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Low magnesium levels make vitamin D ineffective

American Osteopathic Association

vitamin D

Vitamin D can't be metabolized without sufficient magnesium levels, meaning Vitamin D remains stored and inactive for as many as 50 percent of Americans. In addition, Vitamin D supplements can increase a person's calcium and phosphate levels even while they remain Vitamin D deficient.


This important new review emphasises that in people who lack magnesium, supplementation with Vitamin D (and/or calcium) is likely to be ineffective, and may even be harmful - because adequate magnesium is essential for Vitamin D to work properly, and for normal calcium metabolism.

Nutrients work in synergy - and yet this fact is often ignored in clinical trials of supplementation, which test only the effects of single nutrients in isolation, as well as in clinical practice.

The authors also note that deficiencies of both Vitamin D and magnesium are widespread in populations consuming modern, western-type diets rich in ultra-processed foods.  (Sub-optimal intakes of magnesium are in fact now the norm, as are sub-optimal blood levels of Vitamin D). 

Both Vitamin D and magnesium are needed for the proper regulation of calcium - so adequate supplies of all three of these nutrients are needed to build and maintain strong bones and teeth, and prevent osteopororsis, for which Vitamin D is best known.

However, adequate supplies of both are also needed for innumerable other aspects of normal cell signalling, and therefore both brain and body health.

NB:  Although not covered in this review, Vitamin K2 is also essential for the proper regulation of calcium within the body - so adeaute supplies of this too are needed, alongside Vitamin D and magnesium. 

Unfortunately, however, the essentialty of Vitamin K2 (in addition to K1, which has long been recognised for its critical role in blood coagulation) has not yet been recognised in nutrition guidelines and recommendations.

See the underlying research here:

And for more information on the importance of Magnesium and Vitamin D fo brain as well as body health, see also the following lists of articles, which are regularly updated:

There is a caveat to the push for increased Vitamin D: Don't forget magnesium.

A review published in The Journal of the American Osteopathic Association found Vitamin D can't be metabolized without sufficient magnesium levels, meaning Vitamin D remains stored and inactive for as many as 50 percent of Americans.

"People are taking Vitamin D supplements but don't realize how it gets metabolized. Without magnesium, Vitamin D is not really useful or safe," says study co-author Mohammed S. Razzaque, MBBS, PhD, a professor of pathology at Lake Erie College of Osteopathic Medicine.

Razzaque explains that consumption of Vitamin D supplements can increase a person's calcium and phosphate levels even if they remain Vitamin D deficient. The problem is people may suffer from vascular calcification if their magnesium levels aren't high enough to prevent the complication.

Patients with optimum magnesium levels require less Vitamin D supplementation to achieve sufficient Vitamin D levels.

Magnesium also reduces osteoporosis, helping to mitigate the risk of bone fracture that can be attributed to low levels of Vitamin D, Razzaque noted.

Deficiency in either of these nutrients is reported to be associated with various disorders, including skeletal deformities, cardiovascular diseases, and metabolic syndrome.

While the recommended daily allowance for magnesium is 420 mg for males and 320 mg for females, the standard diet in the United States contains only about 50 percent of that amount. As much as half of the total population is estimated to be consuming a magnesium-deficient diet.

Researchers say the magnesium consumption from natural foods has decreased in the past few decades, owing to industrialized agriculture and changes in dietary habits. Magnesium status is low in populations who consume processed foods that are high in refined grains, fat, phosphate, and sugar.

"By consuming an optimal amount of magnesium, one may be able to lower the risks of Vitamin D deficiency, and reduce the dependency on Vitamin D supplements," says Razzaque.

Magnesium is the fourth most abundant mineral in the human body after calcium, potassium, and sodium.

Foods high in magnesium include almonds, bananas, beans, broccoli, brown rice, cashews, egg yolk, fish oil, flaxseed, green vegetables, milk, mushrooms, other nuts, oatmeal, pumpkin seeds, sesame seeds, soybeans, sunflower seeds, sweet corn, tofu, and whole grains.