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You Might Not Be Getting All The Benefits Of Vitamin D If You're Low In Magnesium

Jessica Timmons
Author: Medical reviewer:
Updated on December 10, 2020
Jessica Timmons
By Jessica Timmons
mbg Contributor
Jessica Timmons is a freelance writer whose work has appeared in Healthline, Pregnancy & Newborn, Modern Parents Messy Kids, and more.
Marvin Singh, M.D.
Medical review by
Marvin Singh, M.D.
Integrative Gastroenterologist
Marvin Singh, M.D. is an integrative gastroenterologist in San Diego, California. He is trained and board certified in internal medicine and gastroenterology/hepatology.
Last updated on December 10, 2020

Vitamin D has been making headlines for its relationship to the pandemic, and a recent study found that in one cohort of patients hospitalized with COVID-19, 80% were deficient in the micronutrient.

While it's still too early to draw concrete conclusions, there is research that suggests vitamin D may indeed help prevent infection because of its ability to support lung health1 and boost immunity2.* COVID-19 aside, most of us understand it's important to get enough vitamin D. What isn't as well known is that it may actually be worth taking with a side of magnesium. Here's why.

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The relationship between magnesium and vitamin D.

The human body uses nutrients systematically, and proper absorption and metabolism of one nutrient often depend on the availability of another. Vitamin D and magnesium are a prime example. "The pathways in the body that result in activation of vitamin D involve a number of enzymes, and most or all of them require magnesium as a cofactor," explains double board-certified surgeon and author Kent Sasse, M.D. 

Magnesium actually plays a role in over 300 enzyme systems in the body, including the conversion of vitamin D into its active form. That form of vitamin D is needed in the bloodstream to absorb calcium. According to a study published in the Journal of the American Osteopathic Association, getting the recommended amount of magnesium is critical for obtaining the full benefits of vitamin D. 

That may pose a problem for some people: While magnesium is plentiful in foods like nuts and seeds, leafy greens, whole grains, and legumes, it's estimated that less than half of the U.S. population3 get the required daily amount.

Vitamin D deficiency is another issue affecting more than half the population. This deficiency boils down to a limited number of foods with naturally occurring vitamin D and minimal exposure to the sun. "There are very few foods that contain significant amounts of vitamin D," says Zara Patel, M.D., a researcher and associate professor at Stanford, "and much of what we produce in our bodies comes from sunlight and UV rays hitting our skin and producing the precursor molecules needed to make this vitamin." That means for those of us religiously using sunscreen and not eating stacks of fish—a great source of vitamin D!—we may need to supplement.

Getting enough of both nutrients is critical. Deficiencies in magnesium and vitamin D have been linked to a number of health conditions, including cardiovascular diseases4, metabolic issues5, and skeletal deformities6.

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Should you be taking them at the same time?

To correct vitamin D deficiency in adults, the U.S. Endocrine Society recommends 6,000 IU of vitamin D daily7 for 8 weeks (which would require a supplement), followed by a maintenance dose of at least 1,500 to 2,000 IU per day after that. Healthcare practitioners can test vitamin D status with a straightforward blood test.

And if you're routinely consuming refined grains in lieu of whole grains, you may be short on dietary magnesium, which ultimately affects your vitamin D levels. If you choose to supplement with magnesium, "taking less than 300 mg of magnesium for men and 270 mg for women is generally recommended," Sasse says.* "These are very safe vitamins and supplements, and they can be taken together."

The takeaway.

Ensuring that you're getting enough vitamin D to reap its many benefits is a great idea, and supplements make it easy. But magnesium plays an important role in converting that vitamin D into a usable form in the body. If you're worried that your diet doesn't include enough magnesium-rich foods, pairing your vitamin D with a magnesium supplement may be a savvy move.*

Jessica Timmons author page.
Jessica Timmons

Jessica Timmons has been working as a freelance writer since 2007 and has covered everything from parenting and pregnancy to residential and industrial real estate, cannabis, stand-up paddling, fitness, martial arts, landscaping, home decor, and more. Her work has appeared in Healthline, Pregnancy & Newborn, Modern Parents Messy Kids, and Coffee Crumbs. When she’s not stuck to her laptop, Jessica loves hanging out with her husband and four active kids, drinking really great lattes, and lifting weights. See what she’s up to at her website.