Firstly, we will look at the two most basic and cheapest form of mineral that are widely available.


An oxide is probably the closest form to the raw metal. Oxides are formed constantly where any metal I exposed to oxygen, for example, iron oxide we know as “rust”. How soluble is rust? Not very soluble. All oxides are mostly insoluble forms of mineral, for instance magnesium oxide is insoluble; however it is used in commercial formulations as a source of magnesium. Typically oxides can only be dissolved in acids, hence they do have some availability within the stomach. The availability of oxides is extremely low and when used in fertilisers are usually better in formulations that target the soil rather than foliar sprays targeting plant absorption. Some oxides such as magnesium oxide are useful animal supplements but only if they have been firstly calcined correctly (opens up the particle) and then ground consistently to increase availability. Although cheap, most other oxides have very limited use in animal nutritional.


Like oxide, sulphate mineral forms are strictly inorganic, in that they are not tied to any organic substance, being either an amino acids, a carbohydrates, or an organic acid. Unlike the oxide mineral form where the bond is with oxygen, the bond on a sulphate mineral ion is with sulphur. Unlike the oxide form, the sulphate forms, depending on hydration, are normally readily soluble in water. However they are highly reactive, the mineral immediately upon being dissolved is highly unstable and is looking to attach itself to any negatively charged ions that may be around. Upon absorption research has shown that the body will identify sulphates at even quite low levels as a free radical elements and will tend to kick them out of the blood quickly to limit toxicity risk to the cells, these will tend to largely wind up in the organs, primarily the liver and kidneys. By doing this the body has limited immediate risk, however from there the mineral needs to be either released back into the bloodstream or excreted, this can be a poorly regulated process whereby much is lost through excretion and occasionally certain situations can also trigger toxic release. This is of particular risk with copper.


Secondly, let us look at the other main type of mineral available, variously referred to chelated or organic minerals. This class of minerals is available in a wide range of options.


The word “chelate” is related to the Greek word for “claw” it refers to a substance consisting of amino acid molecules that are tightly bound to a metal ion, this bond between the metal ion insures that wherever the amino acid goes the metal ion is carried with it. Chelation agents can take many forms within the soil, plant and animal, these can be, amino acids, organic acids, sugars, as well as a host of more novel chemical forms, including a number of artificially synthesized chelating agents developed in the laboratory. When it comes to amino acids chelates, depending on whether the chelate is being developed for use in the soil, plant, or animal, and how and where the mineral is to be delivered within the body, will depend on what amino acid is used in the chelation process. Some chelating agents such as those developed for use in certain chemical sprays are designed to bind a particular essential mineral, thus seriously interfering with a plants metabolism. Dosed at the correct rate this type of chemical will kill the plant through induced deficiency. Such chemical chelators as EDTA are not far removed from weed killers in that they were originally developed to bind calcium and magnesium, the majority of chelation based weed killers are designed to bind manganese. EDTA is now used in a wide range of areas where it is important to bind minerals in such products as, detergents, industrial chemicals, blood storage etc…. As you can see different chelation agents have a wide range of uses, not all of them nutritional, artificially developed chelation agents while maybe suitable for industrial purposes are not good for use on soils or in animal nutrition. More specific information on EDTA and its uses later in the article.


The chelates listed below are what could be considered authentic chelates. Although varying in levels of efficacy, these are all chelates that could conceivably occur in nature. They are all metal ions attached to naturally occurring amino acids or carbohydrates.

Formulation Category Solubility Availability

“Amino acid chelates” good absorption in both plants and animals, a correctly manufactured amino acid chelate should be translocated to every cell in the body and plant.
Glycine chelates (glycinate) a true amino acid chelate - soluble – excellent absorption, glycine makes up part of glutathione the key antioxidant in the cytoplasm of every cell. Mineral tied to glycine is translocated to every cell.
Proteinate - soluble – medium absorption – proteinates are made up of a number of amino acids attached to a single metal ion. As such this is a large molecule offering poorer absorption, when compared to either an amino acid chelate or a glycine chelate The less controlled manufacturing process means proteinates are less costly to manufacture.
Polysaccharide - soluble – medium availability - unstable – no rumen protection

The AAFCO (Association of American Feed Control Officials) was among the first organisations to exactly define what constituted a true Amino Acid Chelate. This has since become the standard definition used throughout the feed and fertiliser industries.

AAFCO basic definitions for chelates as follows:
METAL AMINO ACID CHELATE – The product resulting from the reaction of a metal ion from a soluble metal salt with amino acids. It has a mole ratio with 1 mole of metal to 1-3 (preferably 2) moles of amino acid to form coordinate covalent bonds. The average weight of the amino acids must be approximately 150 daltons and the resulting molecular weight of the chelate must not exceed 800 daltons. When used as a commercial feed ingredient it must be declared as a specific metal amino acid chelate. (Adopted 1988)

METAL PROTEINATE – The product resulting from the chelation of a soluble salt with amino acids and/or partially hydrolyzed protein. It must be declared as an ingredient as the specific metal proteinate: i.e., copper proteinate; zinc proteinate; magnesium proteinate; iron proteinate; cobalt proteinate; manganese proteinate; or calcium proteinate. (Amended 1987).

METAL POLYSACCHARIDE COMPLEX – The product resulting from the complexing of a soluble salt with a polysaccharide solution declared as an ingredient as the specific metal complex: i.e., copper polysaccharide complex; zinc polysaccharide complex; iron polysaccharide complex; cobalt polysaccharide complex; and manganese polysaccharide complex. (Adopted 1973).

Additional to this more recent research has shown that to achieve a truly functional chelate, the following further requirements should be met:

1) The chelate must be electrically neutral. The chelate must not be complexed with an easily ionisable anion, such as a halogen or a sulphate group. The ligand must satisfy both the oxidative state and a coordination number of the metal ion.

3) The chelate must have a high enough stability constant to avoid competitive chemical interactions prior to absorption, yet the stability constant must not be so high as to interfere with release or cause the binding of other elements during digestion and absorption.

4) The ligand (Amino Acid) must be small enough to be easily absorbed through the intestinal wall from whence it will be translocated to the widest range of body cells possible. (some amino acids are more specific to certain body cells than others).


There is not much point in spending money and dosing a trace mineral if it is not going to perform the function it was designed for. In order to work efficiently it needs to at least meet the basic three criteria above.


Formulation Category Solubility Availability
EDTA Synthetic chelate - Soluble – synthetic ligand – Too stable, very high stability constant, ties up other minerals
EDDHA Synthetic chelate - Soluble - synthetic ligand - Too stable, very high stability constant, ties up other minerals


Formulation Category Solubility Availability
Oxides Raw mineral – Solubility Low –stability good - availability Low
Sulphates Salt – Solubility good – Stability poor – Availability Moderate - subject to complexation with other minerals, can negatively affect rumen performance, particularly copper sulphate.
Nitrates Salt – Solubility good – stability poor - availability good - subject to complexation with other minerals


An authentic chelate has all the properties specified above by the AAFCO.
There are a number of companies worldwide that manufacture “authentic chelates” using Glycine. In order to create a true glycinate a single mineral ion is bonded with two molecules of glycine (the smallest and lightest amino acid) creating a fully chelated product. The plant recognises this molecule as a protein similar to nitrogen, the body recognizes the chelate as a complexed amino acid in similar form to that found in nature. In the body the glycinate passes through the stomach (or rumen) untouched and is absorbed directly through special micro channels in the small intestine, from there because the mineral is attached to glycine the body will translocate it to every cell of the body where glycine is utilized to form glutathione. In the plant this amino acid bond allows the mineral to travel in the phloem quite readily to the growing points of the leaf, as well as to any flowers, fruit and berries. In the same way as glycine is used in the body, it is also used in plant cells to create the cells primary antioxidant, glutathione, attaching a mineral to glycine effectively allows the mineral direct access to the cell. Whereas normally minerals translocate through the plant very poorly, because of the amino acid bond the minerals are rapidly translocated to where they are most needed.


Amino acids are natural chelators, under the right conditions, and when in contact with positively charged metal ions they readily form stable chemical bonds. It is important that the bond formed is strong and stable enough not to fall apart when subject to absorption or digestion, yet not so strong where the bond cannot be broken apart, or the chelation agent is so powerful that it complexes other essential elements. Amino acids are ideal chelators, they appear in the animal’s diet already in combination with minerals, and they are well utilized within every cell of the body, and are in fact readily absorbed directly to the cell. Some combinations of minerals and amino acids do not form good chelates because the bonding is too weak. For example, if you try to use the amino acid glutamic acid as the chelator and sodium as the mineral ion, you get monosodium glutamate, which is an “organic salt”, not a chelate. Generally speaking, sodium and potassium do not form viable chelates. Amino-acid chelation bypasses competitive interactions that can occur between different minerals when they are provided as inorganic salts. Use of chelated forms of mineral essentially bypasses the problem by taking a totally different route for absorption and storage.


Dr D. Wayne Ashmeade, leading scientist, researcher, and author, Ashmeade and his father before him have been at the leading edge of scientific study of chelates since the 1960’s. D Wayne Ashmeade states clearly, that in his opinion EDTA chelate mineral forms are “poisoning” and should not be used. It is interesting he should use the word “poisoning” to describe this particular chelation agent, any doctor knows EDTA since the 1950’s has been the first line of defence against heavy metal poisoning. Such issues as lead poisoning are routinely treated by giving doses of EDTA to the patient in order to trigger the binding and release of the toxin. However this ability to bind to a mineral, any mineral, is the very essence of the problem. When used in a mineral dietary supplement, EDTA doesn’t just bind the mineral it is associated with, it will bind every other positively charged mineral it comes into contact with during digestion and even after absorption. As a result induced mineral deficiency can ultimately lead to the death of the plant or animal through deficiency related disease, hence in this context these compounds can rightly be described as “poisoning”.

EDTA or ethylenediaminetetraacetic acid is an artificially synthesized molecule used for complexing a wide range of minerals. A synthetic chelating agent, EDTA has an interesting history, with what I believe is a potentially terrifying future unless its future use is limited. First patented in 1941, EDTA was initially developed for removing calcium impurities effecting dye colours used in textiles, later it was also used for cleaning mineral residue build-up in boiler pipes. These days it is used within many industrial processes, being widely used by industry in such things as cosmetics, medicine, industrial, and agricultural chemicals, just to name a few. One of its more novel uses is in stored blood where it is used to remove calcium in order to prevent the natural clotting effect. EDTA is an extremely powerful chemical chelation agent, it is one chemical that cannot be utilised effectively by either plant or animal because it simply never breaks down. The use of EDTA in industry has been recently reviewed and the quantities used in industrial processes have been tightened in much of the world, particularly Europe. These restrictions are due to very real environmental concerns to do with the build-up of this powerful chelation agent in water and soil. EDTA has also been used since the 1960’s as a cheap chelating agent in some of the cheaper mineral supplements targeting livestock. In Europe along with much of the western world, it is now illegal to use EDTA in any mineral supplement or food destined for animal or human consumption. The law in New Zealand however does not currently cover its use in animal supplement products, it is being sold by a number of companies and it is still common to see it being used on many New Zealand dairy farms. Where this chemical makes up part of a mineral blend it will further complicate many of the common deficiency diseases, particularly those connected to calcium and magnesium deficiency. EDTA as it is designed to do, effectively binds minerals such as calcium very tightly and makes the mineral unavailable to the organism, be it plant or beast. The complexed molecule is large, and it carries a very large negative charge on the molecule, this is measured in scientific terms as a stability constant number (the number is exponential), the stability constant numbers for EDTA show it to have a binding power that is up to 10 million times that of a natural amino acid based chelate such as a glycinate. In the body the bulk of the EDTA is rapidly excreted along with any minerals it picks up in the digestive system on the way. A small amount will however be absorbed directly to the bloodstream where it will very efficiently mop up available magnesium and calcium along with any other positively charged minerals it comes into contact with, from there it is excreted along with the minerals it has complexed. In the plant it normally enters the underside of the leaf where it can also complex other minerals. Although EDTA is still legal for spraying onto crops in Europe, research is now showing that residual effects of active EDTA left in the soil and finding its way into the waterways can lead to problem build ups and downstream mineral binding in the environment. Too much EDTA can be quite toxic to certain plants, if fact variations on the EDTA formula are used in the many of the popular modern weed killers, particularly those that target grass species. These chemicals are designed to kill by binding essential minerals, thus creating a chemically induced mineral deficiency within the target plant. If you choose to use any product containing EDTA you will over time induce deficiencies in your animals and the environment.


Research has shown that chelated minerals are very important to animal health and plant nutrition; hence there are a few companies that have introduced their own brands of so called “chelated mineral” combinations. Some of these products lack research, or quote selective in house research in order to create the impression of efficacy. Many companies make claims to do with the quality of minerals which when checked through laboratory testing are not always based on facts, particularly chelated forms. Such claims are made in the knowledge that they can be be hard to disprove, claims such as, “contains amino acid chelates”, “organic minerals”, or “derived from organic sources”. When we have tested these formulations it soon becomes apparent that they are often simply sulphate based minerals masquerading as chelates or mixtures of sulphate based minerals blended with protein powder to give the impression of chelation. It is only through using a time consuming and expensive analysis system called “Xray diffraction spectrometry” that we can test these products and identify that they are not what they claim to be. The terms “chelate”,“amino acid” and “organic”, are loosely defined, and to date because of limitations in testing have seldom been subject to any real scrutiny from within the industry. The best way to insure that you do not pay good money for one of these non-chelated mixtures is to check the label data thoroughly, identify clearly where each ingredient has been sourced, identify the manufacturer of any chelates in the blend. The client should also demand trial data from that manufacturer on the efficacy of the materials used. The label should list a reputable manufacturer that manufactures to a set specification and strict process protocols. Stay away from products that do not carry a label, these are both potentially dangerous and will seldom offer value. Be wary of Asian knock off products that claim to be chelates yet may be simple mixtures of mineral and protein powder.

Minerals in animal nutrition

Since the 1950’s plant and animal research began to identify the complex forms by which minerals are absorbed by the body. The late 1950’s saw the development of the first mineral chelate or truly organic mineral forms. Since then there has been much debate as to the best form of mineral to use. In the area of animal mineral research, the most reliable trial work on chelates has clearly established a strong correlation between mineral form and a wide range of performance advantages in cattle. These include such things as improvement in conception rates, less disease, and increased milk production. Some eminent scientists within the mineral research field, while admitting some advantages in the use of organic minerals, still advocate for the use of t sulphates over chelates. Their view is based solely around economics and the fact that organ storage (usually liver) for cattle receiving sulphates usually reaches adequacy levels. This view does not take into account the key role played by trace elements in achieving overall performance gains in both health and production, almost all of these advantages occur at the cell level, the fact the liver levels may indicate the animal is not technically deficient in the storage area it often has little relevance to performance in many of the key health areas. In order to unravel what is a very complicated picture it is important to recognize the different mechanisms of absorption and storage, these mechanisms are key to the difference between these two mineral types. When minerals are taken up from the soil they are naturally formed into protein/mineral bonds within the plant. Cattle will then graze that plant and ingest the mineral, not in straight elemental form, but instead as a combination of protein and mineral bound in a single molecule. Ultimately the protein and the mineral will be separately utilized by the body, however throughout the process of digestion and absorption the amino acid/mineral bond is never broken. The process effectively allows the amino acid to be absorbed directly to the cell with its mineral cargo still intact.

This is a much different process to that which occurs when a mineral is absorbed in inorganic (sulphate) form. Cattle grazing on pasture are always subject to a varying degree of soil ingestion, this is a small but relevant percentage of the total mineral requirement. This mineral is of course in inorganic form, the rumen is well equipped to handle these low levels and in fact they are necessary in order to feed rumen microbes. However large quantities of minerals ingested in this way can lead to real problems, for instance it is common to have antagonism between high levels of soil ingested iron causing deficiencies of copper, selenium, and vitamin E. When inorganic minerals are ingested they are subject to varying degrees of antagonism within the digestive system leading to much higher rates of excretion. High levels of freely available minerals in the rumen can also significantly slow rumen function. The body is programmed to get the majority of its minerals through foods by way of intestinal absorption. Due to potential cell toxicity related to unbound (inorganic) mineral forms, the body normally excretes them or rapidly locks them away in the liver until such time as they can utilized or safely excreted. Under certain conditions there can be a sudden release of these stored minerals from the liver, this can be potentially dangerous, particularly in the case of copper. Much of the research in the past has primarily looked at blood and liver storage levels in cattle, rather than tissue storage. This can be quite misleading as storage, particularly in the liver is often more directly related to mineral form than true efficacy. The limited research carried out to date indicates that liver levels can be high, even toxic, while animal performance and other signs indicate other tissues in the body are deficient, we are commonly seeing this with PKE use and copper. It is important to recognize the fact that unless the correct level of each particular mineral is present in each cell of the body, the animal is still technically deficient.

Minerals in plants and soils

These minerals appear in the soil as simple elemental mineral compounds, such as sulphates, chlorides and nitrates. Working alongside soil bacteria, plants are engineered by nature to make use of minerals in this form, however plants are not always that good at controlling absorption, therefore total uptake can be unpredictable. Although mineral absorption increases when there is a mineral shortage, and decreases when mineral levels are high, the plants mineral transport system often poorly regulates minerals that share the same or similar transport channels. For example, when copper and zinc are up-taken together, they compete with each other for transport into the plant, calcium and magnesium have similar issues.
An excess of zinc can often lead to a deficiency of copper, not necessarily because copper is not present but the fact is that an imbalance of the inorganic levels causes an antagonism to develop, negatively effecting plant uptake. If the purpose in using mineral fertilizers is to increase levels of specific elements within the plant, organic forms are a much better choice. The higher rates of use combined with the increased frequency of application can make the total cost of applying inorganic minerals higher when compared to the more available and flexible organic forms of the same element.

How does one isolate true chelates from the other mineral forms available in the marketplace which also quote superior availability?

Simply ask the following questions:
1 Is the product manufactured by a reputable company?
2) What is the chelating agent used in the product and at what concentration is the chelate?
3) Is the product masquerading as a chelate, when it is simply a blend of inorganic mineral and cheap protein powder?
4) What are the minerals chelated to, are the minerals tied to a cheap toxic chelation agent such as EDTA?
5) Can the manufacturer supply proof of the quality of the chelation bond within the product?
6) Is the product stable when subjected to various pH ranges? (pH 4.0 - 7.5)?
7) Is the resulting molecule small enough in size to allow unhindered movement through the cell wall?
8) Are there any animal or plant trials proving efficacy in use.
9) Compare pricing, label information, and product specifications carefully. You may well pay less for some supposed chelates and complexes, but are they the real thing? If the product is not truly a chelate then you are essentially buying inorganic minerals at a premium price. Without a guarantee of quality, you lose two ways, not just the money invested in the product but also the potential for productivity increases a quality product would deliver.

Only true amino acid chelates will deliver value for money.
Don't be fooled into paying good money for bogus product.

Agvance uses a range of mineral glycinates manufactured by BASF in Ludwigshafen, Germany. The technology involved in these mineral chelates is well proven in a large number of trials.