Vitamin D, Magnesium, and Calcium are Co-Nutrients - Dr. Carolyn Dean MD ND

Vitamin D, Magnesium, and Calcium are Co-Nutrients

August 4, 2020

In medicine, we’re trained to be isolationists. We only focus on one disease, one drug, or one nutrient at a time. But that’s not how the body works. The dynamic interaction of nutrients is what keeps us alive and thriving.


For many years I was concerned that women were being asked to take poorly absorbed calcium supplements. I even wrote a blog called “Why I Hate Calcium.” Eventually, a number of papers by Dr. Boland in New Zealand showed that women who simply take calcium supplements are at a higher risk for heart disease. Other studies identified kidney stones, gall stones, heel spurs, atherosclerosis, and breast tissue calcification (DCIS) as being caused by calcium supplements. Various researchers over the years equated calcification with aging and we were doing that willingly to our patients. Because of my work with magnesium, I realized that calcium intake and unrecognized magnesium deficiency were driving calcification. 

I only recommend 600mg of calcium daily in food and/or supplements. Patients can identify their calcium dietary intake with the app and make up the difference with ReCalcia (300mg per tsp).


Calcium and magnesium have a dynamic relationship. As I say in my Magnesium Miracle book:

Magnesium and calcium antagonize each other in absorption, reabsorption, cell cycle regulation, inflammation, and many other physiologic activities. At the biochemical level, magnesium and calcium are known to act antagonistically toward each other. Many enzymes whose activities critically depend on a sufficient amount of intracellular magnesium (10,000 times more than calcium) will be detrimentally affected by small increases in levels of cellular calcium. Growth of cells, cell division, and intermediary metabolism are also absolutely dependent on the availability of magnesium, which can be compromised if excess calcium is present.

Vitamin D

My first exposure to high dose Vitamin D came as a question from a customer who had a 6-week migraine after eliminating them with ReMag. She thought her magnesium deficiency symptoms had come back and didn’t know why. Finally, she realized the migraine began after she took high dose Vitamin D and when she stopped it and continued her ReMag, her headache went away. When I looked into the relationship between magnesium and Vitamin D, I realized that magnesium is required to transform Vitamin D from the inactive, storage state to the active state. 

As practitioners became caught up in the Vitamin D craze, I received more and more complaints, so I began speaking out in blogs and my radio show about this interaction.

A picture is worth a thousand words and that’s the case with the flow chart displayed in the paper “Magnesium, Vitamin D Status and Mortality” in the BMC Medicine. The chart follows the many steps in vitamin D metabolism and shows that magnesium is required in 8 crucial steps.

This is vital information that every doctor prescribing vitamin D and every person taking vitamin D needs to know and needs to act on. Further, while the investigators called for more studies, their preliminary findings indicated that:

It is possible that magnesium intake alone or its interaction with vitamin D intake may contribute to vitamin D status.

Another study “Magnesium, Vitamin D Status and Mortality: Results From US National Health and Nutrition Examination Survey” found the following intriguing result: 

Our preliminary findings indicate it is possible that magnesium intake alone or its interaction with vitamin D intake may contribute to vitamin D status. The associations between serum 25(OH)D and risk of mortality may be modified by the intake level of magnesium.

Low Vitamin D and Low Magnesium Increase Risk

We know that low vitamin D increases the risk of mortality and morbidity and that magnesium plays an essential role in vitamin D metabolism. Putting these two facts together, researchers studied “The Association between Serum 25-Hydroxyvitamin D3 Concentration and Risk of Disease Death in Men: Modification by Magnesium Intake.”

This 2015 study included 1,892 men ages forty-two to sixty without cardiovascular disease or cancer. They concluded that low serum 25(OH)D3 concentration was associated with increased risk of death, mainly in those with lower magnesium intake.

The Dynamic between Vitamin D, Magnesium, and Calcium

Magnesium expert Andrea Rosanoff, Ph.D., understands the dynamic between vitamin D, magnesium, and calcium. She makes this the topic of her 2016 paper called “Essential Nutrient Interactions: Does Low or Suboptimal Magnesium Status Interact with Vitamin D and/or Calcium Status?”. Dr Rosanoff lists the problems encountered when trying to define this interaction in the paper’s abstract:

Although much is known about magnesium, its interactions with calcium and vitamin D are less well studied. Magnesium intake is low in populations who consume modern processed-food diets. Low magnesium intake is associated with chronic diseases of global concern [e.g., cardiovascular disease (CVD), type 2 diabetes, metabolic syndrome, and skeletal disorders], as is low vitamin D status. No simple, reliable biomarker for whole-body magnesium status is currently available, which makes clinical assessment and interpretation of human magnesium research difficult.

Additionally, Rosanoff recommends further study of the implications of low magnesium status with calcium and vitamin D:

Oral vitamin D is widely recommended in U.S. age-sex groups with low dietary magnesium. Magnesium is a cofactor for vitamin D biosynthesis, transport, and activation; and vitamin D and magnesium studies both showed associations with several of the same chronic diseases. Research on possible magnesium and vitamin D interactions in these human diseases is currently rare. Increasing calcium to magnesium intake ratios, coupled with calcium and vitamin D supplementation coincident with suboptimal magnesium intakes, may have unknown health implications. Interactions of low magnesium status with calcium and vitamin D, especially during supplementation, require further study.

I’ve known Dr. Rosanoff for many years and she has always stated, as she does in her abstract that “No simple, reliable biomarker for whole-body magnesium status is currently available.” 

I’m happy to say that my company, New Capstone Inc., is spearheading research not only on proving the high rate of absorption of ReMag, but on the superiority of ionized magnesium testing to be able to measure whole-body magnesium status. Our first research paper is entitled: “Circulating Ionized Magnesium as a Measure of Supplement Bioavailability: Results from a Pilot Study for Randomized Clinical Trial. A Placebo and Cross Over Blinded Control Study.” 

The Intricate Dance Between Magnesium and Calcium

The antagonistic relationship between magnesium and calcium is described by M. H. Tao in his paper “Associations of Intakes of Magnesium and Calcium and Survival Among Women with Breast Cancer” in which he states:

Magnesium and calcium antagonize each other in absorption, reabsorption, cell cycle regulation, inflammation, and many other physiologic activities.

Drs. Burton and Bella Altura in their 2001 paper note the interaction between calcium and magnesium. It’s called “Extracellular Magnesium Regulates Nuclear and Perinuclear Free Ionized Calcium In Cerebral Vascular Smooth Muscle Cells: Possible Relation To Alcohol and Central Nervous System Injury.” They blame a relative excess of calcium for the symptoms we may regard as magnesium deficiency.

Since magnesium is necessary to regulate calcium, when magnesium is deficient, it’s the excess calcium that creates vascular spasms and pathology.

That is why I consider a 1:1 ratio between magnesium and calcium as vital. 

When you acknowledge the complexity of the metabolic relationship between Vitamin D and magnesium; Vitamin D’s control of blood calcium; and the antagonistic relationship between calcium and magnesium, you can see how important all three co-nutrients are in partnership. If you recommend Vitamin D be sure to add the co-factor of magnesium in the highly absorbed form of ReMag.

Dosing Calcium, Magnesium, Vitamin D


I recommend that you begin slowly. From our research we determined that ReMag shows up on an ionized magnesium blood test within 2-4 hours. This confirms that one dose of ReMag is going to get into cells and begin working, so you don’t need a loading dose and you don’t have to wait days or weeks for it to start working.

Start with ¼ tsp per day in a quart of water and sip through the day. Every 2 days add another ¼ tsp. Work up to a therapeutic dose of 2-3 tsp a day if you are trying to overcome a health condition, if you are on medications or otherwise have magnesium deficiency symptoms

D3-K2 ReSet

Ideally you should obtain a GrassrootsHealth Vitamin D In Home blood test for Vitamin D and determine your dosage from their DCalculator. I had been taking Blue Ice Royal for Vit A, D, and K2 but when I got tested, my Vitamin D was only 19ng/dL. I took 10,000iu of plant lichen Vitamin D3 for 9 months and my test went up to 53ng/dL. I’ll keep up with the 10,000iu for another 6 months and recheck my levels. If they remain in the optimum range of 40-60, I’ll just continue with that dosage.


My recommendation for calcium is only 600mg, which is half of the U.S. RDA. The WHO and UK both recommend 500-700mg of calcium a day. It’s possible to obtain your daily calcium from diet – but only if you eat dairy products. You can check for the amount of calcium you are getting from your diet. If you require more calcium, take ReCalcia to reach 600mg.

About Dr Carolyn Dean

Dr. Carolyn Dean is a medical doctor and naturopath. She’s the author of over 35 books including best seller The Magnesium Miracle along with IBS for DummiesHormone BalanceDeath by Modern Medicine, and 110 Kindle books.

In 2011, she launched her RnA ReSet formulas through New Capstone and brought her 50 years of experience into her proprietary, unique formulations that give every individual at any stage of wellness or illness the necessary building blocks for sustained health, vitality, and well-being.

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