Don’t Overdose on Vitamin D can cause Magnesium Deficiency

Don’t Overdose on Vitamin D can cause Magnesium Deficiency

Vitamin D is a hot supplement right now, and for good reason. It’s super dark here in Canada. But today I’m going to explain why more Vitamin D is not better – and some of the real risks of over-supplementing this hormone.


Vitamin D is important for bone health, immunity, and possibly even for preventing depression.

If you aren’t getting 20 – 25 minutes of skin exposure daily (and by exposure, I mean more than just the tip of your nose), you may need vitamin D from diet or supplements.

Fatty fish, beef liver, egg yolks, some mushrooms, and fortified foods like certain brands of milk, juice and cereal contain vitamin D. As does cod liver oil. (Like that’s going to happen!)

We try to eat a plant-based, whole food diet, so most of these vitamin D foods just aren’t on our menu. Instead, we supplement.

But we do so carefully.


In The Magnesium Miracle, Dr. Carolyn Dean recommends no more than 1,000 – 2,000 IU of vitamin D daily – and importantly, she says to never take it without magnesium.


According to Dean’s research, high dose vitamin D actually depletes magnesium. That’s why some people on magnesium supplements still have symptoms of deficiency.

It’s not that their magnesium doesn’t work. It’s that their vitamin D intake is too high!

Here are two common scenarios:

  1. You’ve been taking magnesium and found relief from symptoms of deficiency. You then add in vitamin D, only to experience the stress, anxiety, tension, pain, sleeplessness, etc. you experienced before you found magnesium.
  2. You begin vitamin D supplementation without ever having taken magnesium and experience a whole suite of mystifying symptoms for the first time (Dean, p. Ixxvii).


“Magnesium is required to transform vitamin D from its storage form to its active form and for many other aspects of vitamin D metabolism.” (Dean, p Ixvii)

If you can tolerate technical details, here’s what else happens:

Vitamin D ‘grabs’ calcium from the diet and ‘holds onto it for dear life” (Dean, p. Ixxii). So calcium can accumulate, overriding magnesium and forcing it out of the body.

“In short” says Dr. Dean, “too much vitamin D can overutilize magnesium, block magnesium, purge magnesium, and propel people into magnesium deficiency.” (Dean, p. Ixxvii)

Dean also notes that vitamin D is actually a hormone, and suggests that it’s reckless to treat a hormone like a vitamin.

Hormones, she explains, ‘are regulated through a feedback system.’ In the case of vitamin D, there’s a feedback system with calcium. When we have enough calcium in the bloodstream, it natural for vitamin D levels to go down. (Dean, p. Ixxviii)


Go ahead and supplement with vitamin D in the darker months, or if you don’t get enough sunlight year-round. But keep your intake to a maximum of 2,000 IU. And don’t forget your Natural Calm magnesium.

That’s it for the health advice today! I hope there’s a bit of sun peeking over your shoulder, wherever you are.

Drop us a line here or on the Natural Calm Canada Facebook page with any questions or comments.


Dr. Carolyn Dean, The Magnesium Miracle, Revised and Updated. Ballantine Books, New York.


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