TR Klompmaker proposed that adequate calcium intake should be determined on the basis of the function of osteoblast. Excess calcium intake may accelerate the osteoblastic function by promoting replication of osteoblast, resulting in increase of the rate of apoptosis of osteoblast and in the increased rate of fracture. Another point is that the higher calcium intake does not necessarily result in the decreased incidence of fracture from the comparison of incidence of fracture and calcium intake among various countries. We have not yet had enough data to support the adequate calcium intake and thus need to have definite criteria to evaluate the adequate intake of calcium.