Magnesium What?: Navigating Mineral Forms

Magnesium citrate; magnesium glycinate, magnesium bisglycinate, magnesium taurate, magnesium oratate, magnesium amino acid chelate, magnesium oxide – the list goes on and on and you’ve still got chromium to grab after this. With all these different bottles staring back at you from the health food store shelf, you’d be forgiven for just picking one at random and getting the heck out of there.

But at some point you’ll probably wonder: what exactly are the differences between all these things?

The short answer is that you’re still getting the mineral you’re looking for no matter what the form. You’re getting calcium from calcium citrate or from calcium oxide. The different forms of these minerals differ by what the mineral ion is attached to. Put another way, the mineral form is defined by what it is “chelated” to.

The word, chelate comes from the Greek work “chele”, meaning claw. Chelate means to form a bond; in loose terms it means “bound to”. So the interaction of a metal ion and a single molecule is a chelation. You can think of the chelate as a claw binding the molecule to a mineral ion. Chelators in nutritional supplements for the most part include amino acids, organic acids, proteins, and occasionally more complicated chemicals.

Like with any nutritional component, the benefit of supplemental minerals are only as good as they are absorbed. If you’re not absorbing it, it’s not helping you (except for in rare cases, like when you’re using magnesium for its laxative properties). When a mineral ion is chelated to a molecule, it will go wherever that molecule goes. So a molecule that’s well absorbed will lead to a mineral chelate that’s well absorbed. It’s like a little biochemical hitchhiker.

So which form offers the best chance for optimal absorption? The short answer is one that doesn’t break down in the digestive process and can be absorbed quickly and easily across the gut wall into the blood stream. You see, sometimes mineral ions are bound to things that don’t form the tightest bonds. They’re weak chelates. To extend the hitchhiker metaphor, this essentially means that they might lose their ride when exposed to the acid, enzymes and agitation of the digestive process.

From there, they may be able to pick up another ride somewhere in the digestive tract from other foods that you’ve eaten, since the stomach allows for some chelation to naturally occur. Or the mineral ions may remain in ionic form (no chelate) and try to get absorbed as is, (ie. they may just try to walk instead of hitching a ride).

What are the different forms out there?

There was a time when people would only accept amino acid chelates as supplemental forms of minerals, the belief being that these were vastly superior to any other form. The logic makes sense; since the body already has a well established mechanism for absorbing amino acids across the gut wall, having an mineral atom on board as a hitchhiker just means it will get absorbed that much easier. But recent research has shown that other forms are also fairly easily absorbed. Some amino acid chelates include bis-glycinate, methionine, aspartate and taurate.

Sometimes you’ll see a supplement simply called an “amino acid chelate”. What this means is that they’ve simply added the mineral to a soup of different amino acids and let the minerals bind where they may. They haven’t chelated the minerals to a specific type of amino acid, but to many possible amino acids. This tends to be a cheaper way to go and there’s some controversy over how much of the vitamin content actually ends up chelated (generally, you get what you pay for here).

Other minerals are bound to organic acids like citrate, orotate, gluconate and picolinate. These constituents form relatively weak bonds with their mineral atoms. Therefore their activity as chelators to get the minerals absorbed through the digestive tract is only moderate since some of them inevitably “lose their ride”. That said, citrates, gluconates, plus picolinates and orotates in particular, have been studied and found to be proficient as mineral transporters.

What about food-form? Surely getting your minerals in the form we get it from in our foods would lead to the best absorption. Well, not necessarily.

In foods, minerals are most often found in inorganic salt forms (like carbonates, chlorides or sulfates). While it is accustomed to dealing with inorganic salt forms, the body’s system for transporting minerals can sometimes mis-regulate absorption for minerals that share the same transport channels. An example would be iron and calcium, or zinc and copper which compete for absorption through the same doorway. Food-forms may not be best at accomplishing higher-than-normal absorption minerals simply because it has to rely on these channels. It’s much easier to hitch a ride with another more easily absorbed compound.

There are other form of minerals for supplementation which I’m not going to go into much here. These include ionic forms and colloidal forms, which don’t tend to be very well absorbed. That’s not to say they don’t have their uses, but I’m not going to get into it here.

How much does all this really matter?

While the differences between some of the forms of mineral supplements may be minimal, there are sometimes consequences to taking a mineral in a form that’s poorly utilized by the body.

An example: headlines shocked the world recently when a meta-analysis found that those who supplemented calcium were more likely to have a heart attack. While the media ran with this as a means of demonizing all calcium supplements (and all supplements in general by extension), there was a more logical answer that went all but overlooked in the mainstream press.

Poor forms of calcium (like calcium carbonate, limestone or oyster shell and the much-hyped coral calcium) need to be chelated by the body before being absorbed. This requires a strong acid environment in the stomach. Combine using poor forms of calcium with an under-performing stomach, (as most stomachs are these days) and you’ve got a recipe for calcium that embeds in the tissues instead of in the bones.

Another example involves iron supplementation. Doctors most often prescribe ferrous sulfate, which is ironically a very poorly absorbed form of iron. This is why you see it in such massive quantities in these prescriptions (usually up around 300mg when the recommended daily amount is less than 30mg); since so little of it is absorbed. All that ferrous sulfate that doesn’t get absorbed ends up causing gastrointestinal distress like constipation.

So which form is the best?

This is a question I hear about ten times per day. The answer isn’t simple, but to put it simply: it depends. Mostly it depends on what your goals are. If you’re simply looking to increase your exposure to a certain mineral for general health, the form may not be all that important, as long as it has a good affinity for getting absorbed. But if you have a specific condition you’re targeting, specific forms may be more desirable.

It’s important to remember that there isn’t a lot of research comparing various mineral forms and their absorption tendency. What research is out these suggests that the inorganic mineral salts (food-forms) are sufficient for correcting general deficiencies. However, more specialized sources may be needed for correcting disease-caused deficiencies and for bypassing the mineral regulators of the body to get more minerals into the cells than they naturally would achieve on their own. Amino acid chelates seem to be the best at achieving these purposes followed by organic salts; picolinates and orotates in particular.

The most important take-away from this is that the differences in mineral forms are important and should be researched appropriately. The best way to do that is to consult with a natural health care practitioner who will be able to make recommendations based on your particular case. 


By Doug DiPasquale, Certified Holistic Nutritionist