand so it cannot be used for trivalent metals.  Several other ligands are commonly used in chelation for supplementation.