The Study
Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial.
Think of this study like a science experiment where you give one group of people a special candy (magnesium) and another group a fake candy (placebo). You then measure a vitamin in their blood. Because the groups were chosen randomly, any difference in the vitamin levels must be because of the candy. So we can say the magnesium caused the changes in the vitamin levels. But we can only say that for the vitamin levels, not for whether they get sick or healthy.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study looked at whether taking a magnesium pill changes the amount of vitamin D in your blood. They found that it depends on how much vitamin D you already have. If your vitamin D is a bit low (around 30 ng/mL), magnesium can help raise it. If your vitamin D is already high (around 50 ng/mL), magnesium can help lower it, which might prevent too much vitamin D.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 584 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This means magnesium might help fine-tune your vitamin D levels so they stay in a healthy range, but the effect is moderate and depends on your starting point.
- 2If you already have healthy vitamin D levels, magnesium might not be necessary.
- 3At a starting vitamin D level of 30 ng/mL, magnesium raised it by about 2.8 units.
- 4At a starting level of 50 ng/mL, magnesium lowered it by about 6.9 units.
- 5Also, a breakdown product of vitamin D decreased when vitamin D was high, and a form of vitamin D called D2 increased even more as starting levels were higher.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The American journal of clinical nutrition
Year
2018
Authors
Q. Dai, Xiangzhu Zhu, J. Manson, Yiqing Song, Xingnan Li, A. Franke, R. Costello, A. Rosanoff, H. Nian, L. Fan, H. Murff, R. Ness, D. Seidner, Chang Yu, M. Shrubsole
Related Content
Claims (7)
In adults aged 40 to 85 whose diet has much more calcium than magnesium, taking magnesium pills for 12 weeks reduces a specific vitamin D byproduct in the blood, but only if their starting vitamin D level is at a certain value. This reduction does not happen when their vitamin D level is lower.
For people aged 40-85 who eat a lot of calcium compared to magnesium, taking magnesium for 12 weeks can raise a chemical form of vitamin D in the blood by a small amount—but only if they already have a certain level of vitamin D. This shows that magnesium helps the body make vitamin D when it's not too low.
Your body needs magnesium to make vitamin D work. Without it, the vitamin D you get from sunlight or food can't be turned into the active form that helps your body use calcium.
For older adults (40-85 years) who get a lot more calcium than magnesium from their food, taking a magnesium supplement for 12 weeks lowers the amount of vitamin D in the blood if that amount is already high (30-50 ng/mL). For example, if a person's vitamin D level is 50 ng/mL, it can drop by about 6.87 ng/mL. So magnesium helps the body keep vitamin D from getting too high.
For people aged 40 to 85 who eat a lot more calcium than magnesium, taking a magnesium pill for 12 weeks boosts their blood level of a specific form of vitamin D (vitamin D2). The boost is bigger when they already have more vitamin D at the start—up to 8 times higher compared to a sugar pill.
Taking magnesium can change how your body handles vitamin D, but the change depends on how much vitamin D you already have. Magnesium affects some forms of vitamin D in your blood but not the active form your body uses, so the effect of magnesium varies based on your starting vitamin D level.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.