Magnesium is the most important of these co-factors and is the key factor in converting vitamin D3 into 1,25 dihydroxyvitamin D, the only form of vitamin D the body can use.
However, it is estimated that 70% of the population are magnesium deficient and it is common for rising Vitamin D levels to exacerbate an underlying magnesium deficiency. If you have even a MILD unrecognized magnesium deficiency, your signs of magnesium deficiency are going to be amplified greatly when Vitamin D is taken - particularly in the large doses commonly required in order to attain recommended optimum serum levels of Vitamin D. If one is having problems supplementing with Vitamin D, a magnesium deficiency could be the reason why.
As well as being a cofactor for Vitamin D, Magnesium is a cofactor in more than 300 enzymatic reactions in the body. It is necessary for the transmission of nerve impulses, muscular activity, temperature regulation, detoxification reactions, and for the formation of healthy bones and teeth. It is involved in energy production and the synthesis of DNA and RNA.
Adequate magnesium intake and reserve is required for the synthesis of calcitriol, the active dihydroxy metabolite of vitamin D. Magnesium deficiency causes abnormal calcium utilisation, extending to hypocalcemia, by impairing parathyroid hormone (PTH) secretion, release and interfering with end-organ response to PTH.
For further information on Magnesium please visit the Magnesium Online Library
40fYME® International D3 with Cofactors (5000iu) contains 100mg of Magnesium.