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Vitamin D and Magnesium Interconnectedness

October 12, 2014 | 10 Comments | SAFM Team

Magnesium is required to convert Vitamin D into its active form in the bloodstream.  As a result, Vitamin D supplementation (especially  high-dose) may actually cause or exacerbate magnesium deficiency.  It can be an major disruption in your quest to create a wildly-satisfied client if someone who begins using  a Vitamin D supplement suddenly starts having muscle cramps, acid reflux, constipation, or headaches!  You will also want to look for this connection in your new clients given their prior labwork and their symptom checklist.  You may find this or this interesting.

When your clients and patients seek to understand their Vitamin D level, encourage them to request an “RBC magnesium” (vs. serum magnesium) level at the same time.  As with all mineral labwork, it is best to aim for the upper third of the reference range, given the high incidence of mineral nutrient deficiencies.  Remember that RBC mineral levels better reflect ongoing nutrient levels over a 3-4 month time period (vs. typical serum levels which only reflect dietary/supplement intake for the past few days at most).

In the absence of labwork (and assuming no overt kidney disease), I recommend including magnesium supplementation when a client is using a Vitamin D supplement, especially if it’s more than 1000 IU daily of Vitamin D3 (higher levels of which most of our clients will need from October through April).

I recommend magnesium glycinate for most of my clients who need to increase their magnesium, ~300mg with food, either once or twice daily.  For constipation, magnesium citrate is a preferred form.  We have talked about magnesium at length in prior clinical tips.  RBC magnesium can be checked 4-6 months after taking a consistent supplement dose to see if it is sufficient.

Because magnesium deficiency is particularly common in your diabetic clients, this is a secondary consideration to keep in mind with these clients.  You may find this interesting.

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10 Questions for “Vitamin D and Magnesium Interconnectedness”

  1. 5
    Mandy Vaughan says:
    October 4, 2023 at 4:15 pm

    What would be the best journal article you would recommend for the relationship between Magnesium and Vitamin D/the information listed above?

    Reply
  2. 4
    Jodie Black says:
    October 25, 2021 at 12:18 am

    Do you have take Vitamin K2 with vitamin D3 to prevent calcium build up in arteries and for better absorption of vit D3? If so, can you get enough Vit K2 from diet or is supplement necessary

    Reply
  3. 3
    Melissa Lee says:
    June 7, 2020 at 8:01 pm

    I read this in a paper about subclinical Mg deficiency :
    over-supplementing with vitamin D may lead to magnesium deficiency via excessive calcium absorption
    and hence increase the risk of arterial calcifications.

    Is it because vitamin D increases calcium absorption into bone and tissue?

    Reply
    • 3.1
      SAFM Team says:
      June 9, 2020 at 10:04 pm

      There are a couple of points here that might be helpful. (1) As is the case with many minerals, magnesium and calcium compete for absorption at both the gut and the cellular level in many cases. Check out the Introduction in this research article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2082111/ (2) Vitamin D increases calcium absorption from the gut into the systemic body. Once absorbed, magnesium is required to convert Vitamin D to its final form that the body uses for cellular effects; this is true whether the D is made endogenously from sun exposure or taken via supplement. So over-supplementing D can not only bring on too much absorption competition from calcium but can also require so much of the body’s limited supply of magnesium that insufficient levels are remaining for a rich variety of other systemic purposes, including supporting bone mineralization.

      Reply
  4. 2
    CAROLINA CILIBERTO says:
    March 29, 2020 at 4:04 pm

    I understand RBC Magnesium represents the real status of Magnesium in the body vs serum Magnesium which represents more of the Magnesium that was consumed in the last few days. But what about urine Magnesium? is it representative of the sufficiency of this mineral in the body? I ask because where I live there are no laboratories ofering RBC Minerals Tests…which Marker should I use for Magnesium?

    Reply
  5. 1
    Joan Zietlow says:
    December 24, 2015 at 3:05 am

    Are there two different reference ranges for RBC magnesium? I mean is there a typical lab range and then a functional range? In some of the noted studies they seem to quote the average range of the study participants and not include the functional or average lab range. Can you address this please? Thank you.

    Reply
    • 1.1
      SAFM Team says:
      December 29, 2015 at 7:14 pm

      Generally speaking (at least in the US), quoted, standard lab ranges are going to be statistical norms. That is, a range of what 90-95% of the representative population actually has (without assertion as to what is ideal or even healthy). Functional or “healthy ranges” are seldom cited by labs and are arrived at rather via clinical study and clinical practice given patient population responsiveness.

      Reply

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