Vitamin D and Magnesium - The Missing Link
Vitamin D and Magnesium: A Missing Link
Vitamin D Deficiency:
During the darkness of winter, Vitamin D becomes a nutrient that people are often concerned about getting enough of, and for good reason. Vitamin D deficiency has been linked to an array of diseases such as rickets, diabetes, cardiovascular disease, osteoporosis, autoimmune diseases and cancer. It is also an essential nutrient for muscular function and immunity. Despite the known importance of this nutrient, the prevalence of vitamin D deficiency is growing with an estimated 40% of the population being deficient.  (See Table 1 for DRIs/Vitamin D)
Preventing vitamin D deficiency usually requires supplementation as most people do not consume adequate amounts of vitamin D from food or spend enough time in sunlight for their bodies to synthesize sufficient amounts through their skin. (See Table 2 for Vitamin D Food Sources) For optimal absorption of vitamin D to occur, several nutrients have to act in tandem. One such important nutrient that is quickly coming to awareness in recent research is magnesium.
The Vitamin D and Magnesium Connection:
A recent study published in the American Journal of Clinical Nutrition revealed that optimal magnesium intake promotes desirable vitamin D levels by increasing levels of vitamin D in the blood. 
Magnesium plays this critical role in the body’s ability to metabolize vitamin D in the following ways:
· Activation of vitamin D – helps regular calcium and phosphate homeostasis which determines how bones grow and develop.
· Serves as a cofactor for all the enzymes that metabolize vitamin D.
Unfortunately, the relationship between magnesium and vitamin D is often overlooked and not discussed in most healthcare settings or in the education of the public. Using laboratory data to determine vitamin D status has become common practice, but rarely is magnesium considered. Because of this, supplementation with vitamin D has become common practice but can further exacerbate magnesium deficiency. 
In addition to optimizing vitamin D status, magnesium hosts an array of other important functions. The National Institutes of Health websites outlines that functions of magnesium as follows:
· a cofactor in more than 300 enzyme systems that regular diverse biochemical reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control and blood pressure regulation.
· required for energy production, oxidation phosphorylation, and glycolysis.
· contributes to the structural development of bone and is required for the synthesis of DNA, RNA and the antioxidant glutathione.
· plays a role in the active transport of calcium and potassium ions across cell membranes, a process that is important to nerve impulse conduction, muscle contraction, and normal heart rhythm.”
Research indicates that the majority of adults are deficient in both vitamin D and magnesium, which continues to go unrecognized and unaddressed by many health professionals. Screening for magnesium deficiency can be difficult because normal lab levels may still be associated with moderate to severe deficiency.  Signs of magnesium deficiency can include loss of appetite, nausea, vomiting, fatigue and weakness. Symptoms can progress as deficiency increases. For some, signs of magnesium deficiency can be nonexistent, resulting in the deficiency not being addressed.
Magnesium deficiency can be caused by a variety of factors such as consuming too much alcohol, inadequate absorption due to GI-related issues, stress, etc. Another factor that promotes deficiency is that most individuals do not consume adequate amounts of magnesium in their diets. According to NHANES, 79% of US adults do not consume the the recommended amount of magnesium. 
Sources of Magnesium:
In order to consume enough magnesium, first consider including magnesium-rich food sources such as green leafy vegetables, legumes, nuts, seeds and whole grains. Other foods such as salmon, halibut and dark chocolate are also excellent sources. In addition to magnesium, these foods are nutrient-dense sources of fiber as well as other important nutrients. For more information, on food sources of magnesium, check out this link.
If you are unable to meet the RDA for magnesium, then supplementation may need to be considered. Magnesium supplements are available in different forms:
· Magnesium glycinate - the most absorbable form; supports muscle relaxation and stress relief
· Magnesium sulfate - found in Epsom salt and can be absorbed in the body during baths. This can be beneficial for muscles and has a mild laxative effect.
· Magnesium citrate – highly absorbable; supports GI function and can be beneficial for constipation.
· Magnesium oxide – lowers level of absorption; found in Milk of Magnesia
· Magnesium theonate – supports cognitive function
Too much magnesium from supplements or medication can result in diarrhea and be accompanied by nausea or abdominal cramping so consult with your doctor or registered dietitian nutritionist prior to taking any new supplement.
1. Reddy P., Edward L.R. Am J Ther 2019 Jan/Feb; 26(1): e124-3132
2. Parva N. et al. Cureus 2018 Jun; 10(6): e2741
3. Dai Q. et al. The American Journal of Clinical Nutrition Dec 2018; 108(6): 1249-1258