Your Vitamin D Supplement Probably Isn’t Working. Here’s How to Change That


The benefits of vitamin D for general health and athletic performance have been well-documented.


Exogenous vitamin D supplementation is associated with increased upper- and lower-body strength, reduced injury risk, as well as improved sprint times and vertical jump height. Furthermore, having higher serum levels of vitamin D decreases your risk of many serious illnesses, ranging from depression to type 2 diabetes, cancer and even overall mortality.


That all sounds great on paper. But dietary sources of vitamin D are fairly scarce, limited largely to egg yolks, fatty fish and fortified products like cereals and milk. The easiest way to get vitamin D is from sunlight. Human skin creates significant amounts of vitamin D exposed to sunlight. However, getting enough sun exposure in cloudy, cold regions can be difficult. This is why vitamin D supplements have become hugely popular. Yet of the many people who pop vitamin D pills, surprisingly few people witness any of these perks.


How come?


According to a recent research review, it’s because they’re not eating enough magnesium. In fact, it is estimated that up to 75% of the total US population is consuming a magnesium-deficient diet.


Why is this important?


Because magnesium assists in the activation of vitamin D. Without sufficient magnesium levels, vitamin D can’t be metabolized. Simply put, if you’re deficient in magnesium, vitamin D remains stored and inactive in your body, and you won’t get its benefits.


How to Consume More Magnesium
Recommended daily allowance for magnesium ranges from 310 mg (females) to 420 mg (males). Magnesium can be found in many foods, including:


Nuts (Namely Cashews, Almonds, Brazil nuts)
Egg yolks
Green vegetables
Whole grains
Dark Chocolate


Although multiple food sources for magnesium exist, it is estimated that the standard US diet contains only about 50 percent of the recommended daily allowance. High levels of food processing and the increased consumption of fast food leaves many people lacking in magnesium.


The above sources are relatively high in magnesium, but it can still be quite difficult to get adequate amounts purely through diet. For example, one medium avocado, half a fillet of salmon, a serving of cashews and one banana still only add up to 57 percent of the recommended daily intake.


Unless you’re willing to eat a boatload of bananas or endure bodily gas bombs after consuming a few cans of beans every day, your best course of action to ensure recommended magnesium intake is through daily supplementation. That way, you’ll also obtain the optimal health and performance benefits of vitamin D.



Abrams, GD et al. “Effects of Vitamin D on Skeletal Muscle and Athletic Performance.” Journal of the American Academy of Orthopaedic Surgeons. 2018 Apr; 26(8):278-285.

Chiang, CM et al. “Effects of Vitamin D Supplementation on Muscle Strength in Athletes: A Systematic Review.” Journal of Strength and Conditioning Research. 2017 Feb; 31(2):566-574.

Close, G et al. “Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: Implications for skeletal muscle function.” Journal of Sports Sciences. 2013; 31(4):344–353.

Galesanu, C & Mocanu, V. “Vitamin D Deficiency and the Clinical Consequences.” Revista medico-chirurgicala a Societatii de Medici si Naturalisti din Iasi. 2015 Apr-Jun; 119(2):310-318.

Uwitonze, AM. “Role of Magnesium in Vitamin D Activation and Function.” Journal of the American Osteopathic Association. 2018 Mar; 118(1):181-189.



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