Oral magnesium supplements

What makes a good ORAL magnesium supplement?

We take a magnesium supplement for its magnesium ions (mg++)

(1) Bioavailability

This subject of Mg bioavailability has been quite challenging!   There are few pertinent human studies (of which, participant numbers are low and many are carried out by manufacturing companies with a bias for their own product; veterinary studies used animals on mineral-deficient diets, which slants results) and there are many factors involved in the body that reduce or encourage the metabolic utilization of a nutrient; also,  I didn't put much stock in the rat or cow studies, since our digestive systems are so different and the variable conditions in our gut are strongly affected by our diet.

A good ORAL magnesium supplement is one that is absorbed effectively through the intestinal wall into the bloodstream / lymph in a form utilizable by the body's cells.    The magnesium ions in a good magnesium supplement molecule must be able to be separated (dissociated) from its companion (ligand). Eg. In magnesium oxide (MgO), the mg++ ion must be separated from its oxygen ion, or in magnesium citrate, from the citric acid.

-    Magnesium supplement must be soluble to enable release of its elemental magnesium content from its "traveling companion".  However, once separated from the ligand substance it is bonded to, the magnesium ion may meet and bond with drugs or phytates, oxalates, phosphorus, carbs, fats or amino acids in food. Phytates bind strongly to magnesium (also calcium, iron, zinc, selenium, chromium and manganese) making it near impossible to separate the magnesium ion for absorption. The main benefit of the medium strength bonds of such as amino acid chelated magnesium, seems to be in preventing magnesium making stronger bonds with other binding agents, such as phytates, but still having weak enough bonds to separate for intestinal absorption over the several hours it travels along the GI tract. It is also postulated (as yet no studies) that the chelated magnesium amino acid molecule may be absorbed intact.

Note: while consumed oxalates (in spinach, rhubarb, french fries, bran flakes, nuts) tend to bind with magnesium,  current studies do NOT support their negative effect on magnesium absorption

-   Take magnesium supplement away from phytic acids in foods.   This prevents their almost inseparable binding of the magnesium ion in the intestine, thereby making magnesium unavailable for absorption through the gut wall. You do not need to concern yourself about phytic acid consumption if you are taking an amino acid chelated form of magnesium, which prevents phytic acids from bonding to magnesium ions.

-   Ensure a sufficiency of vitamin D.   This  has been shown to improve magnesium absorbability; best obtained by taking a daily sunbath.

Vitamin D -The Sunshine Vitamin

 -   Split high daily doses.   100-200 mg at a time work more efficiently; Do not take more than 300-400 mg. of an oral Mg supplement at one time, which may result in diarrhea.

-    Take magnesium supplement with a meal, but not one containing phytic acid (see above).   Many magnesium supplements (but not chelated forms) need stomach acid to help separate magnesium ion from its companion substance.   Although eating food stimulates stomach acid production,  HCl production tends to decrease with age and since the break down of the molecule is key to effective digestion, it may be necessary to take a betaine hydrochloric acid supplement to better utilize dietary and/or supplementary magnesium or other nutrients. Avoid drugs/antacids that reduce or prevent stomach acid production.  

-    Avoid the many factors that cause magnesium loss or reduce its absorption:

  Why are we magnesium deficient?

-   Carbohydrates, such as fructose and fermentable carbohydrates (comprised of short-chain sugar molecules) improve magnesium absorption by feeding intestinal bacteria.    E.g. bananas, plums, 

-   Don't use enteric-coated (time-release) tablets.    Studies have shown time-release tablets are less absorbed than immediate release supplements. The tablet must be able to disintegrate / dissolve in time for effective absorption in the intestines. Fine 1991,Ricketts 1993, Rudinskas 1989, Walker 1989

(2) Percentage of magnesium in the supplement molecule

DIfferent magnesium supplements contain different amounts elemental magnesium in their molecules.    E.g. magnesium oxide is 59% elemental magnesium; magnesium citrate is 16%, magnesium orotate is 6.2%, magnesium gluconate is 5.5%;

However, the bioavailabilty of each form can be very different and has to be taken into consideration;

(3) Is there any benefit or harm from the magnesium "companion" substance?

For example:

Magnesium Glutamate and Aspartate may be neurotoxic

(4) Cost

How much magnesium to take?

How much magnesium should I take?

What form of magnesium to take?

Main recommendations for an ORAL magnesium supplement

Prefer Transdermal Magnesium Chloride :)    Not as convenient as an oral supplement, but fast acting and very boioavailable;

Still researching whether one form of magnesium over another is best for oral use; getting close with my conclusions :) For the moment a chelated form of TRAACS ® magnesium bisglycinate (buffered) is recommended for both availability and cost-effectiveness, such as  Albion Magnesium sold by Swanson's

Forms of magnesium to stay away from

Magnesium Glutamate and Aspartate supplement forms may be neurotoxic

References

Fine KD, Santa Ana CA, Porter JL, Fordtran JS. Intestinal absorption of magnesium from food and supplements. J Clin Invest 1991;88:396-402.

Ricketts CD. Iron bioavailability from controlled-release and conventional iron supplements. J Appl Nutr 1993;45:13-19.

Rudinskas L, Paton TW, Walker SE. Poor clinical response to enteric-coated iron preparations. Can Med Assoc J 1989;141:565-6.

Walker SE, Paton TW, Cowan DH, et al. Bioavailability of iron in oral ferrous sulfate preparations in healthy volunteers. Can Med Assoc J 1989;141:543-7.