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Scientists discover why the body’s use of vitamin D is sub-optimal in half of all people in the West

Vitamine D Magnesium A newly-published study in The Journal of the American Osteopathic Association shows that the body may be unable to make proper use of vitamin D when magnesium levels are too low. And according to the researchers, that’s actually the case for 50% of the population in the West.

Vitamin D may therefore end up being uselessly stored in the body. This is a huge waste given that vitamin D deficiency has now reached epidemic proportions (see the compelling reasons for supplementing with vitamin D). The problem is that magnesium intake is just as bad: the study’s authors estimate that Western diets barely provide 50% of the recommended daily amount - 420mg for men and 320mg for women. Without adequate magnesium, the body cannot make proper use of the small amount of vitamin D circulating in the body (generated by exposure of the skin to the sun’s rays, or provided by the diet and supplements).

How is it that half the population is lacking in magnesium?

According to the study’s authors, magnesium deficiency is a relatively recent phenomenon, which may be the result of several factors:
  • Changes in eating habits: we’re consuming more and more refined, synthetic products that are low in micronutrients. Magnesium-rich foods, such as nuts and pulses, are gradually being side-lined.
  • Rising stress levels (1) and reduced sleep time which increase our requirements for magnesium. It seems our demanding lifestyles upset our nervous systems and more rapidly deplete our magnesium reserves.
  • Alcohol consumption (2) and disruption of the body’s acid-base balance which encourages the loss via urine of cations such as magnesium).
  • Certain diseases such as diabetes (3) and metabolic syndrome (4).
  • Taking medicines, particularly diuretics, antibiotics and PPIs (used for treating gastric ulcers and acid reflux) (5).

What other problems are posed by magnesium deficiency?

The importance of magnesium is rarely discussed yet it is essential in order for the body to function properly. In addition to its function in metabolising vitamin D, it is recognised for playing a number of fundamental roles:
  • Optimisation of the nervous system.
  • Supporting muscle and cardiac function (with a significant effect on blood pressure and on lowering the risk of cardiovascular disease and diabetes). Clinical studies show that taking a magnesium supplement may have antithrombotic effects (6) and help prevent atherosclerosis (7). Medical authorities in the US therefore recommend an elevated intake of magnesium to prevent and treat hypertension.
  • Maintaining healthy bones and teeth.
  • Involvement in more than 300 cellular mechanisms responsible for energy production.

How should we address this? What are the best sources of magnesium?

As the body is unable to produce magnesium itself, the options for rectifying magnesium deficiency are limited: we need to seek it out in food and take full advantage of high quality nutritional supplements. Obtaining sufficient magnesium from the diet is quite a challenge these days: it requires knowledge of its sources and constant awareness.

Here’s a recap of the best sources of magnesium to reintroduce to your diet as soon as possible.
Sources of elemental magnesium Portion Amount
1 OptiMag (supplement) 2 capsules 204 mg
2Pumpkin seeds 60 ml200 mg
3Brazil nuts60 ml 130 mg
4Cooked white beans 250 ml120 mg
5Magnesium Orotate (supplement) 3 gélules105 mg
6Roasted almonds 60 ml100 mg
7Cooked salmon 100 g100 mg
8Roasted cashew nuts 60 ml90 mg
9Pine nuts 60 ml85 mg
10Peanuts 60 ml85 mg
11Cooked spinach 125 ml80 mg
12Lentils and split peas 250 ml75 mg
13Soya yogurt 1 yogurt70 mg
14Quinoa 125 ml65 mg
15Potato including skin 1 medium50 mg

What is the ideal magnesium supplement?

When it comes to magnesium supplements, which are very convenient, it’s not the quantity but the quality that counts. Magnesium of mediocre-quality will not be fully absorbed by the body which may cause unwelcome symptoms, such as osmotic diarrhoea. This risk is increased when too much is taken in one dose (more than 400mg): the body is quickly overwhelmed and cannot absorb it all at once.

It’s therefore important to choose a form of magnesium with good bioavailability, good solubility and a moderate dose of the ‘magnesium element’, between 100mg and 250mg.

In order to produce magnesium supplements, a positively-charged magnesium ion (cation) must be combined with one that’s negatively-charged (anion). This forms a ‘magnesium salt’ or ‘magnesium oxide’. Magnesium salts can be organic (ie, they contain carbon, hydrogen and oxygen) or inorganic (these three base elements are absent). It’s worth emphasising that in general, organic salts are significantly more absorbable and useful to the body than inorganic ones.

Once it reaches the stomach, this combination salt disassociates as a result of the acidic environment, which allows the magnesium to pass through the cells of the intestine, to be used by the body. The greater its solubility – its ability to dissolve in the fluid milieu of the stomach - the more easily it reaches and passes through the gut mucosa.

A more stable complex can also be formed by binding a magnesium ion to a nitrogen-containing chelator. This produces chelated magnesium or amino-acid complexes. These supplements are more expensive to produce, but are generally absorbed best by the body. They don’t need to be soluble because they use the transport of proteins to pass through cell membranes.

Finally, it appears that certain magnesium salts, particularly magnesium lactate, magnesium sulphate and magnesium chloride, contribute to low level acidosis, ie, an upset in acid-base balance which is thought to result in loss of calcium and magnesium. In contrast, magnesium bicarbonate may be alkalinising. Currently, however, there is little scientific data to confirm this theory.

To help you make your choice, the following table, based on several studies (8-11), provides all the information you need on the properties and effects of the various types of magnesium supplement available:

Forms of magnesium Name Absorption Solubility Other effects
Organic salts Magnesium citrate GoodGood Alkalinising
Magnesium malate (available in supplement form as malate de magnésium) GoodGood
Magnesium lactate PoorAverage Acidifying
Magnesium aspartate GoodAverage Neuroexcitatory
Magnesium gluconate GoodAverage
Glycerophosphates GoodGood
Inorganic Salts Magnesium chloride AverageExcellent Acidifying
Magnesium hydroxide PoorLow
Magnesium carbonate PoorVery low
Magnesium bicarbonate PoorLow Alkalinising
Magnesium sulphate Poor LowAcidifying
Chelated forms of magnesium Magnesium orotate (available as supplément d’orotate de magnésium) Excellent Criteria not applicable
Magnesium glycinate Excellent Criteria not applicable
Magnesium lysinate Excellent Criteria not applicable
Magnesium oxide Magnesium oxide PoorAverage

You may find it simpler to take a combination of several different forms such as the product OptiMag. This well-known supplement contains magnesium malate, magnesium citrate and magnesium glycerophosphate, three forms which offer nothing but benefits. And since each capsule contains 102mg of magnesium, you can take one with each meal without risking any digestive problems.

Key points of the article

  • A lack of magnesium prevents the body from using vitamin D.
  • One in two people in Europe and the US have worryingly low levels of magnesium.

The study at the centre of the article

Anne Marie Uwitonze, Mohammed S. Razzaque. Role of Magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association, 2018; 118 (3): 181 DOI: 10.7556/jaoa.2018.037


1. Seelig MS. Consequences of magnesium deficiency on the enhancement of stress reactions; preventive and therapeutic implications (a review) J Am Coll Nutr. 1994;13:429–46. doi: 10.1080/07315724.1994.10718432.

2. Elisaf M, Merkourpoulos M, Tsianos EV, Siamopoulos KC. Pathogenetic mechanisms of hypomagnesemia in alcoholic patients. J Trace Elem Med Biol. 1995;9:210–4. doi: 10.1016/S0946-672X(11)80026-X.

3. Gommers LM, Hoenderop JG, Bindels RJ, de Baaij JH. Hypomagnesemia in Type 2 Diabetes: A Vicious Circle? Diabetes. 2016;65:3–13. doi: 10.2337/db15-1028.

4. Lima Mde L, Cruz T, Rodrigues LE, Bomfim O, Melo J, Correia R, et al. Serum and intracellular magnesium deficiency in patients with metabolic syndrome–evidences for its relation to insulin resistance. Diabetes Res Clin Pract. 2009;83:257–62. doi: 10.1016/j.diabres.2008.11.019.

5. de Baaij JH, Hoenderop JG, Bindels RJ. Magnesium in man: implications for health and disease. Physiol Rev. 2015;95:1–46. doi: 10.1152/physrev.00012.2014.

6. Shechter M, Merz CN, et al. Oral magnesium supplementation inhibits platelet-dependent thrombosis in patients with coronary artery disease. American Journal of Cardiology1999;84:152-6.

7. Kishimoto Y, Tani M, et al. Effects of magnesium on postprandial serum lipid responses in healthy human subjects. Br J Nutr. 2010 Feb;103(4):469-72. Epub 2009 Nov 27.

8. Coudray C, Rambeau M, Feillet-Coudray C et al (2005) Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach. Magnes Res Off Organ Int Soc Dev Res Magnes 18:215–223

9. Firoz M, Graber M (2001) Bioavailability of US commercial magnesium preparations. Magnes Res Off Organ Int Soc Dev Res Magnes 14:257–262

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

11. Dualé C, Cardot JM et al. An Advanced Formulation of a Magnesium Dietary Supplement Adapted for a Long-Term Use Supplementation Improves Magnesium Bioavailability: In Vitro and Clinical Comparative Studies, Biol Trace Elem Res. 2018 Mar 9. doi: 10.1007/s12011-018-1277-2.

Order the nutrients mentioned in this article

8 synergistic forms of magnesium for optimum bioavailability
New, more absorbable and better-tolerated formulation

Magnesium Orotate

Highly-bioavailable form of magnesium

Magnesium Malate

A patented form with improved bioavailability for chelating excess toxic aluminium
20% magnesium, 69% malic acid

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