Comment by amai

Coincidence? "Vitamin D is currently the only Essential Vitamin or Mineral which appears to have deficiency rates at a similar level to Magnesium"

https://examine.com/supplements/magnesium/research/#nutrient

Dai (2018): Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial https://pubmed.ncbi.nlm.nih.gov/30541089/ "Our findings suggest that optimal magnesium status may be important for optimizing 25(OH)D status. "

So it might well be that general deficiency in Vitamin D is caused by the deficiency in magnesium status. This would also be an explanation why we see Vitamin D deficiency in sunny Africa: https://theconversation.com/think-vitamin-d-deficiency-is-no...