magnesium for strong bones, magnesium supplement, vitamin D level

People with a low vitamin D level may benefit from increasing their magnesium intake. The relationship between these two nutrients is more complex than you might think, however.

Vitamin D Level Dips in Winter:

At this time of year, vitamin D levels drop due to limited sun exposure. Doctors sometimes recommend vitamin D pills to compensate for this predictable dip. But people with low levels of magnesium in their bodies may not get the boost they need from vitamin D supplements. Magnesium is a critical component of enzymes that metabolize vitamin D in the body.

According to the National Health and Nutrition Examination Survey, 79 percent of adults in the U.S. are not getting the recommended dietary allowance of this mineral. Rich sources of magnesium such as green leafy vegetables, nuts, beans and whole grains are not staples of everyone’s diet. Assessing the body’s stores of magnesium is not simple, however, and magnesium levels are rarely tested.

A Placebo-Controlled Trial:

A randomized controlled trial of 180 people compared the effects of magnesium supplements and placebo on vitamin D level (American Journal of Clinical Nutrition, Dec. 1, 2018). The dose of both magnesium and placebo was individualized to compensate for dietary intake of magnesium.

The Results Varied According to Vitamin D Level:

The investigators measured 25-hydroxyvitamin D3 in the participants’ blood. This is a standard technique for assessing circulating vitamin D. A number of the volunteers had a vitamin D level at or below 30 ng/ml. Vitamin D is considered insufficient at a level of 20 ng/ml. Other participants had 25-hydroxyvitamin D measured between 30 and 50 ng/ml.

Among people with high levels of vitamin D (between 30 and 50), magnesium supplements tended to lower them. On the other hand, magnesium supplements boosted vitamin D levels in people who started out low, below 30 na/ml.

The researchers concluded:

“optimal magnesium status may be important for optimizing 25(OH)D [25-hydroxyvitamin D] status.”


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  1. Saibal
    The Netherlands

    As I’ve pointed out here:

    sticking to whole foods should yield about twice the RDA of magnesium. If you stop using refined oils, butter etc. and instead get your fats from nuts and seeds and eat only whole grain carbs, then a 2500 Kcal diet will yield at least 0.7 grams of magnesium.

  2. Bob
    Spokane, WA

    A bit confusing for me. You say between 30-50 ng/ml is the amount of D we should have. I’ve been taking Costco “D3 and per capsule is 125 mcg. Is that enough? Too much?

  3. frank
    toano va

    Still looking for help on raising white blood cells; need for continuing with chemo

  4. Jampot

    I just purchased and downloaded the “Vitamin D Deficiency” guide and can find no reference to magnesium supplements. Based on today’s Health Headlines email, I expected to read more about the impact of magnesium supplementation and whether I’m taking too much. The copyright date on the guide is shown as 2010 but it would be helpful in this fast-changing world of medicine if the latest change date was listed on all the People’s Pharmacy Health Guides.

  5. Nancy

    I don’t tolerate magnesium supplements very well and am going to try magnesium spray. Is there any research to determine if this is a viable option?

    • Jeannette

      yes spray is available just google it.

  6. Sharon
    Tucson AZ

    Perhaps this explains the findings of the latest research on the levels of vitamin D, Calcium and Osteoporosis. Supposedly, supplementing the patients’ diets with both had little impact on reducing the severity of the disease. Did the researchers verify that the participants had optimal magnesium and vitamin D levels?

  7. Lida

    But what is optimal magnesium supplement?
    I would like to know your take on what vitamin D level is optimal since I read so many different views. My doctor says 32 is fine but have read that it is important to have a much higher level.

    • Terry Graedon

      There is not perfect consensus on this, but many experts suggest that levels of 25-hydroxyvitamin D between 30 and 50 ng/ml are optimal or close to it.

  8. Luke

    KNOW YOUR KIDNEY FUNCTION. You can easily go into magnesium toxicity if your creatinine clearance is low or if you have other kidney issues. Even taking Milk of Magnesia can be dangerous with poor kidney function.

  9. Robert

    Interesting & intriguing study. However, the study only takes into account the storage form of Vit. D 25 OH. In order to see the big picture it should also include the active form of D which is the 1.25 OH.

    • Terry Graedon

      The study actually did look at the various forms of vitamin D, including 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 as well as 1,25-hydroxyvitamin D. But I’m not clear enough on how to explain the significance in our report.

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