Calcium Plus Vitamin D supplies nutrients required for both the structural and nervous systems. Derived from bone meal and combined with other trace minerals needed by the body, this calcium more easily enters the body to help replenish bone tissue that is constantly being replaced. Calcium comprises half of all the minerals in the body, but this still only represents 2% of the body's entire weight. This formula also contains phosphorus, the second most abundant mineral n the body. It works with calcium, and both are commonly found in nature. This formulation provides calcium and phosphorus at a 2:1 ratio. Magnesium is also added in the same 2:1 ratio with calcium. Without these important ratios, the body begins to lose one or more minerals before they can be utilized.