Deficiency and insufficiency of vitamin D have both been well documented during the past decade. National survey data indicates that more than 40% of American adults are vitamin D deficient1,2 – defined as less than 20 ng/mL of serum 25(OH)D. On the bright side, data shows that 37% of U.S. adults report taking dietary supplements that contain vitamin D.1-3

A recent review published in The Journal of the American Osteopathic Association has determined that vitamin D is not metabolized efficiently without an adequate level of magnesium being present.4 But here’s the rub. According to World Health Organization statistics, as much as three-quarters of the U.S. adult population does not meet the U.S. Food and Drug Administration’s Recommended Daily Intake of magnesium – 420 mg per day.5

Considering the prevalence of the suboptimal intake of these two essential nutrients, it is eminently clear that individuals supplementing with vitamin D should also consider their magnesium status as well. Failure to maintain an adequate level of magnesium in the body could lead to inadequate vitamin D metabolism.* Furthermore, individuals with an adequate magnesium level were found to require less vitamin D supplementation to maintain a normal level of that vitamin.*4 Research has correlated diets higher in magnesium to lower incidences of vitamin D deficiency.*6 

Magnesium and vitamin D are vital bone nutrients, along with calcium and vitamin K.* An adequate magnesium level is required to activate vitamin D, which in turn regulates calcium and phosphorus metabolism to support bone health and maintenance.* 


  1. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010. 
  2. Forrest K, Stuhldreher W. Prevalence and correlates of vitamin D deficiency in US adults. Nutr Res 2011;31(1):48-54.
  3. Bailey R, Dodd K, Goldman J, et al. Estimation of total usual calcium and vitamin D intakes in the United States. J Nutr 2010;140:817-818.
  4. Uwitonze A, Razzaque M. Role of magnesium in vitamin D activation and function. J Am Osteopath Assoc 2018;118(3):181-189.
  5. [Accessed 4.2.18]
  6. Deng X, Song Y, Manson JE, et al. Magnesium, vitamin D status and mortality: results from U.S. National Health and Nutrition Examination Survey (NHANES) 2001 to 2006 and NHANES III. BMC Med 2013;11:187. doi:10.1186/1741-7015-11-187.