Which magnesium supplement is best and for who?

Posted on Tue, 24 Sep 13

Magnesium deficiency is associated with a remarkably wide range of illness from asthma, to cardiovascular disease, diabetes, migraines, and depression (1). A magnesium supplement is a safe, effective way to top up your levels and relieve symptoms but which dietary supplement is best?

Most people do not achieve the recommended daily intake of magnesium (320-420 mg) through their diet; in fact the last national diet and nutrition survey found that, on average, nobody was getting enough (2). Increasing your dietary intake is important but while you are eating more magnesium rich foods you may want to consider a magnesium supplement.

Table 1: Magnesium Rich Foods

Food	Serving	Magnesium (mg)
Brown rice	1 cup cooked	86.0
Almonds	1 ounce (23 almonds)	78.0
Hazelnuts	1 ounce (21 hazelnuts)	46.0
Lima beans	½ cup cooked	63.0
Spinach, chopped	½ cup cooked	78.0

There are many magnesium containing nutritional products available, so which to choose? How well it is absorbed (bioavailability) and the type of magnesium may help you decide.

Is one type of magnesium really better than another?

There are several different types of supplemental magnesium available (e.g. citrate, orotate, malate, oxide, and sulphate). Unfortunately bioavailability studies typically compare just a few types of magnesium and none directly measure absorption, instead often using urinary magnesium excretion as an indirect marker of bioavailability, which is not very accurate.

Here are the bioavailability studies to date:

• Lindberg et al (1990) demonstrated greater bioavailability from a single dose of magnesium citrate versus magnesium oxide (3).
• Muhlbauer et al (1991) found magnesium aspartate superior to oxide (3).
• Schuette et al (1993 & 1994) did not find a difference between magnesium glycinate and magnesium oxide (5,6).
• Firoz & Graber (2001) revealed a relatively poor bioavailability of magnesium oxide when compared to magnesium chloride, lactate, and aspartate (7).
• And Walker et al (2003) found magnesium citrate to be superior to a glycinate and oxide (8).

Interestingly, although magnesium oxide has generally been found to have poorer absorption a recent study by Schecter et al (2012) discovered that magnesium oxide was superior to magnesium citrate both in terms of bioavailability and health benefits (9). This well conducted and more recent study challenges the assumption that magnesium oxide is inferior.

So as the current science stands there is not sufficient evidence to suggest one form of magnesium is superior to another in terms of bioavailability, in fact clinical studies have generally found a variety of forms (in particular carbonate, chloride, citrate, orotate and oxide) able to correct deficiency and clinically effective for a wide range of illness (10). Perhaps any difference in absorption between various types of magnesium is not that meaningful in terms of actual benefits.

Magnesium is only half the story

An underappreciated factor in magnesium supplementation is the “other half.” Magnesium is typically bound to another molecule, such as citric acid in the case of magnesium citrate, and a number of these secondary molecules have important biological effects that may help guide the selection of a suitable magnesium formulation. Here are the three best examples:

Magnesium orotate: healing the heart  

Orotic acid is the other half of magnesium orotate, and has been shown to have important biological and clinical benefits for cardiovascular health. A naturally occurring dietary acid, orotic acid is an intermediate in the synthesis of cellular energy and has been shown to enhance energy production in the heart amongst other unique biological effects (11).

Magnesium orotate has been well studied and used as a “cardiovascular drug” in Russia since the 1970s. A number of more recent human clinical studies support this unique application of magnesium orotate with evidence that supplementation may improve exercise tolerance in patients with coronary artery disease, improve ventricular function, and significantly increase survival rate and improve clinical symptoms and quality of life in congestive heart failure (12,13).

Magnesium glycinate: sweet dreams

Glycine is complexed with magnesium to form the amino acid chelate magnesium glycinate. Glycine has interesting effects in the central nervous system where it augments N-methyl-D-aspartate (NMDA) receptor-mediated neurotransmission and functions as an inhibitory neurotransmitter via the glycine receptor (14). These effects may result in a calming, relaxant effect and could explain why glycine helps people sleep better.

Glycine may be useful for insomnia. Two human clinical studies have shown that 3 grams of glycine taken before bed can improve sleep and reduce daytime drowsiness (15). A typical tablet or capsule of magnesium glycinate will provide 100 mg of magnesium and 900 mg of glycine so try 3 taken an hour before bed.

Magnesium malate: pain relief

Malic acid, bound to magnesium to form magnesium malate, is an intermediary in the Krebs cycle and involved in energy metabolism. Dr Gee Abraham first hypothesised that fibromyalgia syndrome may be due to a defect in cellular metabolism characterised by low ATP production (leading to the characteristic symptoms of fatigue) and a build up of organic acids (explaining the diffuse muscle pain). Supplementation with magnesium malate – to provide magnesium for acetyl-CoA synthesis and malic acid for malate dehydrogenase activity – may be able to improve energy metabolism and relieve fibromyalgia, he theorized. 

In an open label study to test this hypothesis Abraham et al (1992) reported that oral treatment with magnesium malate (300-600 mg magnesium and 1200-2400 mg malate daily) for 8 weeks improved fibromyalgia pain (16).  A follow up placebo controlled trial however failed to demonstrate benefit but this may be due to a shorter treatment duration (4 weeks) and lower dose (300 mg magnesium and 1200 mg malate daily) (17).

Get a magnesium top up

According to clinical studies a typical dose of magnesium is 300 mg once to twice daily and should be continued for at least 3-4 months to notice benefits. Choosing a particular type of magnesium such as orotate, glycinate or malate may have some added benefits. When selecting a product make sure you place quality first.

References:

1. Johnson S. The multifaceted and widespread pathology of magnesium deficiency.  Med Hypotheses. 2001 Feb;56(2):163-70.

2. Henderson et al (2002) National Diet and Nutrition Survey: adults aged 19 to 64yrs. The Stationary Office. London

3. Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from  magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990 Feb;9(1):48-55.

4. Muhlbauer B. Schwenk M, Coran WM et al. Magnesium-L-aspartate-HCL and magnesium-oxide: bioavailability in healthy volunteers. Eur J Clin Pharmacol 1991; 40: 437-438.

5. Schuette SA, Lashner BA, Janghorbani M. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN J Parenter  Enteral Nutr. 1994 Sep-Oct;18(5):430-5.

6. Schuette SA, Janghorbani M, Young VR, Weaver CM. Dysprosium as a nonabsorbable marker for studies of mineral absorption with stable isotope tracers in human subjects. J Am Coll Nutr. 1993 Jun;12(3):307-15.

7. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001 Dec;14(4):257-62.

8. Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003  Sep;16(3):183-91.

9. Shechter M, Saad T, Shechter A, Koren-Morag N, Silver BB, Matetzky S. Comparison of magnesium status using X-ray dispersion analysis following magnesium oxide and magnesium citrate treatment of healthy subjects. Magnes Res.  2012 Mar 1;25(1):28-39.

10. Braun & Cohen. Magnesium, in Herbs and Natural Supplements, 3rd Edition. Churchill Livingstone Australia, 2011.

11. Classen HG. Magnesium orotate--experimental and clinical evidence. Rom J Intern Med. 2004;42(3):491-501.

12. Rosenfeldt FL. Metabolic supplementation with orotic acid and magnesium orotate. Cardiovasc Drugs Ther. 1998 Sep;12 Suppl 2:147-52.

13. Stepura OB, Martynow AI. Magnesium orotate in severe congestive heart failure  (MACH). Int J Cardiol. 2009 Jan 9;131(2):293-5

14. Rajendra S, Lynch JW, Schofield PR. The glycine receptor.  Pharmacol Ther. 1997;73:121–146

15. Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. J Pharmacol Sci. 2012;118(2):145-8.

16. Abraham GE, Flechas JD. Hypothesis: Management of fibromyalgia: rationale for the use of magnesium and malic acid.  J Nutr Med 1992;3:49-59.

17. Russell IJ, Michalek JE, Flechas JD, Abraham GE. Treatment of fibromyalgia syndrome with Super Malic: a randomized, double blind, placebo controlled, crossover pilot study. J Rheumatol. 1995 May;22(5):953-8.