Labels for supplements can be confusing.
They may give data and it is not clear for example, that you have to take
2-4 tablets to get the amount on the supplement listing. One must read all supplement nutritional labels carefully and not assume they refer to one tablet unless that is listed as such.
Another confusing issue is the concept of ELEMENTAL.
This is very important for minerals: calcium, magnesium, zinc are good examples.
Basically magnesium is a metal, and in its pure form, it is not soluble in water.
Mixed with various other molecules or compounds(chelates), it becomes more
accessible to the body and can be used properly.
It can be mixed with an inorganic molecule:
magnesium oxide
magnesium sulfate
magnesium chloride
OR it can be mixed with an organic compound--usually an amino acid--
which then makes it more absorbable..These are called chelates.
The chelate weighs more than the magnesium and hence the total actual percentage of magnesium itself is lower compared to the weight of the mixture.
The general ratio of magnesium to total chelate weight varies from 8% (for the taurate) to about 12% for some others. One guideline is size. If the tablet label for a chelate is confusing and does not give "elemental" values,
and the tablet is small...don't expect much magnesium. For example magnesium malate is 152mg of magnesium elemental, and 848 mg of malic acid to give a total weight of 1000mg on the label. And it is a huge tablet reflecting that ratio.
This website explains it too:
http://ods.od.nih.gov/factsheets/magnesium.asp
Quote:
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Oral magnesium supplements combine magnesium with another substance such as a salt. Examples of magnesium supplements include magnesium oxide, magnesium sulfate, and magnesium carbonate. Elemental magnesium refers to the amount of magnesium in each compound. Figure 1 compares the amount of elemental magnesium in different types of magnesium supplements [28]. The amount of elemental magnesium in a compound and its bioavailability influence the effectiveness of the magnesium supplement. Bioavailability refers to the amount of magnesium in food, medications, and supplements that is absorbed in the intestines and ultimately available for biological activity in your cells and tissues. Enteric coating of a magnesium compound can decrease bioavailability [29]. In a study that compared four forms of magnesium preparations, results suggested lower bioavailability of magnesium oxide, with significantly higher and equal absorption and bioavailability of magnesium chloride and magnesium lactate [30]. This supports the belief that both the magnesium content of a dietary supplement and its bioavailability contribute to its ability to replete deficient levels of magnesium.
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There is a nice chart on this website to help you understand.
The second part of understanding magnesium supplements is understanding
bioavailability..that is after you swallow the tablet, how much can one expect to be absorbed and become useful to the patient.
New evidence has shown the the traditional form, magnesium oxide, is not bioavailable.
Quote:
Magnes Res. 2001 Dec; 14(4): 257-62. Related Articles, Links
Bioavailability of US commercial magnesium preparations.
Firoz M, Graber M.
Department of Veterans Affairs Medical Center, Northport, NY 11768, USA.
Magnesium deficiency is seen with some frequency in the outpatient setting and requires oral repletion or maintenance therapy. The purpose of this study was to measure the bioavailability of four commercially-available preparations of magnesium, and to test the claim that organic salts are more easily absorbed. Bioavailability was measured as the increment of urinary maginesium excretion in normal volunteers given approximately 21 mEq/day of the test preparations. Results indicated relatively poor bioavailability of magnesium oxide (fractional absorption 4 per cent) but significantly higher and equivalent bioavailability of magnesium chloride, magnesium lactate and magnesium aspartate. We conclude that there is relatively poor bioavailability of magnesium oxide, but greater and equivalent bioavailability of magnesium chloride, lactate, and aspartate. Inorganic magnesium salts, depending on the preparation, may have bioavailability equivalent to organic magnesium salts.
PMID: 11794633 [PubMed - indexed for MEDLINE]
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Unfortunately, many doctors still consult outdated manuals when prescribing magnesium supplements...and the old oxide persists in their minds.
So I have printed that study here, so interested patients can copy it and take to their doctor. Many people believe that 400mg of magnesium oxide is alot, but in reality only 8mg is actually absorbed..which is very little. That is the lowest reported figure for
low magnesium containing foods-- one apple, one hard boiled egg, or 1oz of cheddar cheese.
High foods include almonds
3oz=270mg, 1 cup of oatmeal=57 mg, and 1 cup of navy beans=108mg.
Recently I just looked up magnesium products on Puritan's Pride website, and saw some updating in the labeling. This is a very good trend and will help avoid confusion. I hope some other products follow this lead.
One sign that you are not getting your magnesium from your chosen product is loose stools or frank diarrhea. That means the magnesium is remaining in the GI tract, and creating a laxative effect. Either change products or lower the dose used. However, many people do not get diarrhea, especially if they are prone to constipation. Sometimes, they just seem "normal" instead. Others who are more prone to looseness will notice any little extra magnesium.
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All truths are easy to understand once they are discovered; the point is to discover them.-- Galileo Galilei
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Weezie looking at petunias 8.25.2017
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These forums are for mutual support and information sharing only. The forums are not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider. Always consult your doctor before trying anything you read here.