Sunday, August 11, 2013

Magnesium--A Key Mineral in Human Metabolism

Magnesium (Mg) is one of the most important nutrients in your body. It is involved in cell energy
Magnesium's central position in the chlorophyll molecule
metabolism, muscle tone (including heart contractions), nerve conduction, cell membrane formation and maintenance, electrolyte balance, enzyme function, and in biological mechanisms that protect you from the damaging effects of inflammation and free-radicals. Magnesium is also absolutely vital for good bone health. It is used by osteoblasts to build new bone and it is necessary for the production of bone-regulating calcitonin and parathyroid hormones. Magnesium is also important for preventing calcium from depositing into soft tissues.

Unfortunately, magnesium deficiency is common, and more so in older adults. In fact, it has been estimated that up to 80 percent of elderly individuals are deficient in magnesium. Magnesium can be difficult to absorb and as we age reduced digestive capacity lowers absorption further. Stress and disease also contribute to increased magnesium demands.

Signs of magnesium deficiency can include muscle spasms, skin twitching below the eye, constipation, hypertension, rapid heart rate, arrhythmias, depression, fatigue, asthma, muscle weakness, irritability, and hypersensitive skin.

How can you know for sure if you have magnesium deficiency? The gold standard lab test for determining magnesium levels is to evaluate the levels in red blood cells. (Blood serum testing is not a good indicator for magnesium because most (99%) of this mineral is stored within cells and not in the extracellular fluids.) In addition, because deficient magnesium can affect many systems throughout the body, other lab results may alert the physician (or you) that a red blood cell analysis of magnesium is indicated. The following labs are the most helpful:

-  Low serum calcium.
-  Low serum potassium
-  Low active vitamin D or calcitriol [1,25(OH)2D]
-  Elevated parathyroid hormone (PTH)
-  Low osteocalcin
-  Elevated C-reactive protein (hs-CRP)

It pays to ensure that you get adequate magnesium before signs of deficiency occur. Your best sources of dietary magnesium are found in whole grains, seeds, nuts, and especially in green vegetables (Notice the central position of the magnesium ion in the chlorophyll molecule in the picture...chlorophyll is what gives plants their green color and the ability to absorb energy from light.) But magnesium supplementation (300 to 600 mg/day), especially if you have bone loss, is usually a good idea. I've always touted the virtues of high-end magnesium sources such as what I use in our OsteoNaturals products. OsteoSustain is formulated with Albion's TRAACS magnesium glycinate chelate and our OsteoMineralBoost has dimagnesium malate. Both of these forms of magnesium are known for their superior absorbability and effectiveness.

I have always complained about vitamin-mineral products that used magnesium oxide and felt that they were inferior. Well...not so fast...I may have to eat my words. Research by Shechter et al. recently demonstrated that supplemental magnesium oxide was actually superior to magnesium citrate for increasing intracellular magnesium levels. Magnesium oxide also appeared to be more effective in reducing hs-CRP. This is pretty impressive so, even though there are some limitations* to this study, I will go a bit easier on magnesium oxide from now on. I'm not thoroughly convinced, but at least I will not object so vehemently.

     * My concerns about this study:  The author's choice to use x-ray dispersion analysis
      for measuring intracellular magnesium is not your standard testing method. In my
      opinion, it would have been better to have included the tried-and-true red blood cel
      l analysis in the study for comparison. Secondly, one of the authors of the study is
      the Research Director and President of IntraCellular Diagnostics, Inc., the company
      that uses this form of magnesium testing commercially. And finally, the researchers
      used two different dosages of magnesium products for their comparison: Diasporal
      (magnesium citrate) has 295.8 mg of elemental magnesium while Magnox
      (magnesium oxide) has 520 mg of elemental magnesium. This is a huge discrepancy
      and one that may indeed invalidate the study.

Shechter M. et al. 2012. Comparison of magnesium status using X-ray dispersion analysis following magnesium oxide and magnesium citrate treatment of healthy subjects. Magnesium Research 25(1):28-39.   

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