The rate of calcium absorption seems to be directly proportional to the quantity of calcium binding proteins. Calcitriol’s primary regulatory role involves keeping blood calcium and phosphorus levels within a normal range. Calcitriol (1,25(OH)2D3) is the dihyroxylated form of vitamin D3.
Together, levels of these three harmonies continually rise and fall, adjusting blood calcium levels by changing urinary calcium excretion, intestinal calcium absorption and the flow of calcium in and out of bone.
Vitamin D and the absorption of calcium