Magnesium is a trace mineral and micronutrient used by every organ system in your body. It is vital to cardiovascular function, large muscle control, and the adrenal system. Magnesium is responsible for more than 300 biochemical reactions in the body and has an impact on immune function, metabolism, and bone health; the bones store about 60 percent of all magnesium reserves.  Dr. Amy explains how up to 50% of people do not get enough magnesium in their diet. A lack of this vital mineral causes a range of symptoms.