The active form of vitamin D (calcitriol) may slightly increase intestinal absorption of magnesium.
However, magnesium absorption does not seem to be calcitriol-dependent as is the absorption of calcium and phosphate.
High calcium intake has not been found to affect magnesium balance in most studies.
Inadequate blood magnesium levels are known to result in low blood calcium levels, resistance to parathyroid hormone (PTH) action, and resistance to some of the effects of vitamin D