We don’t usually think of nutritional supplements acting in concert, but that is due to a failure of imagination. Food hardly ever supplies a single nutrient. A reader recently alerted us to an interesting and intricate interaction between a mineral and a fat-soluble vitamin. She asked about taking magnesium to boost vitamin D.
Can You Take Magnesium to Boost Vitamin D Levels?
Q. Most of us do not get nearly enough vitamin D but taking a daily supplement of vitamin D3 may not be enough. I recently read that magnesium deficiency can prevent absorption of vitamin D supplements. Is this true?
A. Yes, it is, but the story is quite a bit more complicated. The enzymes that process vitamin D in our bodies require magnesium to function well.
How Scientists Studied Magnesium to Boost Vitamin D Levels:
A recently published study demonstrated that optimal magnesium status is important for improving circulating vitamin D (American Journal of Clinical Nutrition, Dec. 1, 2018). The scientists tested the effect of magnesium supplements on 25-hydroxyvitaminD3. They found that if a person’s initial vitamin D level was low (under 30 ng/ml), magnesium supplements helped raise it. On the other hand, if the initial vitamin D level was higher, between 30 and 50 ng/ml, magnesium supplements tended to reduce vitamin D levels. Here is what we wrote earlier about this study. Perhaps this complex relationship between magnesium and vitamin D status may help explain why people who get more magnesium are less prone to fractures.
Does Your Diet Have Enough Magnesium to Boost Vitamin D Levels?
Unfortunately, the majority of American adults don’t get adequate amounts of magnesium in their diets. First of all, pumpkin seeds (168 mg/ounce, shelled), almonds (80 mg/ounce) and cashews (74 mg/ounce) are great sources, but not part of everyone’s weekly fare. In addition, spinach (78 mg/half-cup cooked spinach), shredded wheat (61 mg/two-biscuit serving) and black beans (60 mg/half-cup serving) are also great sources. Are you eating them regularly? If not, you might want to consider a supplement.
Be careful, though: too much magnesium could lead to diarrhea. Moreover, no one with compromised kidney function should take magnesium supplements except under a doctor’s close supervision. That is because excess magnesium puts too much strain on poorly-functioning kidneys.
You can learn more about what vitamin D does and how you can get optimum levels in our Guide to Vitamin D Deficiency.